Unit 5: Cardiovascular and Lymphatic System

Orthostatic hypotension p. 1140

(Postural) hypotension: -Lack of normal blood pressure compensation in response to gravitational changes on the circulation, leading to pooling and vasodilation -Acute versus chronic orthostatic hypotension -orthostatic (postural) hypotension means a decrease in systolic and diastolic arterial BP on standing -systolic BP decrease of at least 20 mmHg or a diastolic BP decrease of at least 10mmHg within 3 minutes of standing up -categorized as arteriolar, venular, or mixed -compensatory changes during standing normally increase sympathetic activity mediated through stretch receptors (baroreceptors) in the carotid sinus and the aortic arch -this reflex response to shifts in volume caused by postural changes leads to a prompt increase in heart rate and construction of the systemic arterioles, which maintains a stable BP -these compensatory mechanisms are not effective in maintaining a stable blood pressure in peeps with this. -may be acute or chronic -idiopathic, primary is the term for htn in which there is no known initial cause -ages 40-70yrs -affects men more than omen -older adults may be more affected by chronic orthostatic hypotension -significant risk factor for falls and associated injuries and has been associated with an increased risk for cv events -in addition to cv symptoms impotence and bowl and bladder dysfunction often are found in this type. *clinical manifestations: -is accompanies by dizziness blurring, or loss of vision and syncope or fainting -24 hour BP monitoring is recommended to dx

cardiomyopathy path effects Table 32-8 p.1166

*dilated cardiomyopathy: major sx- fatigue, weakness, palpitations. moderate/marked cardiomegaly. hypertrophy left ventricular myocardium. chamber volume increased. chamber compliance increased. systolic function- contractility decreased in left ventricle. conduction defects are intraventricular. dysrhythmias- sinoartial tachycardia, atrial and ventricular dysrhythmias. thromboembolism is systemic/pulmonary. associated conditions- alcoholism, pregnancy, infection, nutritional deficiency, exposure to toxins. eventually results in left heart failure. *hypertrophic cardiomyopathy: major sx- dyspnea, angina pectoris, fatigue, dizziness (syncope), palpitations. mild/moderate cardiomegaly. hypertrophy- left ventricular myocardium and interventricular septum. chamber volume decreased particularly in left ventricle. chamber compliance decreased particularly in left ventricle. normal myocardial contractility (systolic function). nonspecific conduction defects. atrial and ventricular dysrhythmias. thromboembolism- systemic/pulmonary. associated conditions- inherited defect of muscle growth and development or HTN. eventually results in left heart failure. *restrictive cardiomyopathy: major sx- dyspnea, fatigue. mild cardiomegaly. hypertrophy- left ventricular myocardium. chamber volume- normal/decrease. decreased chamber volume particularly in left ventricle. no altered systolic function. atrioventricular conduction defects. tachydysrhythmias. thromboembolism- systemic/pulmonary. associated conditions- infiltrative disease. eventually results in right heart failure.

Structural and functional changes in MI p.1159/1160

*tissue changes after MI p.1159 Table 32-7 -6-12 hours - no gross changes; sub cellular cyanosis with decreased temp, healing hasn't begun 18-24 hours - pale to gray-brown, slight pallor, inflammatory response, intercellular enzyme release 2-4 days : visible necrosis, yellow-brown in center and hyperemic around edges, proteolytic enzymes remove debris; catecholamines; lipolysis; and glycogenolysis elevate plasma glucose and increase free fatty acids to assist depleted myocardium recovery from anaerobic state 4-10 days : area soft, with fatty changes in center, regions of hemorrhage in infarcts area, debris cleared, collagen matrix laid down 10-14 days: weak, fibrotic scar tissue with beginning revascularization, healing continues but area very mushy, vulnerable to stress 6 weeks - scarring usually complete, tough I elastic scar replaces necrotic myocardium. -gross tissue changes in the area of infarction may not become apparent for several hours, despite almost immediate onset (within 30-60 seconds) of ECG changes -the infarcted myocardium is surrounded by a zone of hypoxia injury which may progress to necrosis, undergo remodeling or return to normal. -cardiac tissue surrounding the area of infarction also undergoes pathophysiologic changes -myocardial stunning is a temporary loss of contractile function that persists for hours to days after perfusion, has been restored. -this pathophisiologic state can occur both with MI and in peep who suffer ischemia during CV procedures such as surgery -stunning is caused by the alterations in electrolyte pumps, calcium homeostasis and the release of toxic oxygen radicals -it is characterized by decreased contraction and condition and can contribute to heart failure, shock, and dysrhythmias -stunning is less severe in individuals who have experienced ischemic preconditioning.

Truncus Arteriosus p.1217

--Mixed defect -Failure of the large embryonic artery to divided into the PA and aorta -results in a single vessel arising from both ventricles providing blood flow to the pulmonary and systemic circulations -common trunk saddles the VSD (always present) and has a single valve with three or four leaflets, which may result in stenosis, regurgitation or both -a right aortic arch is present 50% of the time -four types -Type 1 is the most common and involves the main PA arising from the truncus and then dividing into right and left Pas Most common (60%); the main pulmonary artery arises from the truncus. -type II is less common and involves the PAs arising from the posterior aspect of the truncus, 20%. -Type 3 is the least common and involves the PAs arising from the lateral aspect of the truncus, 10%; -Type 4, pseudotruncus, is now considered a severe form of TOF with the bronchial arteries arising from the descending aorta to supply the lungs. *patho: -blood flow from the RV and LV is pumped into the main truncus, resulting in mixing of the pulmonary and systemic circulations -differential flow out to either the pulmonary bed or the systemic circulation depends on the pulmonary and systemic vascular resistance -generally the pulmonary vascular resistance is less than the systemic vascular resistance, resulting in the majority of blood flow traveling to the lungs -this may be altered, because of PS, small purlmonary arteries or increased pulmonary vascular resistance -pulmonary vascular disease develops early with this defect because of increased pulmonary blood flow. *clinical manifestations: Physical findings depend on amount of pulmonary blood flow and presence of other cardiac anomalies. if PS is present a newborn will present with cyanosis caused by already elevated pulmonary vascular resistance but no heart failure. Conversely if PS is not present- the newborn initially will have mild to moderate cyanosis that worsens with activity. Once pulmonary vascular resistance drops, the pulmonary bed will receive preferential flow and the infant will have signs of heart failure. A harsh systolic regurgitant murmur is usually present along the left sternal border as a result of VSD and a systolic click at the apex and left upper sternal border may be present reflecting opening of the truncle valve. An apical rumble with or without a gallop rhythm also may be present because of increased pulmonary blood flow. if truncal valve insufficiency exists- an early diastolic high-pitched decrescendo murmur may be present.

Total anomalous pulmonary venous connection (TAPVC) p.1216

--Mixed defect -Nonobstructive versus obstructive -Return, occurs when the pulmonary veins abnormally connect to the R side of the heart either directly or through one or more systemic veins that drain into the RA -an ASD generally is present also -extremely rare -four types are based on the site of the drainage -supra cardiac are the most common form and drain to the superior vena cava through the vertical or innominate vein -Cardiac drain directly into the RA or through the coronary sinus -Infracardiac traverse the diaphragm and drain into the portal or hepatic vein or the inferior vena cava -mixed are a combo of the various types -partial is a condition in which only one or two of the pulmonary veins, usually the right-sided veins, drains into the RA or one of its tributaries. *patho: -differentiated into two groups: no obstruction and obstructive to pulmonary venous drainage -hemodynamics of the no obstructive group involve the RA receiving the oxygenated blood that would normally flow into the LA -amount of blood shunted unto the LA vs the column entering the RV depends on the size of the ASD and compliance of the RV -if the ASD is restrictive and RV compliance approaches normal, more blood will enter the RV than the LA, resulting in RA and RV enlargement as well as increased pulmonary blood flow -increased pulmonary venous blood return and larger amounts of saturation blood -if the ASD is unrestrictive and the RV doesn't become thinner to increase compliance, the majority of the mixed saturated blood is shunted from the higher pressure RA to the LA -the hemodynamics of obstructed cause pulmonary venous hypertension because of resistance caused by the obstruction resulting in an elevation in pulmonary vascular and RV pressures -pulmonary edema occurs from the hydrostatic capillary pressure exceeding the osmotic pressure of the blood and eventually contributing to the development of HF -this group has a strong association with the Infracardiac type of this and is a surgical emergency. *clinical manifestations: The predominant clinical manifestation is cyanosis caused by mixing of oxygenated and deoxygenated blood entering the systemic circulation. the degree of cyanosis is inversely related to the amount of pulmonary blood flow. children with unobstructed TAPVC may be asymptomatic until pulmonary vascular resistance drops at which time pulmonary blood flow will increase resulting in signs of pulmonary over circulation, particularly growth retardation and frequent pulmonary infections, in addition to mild cyanosis. Obstructed TAPVC results in cyanosis and rapid deterioration necessitating immediate surgical correction or death will occur. PE- Systolic murmur at the left upper sternal border and a mid diastolic murmur at the left lower sternal border. a murmur may be absent in the obstructed TAPVC. A characteristic quadruple rhythm consisting of S1, widely split S2, and S3 or S4, or a gallop rhythm also is present.

Atherosclerosis p. 1145/1146

-A form of arteriosclerosis in which thickening and hardening of the vessel are caused by the accumulation of lipid-laden macrophages within the arterial wall, which leads to the formation of a lesion called a plaque -this isn't a single dz but rather a pathologic process that can affect vascular systems throughout the body, resulting in ischemic syndromes that can very widely in their severity and clinical manifestations -it is the leading cause of coronary artery and cerebrovascular dz. *patho: -Progression: Endothelium injury-> Inflammation of endothelium -> Cytokines released -> Cellular proliferation -> Macrophage migration -> Low-density lipoproteins (LDL) oxidation (foam cell formation) with oxidative stress -> Fatty streak -> Fibrous plaque -> Complicated plaque -inflammatory dz that develops and proceeds in the presence of elevated plasma cholesterol levels -innate and adaptive immunity play a role in the dev and progression of the lesions -the lesions progress from endothelial injury and dysfunction to a fatty streak to fibrotic plaque to complicated lesion -begins with injury to the endothelial cells that line artery walls -possible causes of endothelial injury include the common risk factors for this, such as smoking, hypertension, diabetes, increased LDL, decreased HDL, and autoimmunity -other causes of endothelial injury include inflammatory factors that are being explored as non traditional cv risk factors, such as elevated CRP, increased serum fibrinogen, infection, and periodontal dz -those with a defect in the production of precursor endothelial cells in the bone marrow are at a greater risk for this bc the precursor cells aren't available to repaired injured endothelium -once injury has occurred, endothelial dysfunction and inflammation lead to: 1) injured endothelial cells become inflamed and can't make normal amounts of anti thrombotic and vasodilator cytokines 2)numerous inflammatory cytokines are released, including TNF-a, interferon-gamma, interleukin 1, toxic oxygen radicals, CRP and heat shock protein 3) macrophages adhere to injured endothelium by way of adhesion molecules such as vascular cell adhesion molecule-1 4) these macrophages then release enzymes and toxic oxygen radicals that created oxidative stress, oxidize LDL, and further injure the vessel wall 5) growth factors also are released, including angiotensin II, fibroblast growth factor, TGF-B, and platelet-deprived growth factor, which stimulated smooth muscle cell proliferation in the affected vessel -LDL penetrated into the subintima of arterial walls, where it is trapped by proteoglycans -inflammation, oxidative stress, and activation of macrophages caused the aggregated LDL to become oxidized -DM, smoking and HTN (esp with increased levels of angiotensin II) contribute to increased LDL oxidation -oxidized LDL is toxic to endothelial cells and causes smooth muscle proliferation -oxidized LDL also increases endothelial adhesion molecule expression, which recruits more monocytes/macrophages that penetrate the vessel wall. -several types of receptors on these macrophages enable detection and engulfment of the LDL, which contributes to activation of additional innate and adaptive immune responses -macrophages filled with oxidative LDL are called foam cells -once these lipid-laden foam cells accumulate in significant amounts, they form a lesion called a fatty streak -these lesions can be found in the walls of arteries of most people, even young children -once formed, fatty streaks produce more toxic oxygen radicals and cause immunologic and inflammatory changes, resulting in progressive damage to the vessel wall -smooth muscle cels proliferate, produce collagen, and migrate over the fatty streak forming a fibrous plaque -this process is mediated by many inflammatory cytokines, including growth factors -the fibrous plaque may calcify, protrude into the vessel lumen and obstruct blood flow to distal tissues, esp during exercise which may cause symptoms (angina, intermittent claudication). -many plaques are unstable meaning they are prone to rupture even before the affect blood flow and are clinically silent until they rupture -plaque rupture occurs because of the inflammatory activation of proteinase a (matrix metalloproteinases and Cathepsins) , apoptosis of cells within the plaque and bleeding within the lesion (plaque hemorrhage) -plaques that have ruptured are called complicated plaques -once rupture occurs, exposure of underlying tissue results in platelet adhesion, initiation of the clotting cascade, and rapid thrombus formation that may suddenly occlude the affected vessel, resulting in ischemia and infarction -aspirin or other anti thrombotic agents are used to prevent this complication. *clinical manifestations: signs and signs are a result from inadequate tissue perfusion because of obstruction of the vessel that supply them. partial vessel instruction may lead to transient ischemic events often associated with exercise or stress. Once the lesion becomes complicated, increasing obstruction with superimposed thrombosis may result in tissue infarction. CAD caused by artherosclerosis is the major cause of myocardial ischemia and is one of the most important health issues in the US. obstruction of the vessels supplying the brain is the major cause of stroke. Similarly any part of the body may become ischemic- Often more than one vessel is involved in the disease, consequently the individual may present with symptoms from several ischemic tissues at the same time. thus- disease in one area may indicate risks for other ischemic complications elsewhere. ??-An embolus is a bolus of matter that is circulating in the blood, occlusion in a blood vessel caused by a bolus of circulating matter in the bloodstream. A thrombus is a blood clot that remains attached to the vessel wall.

Coronary Artery Disease p.1148

-Any vascular disorder that narrows or occludes the coronary arteries -Results in an imbalance between coronary supply of blood and myocardial demand for oxygen and nutrients -Reversible myocardial ischemia or irreversible infarction may result. -Most common cause: Atherosclerosis -Nonmodifiable risk factors: Advanced age; family history Male gender or women after menopause -Modifiable risk factors: Dyslipidemia, Hypertension Endothelial injury, increase in myocardial demand Cigarette smoking, Vasoconstriction and increase in LDL, decrease in high-density lipoproteins (HDL), Diabetes mellitus and insulin resistance, Endothelial damage, thickening of the vessel wall, Obesity and/or sedentary lifestyle, Obesity, dyslipidemia, and hypertension: Metabolic syndrome, Atherogenic diet -Nontraditional risk factors: Markers of inflammation and thrombosis, C-reactive protein, Troponin I, Hyperhomocysteinemia, Adipokines, Adiponectin and leptin, Infection, Microorganisms and periodontal disease Air pollution , Coronary artery calcification, carotid wall thickness

Tricuspid atresia (TA) p.1209

-Defects Decreasing Pulmonary Blood Flow -Consists of an imperforate tricuspid valve, resulting in no communication between the RA and RV -3rd most common cyanotic heart defect -combo of defects, including the imperforate tricuspid valve as well as a septal defect, hypoplastic or absent RV, enlarged mitral valve and LV and varying degrees of pulmonary stenosis -also may be associated with transposition of the great vessels -most common type involves a hypo plastic RA with decreased pulmonary blood flow, ASD, VSD and normally related great vessels. *patho: -systemic blood returns through the superior and inferior venae Cavae to the RA -venous return flows through the ASD into the LA, mixing with blood returning from the pulmonary circulation -the blood then enters the LV -most of this blood passes into the systemic circulation through the aorta, but varying amounts flow through the VSD into the hypo plastic RV and to the lungs -pulmonary circulation depends on the presence of a VSD and the presence of a functioning RV of reasonable capacity -if the RV is absent, the pulmonary valve is usually imperforate as well -a PDA is necessary to ensure that some blood flows into the pulmonary circulation -pulmonary circulation also depends on the relationship between pulmonary and systemic vascular resistance -as long as pulmonary resistance is low than systemic resistance, blood flows through the VSD from L to R, feeding the pulmonary circulation -if pulmonary resistance rises above systemic resistance, pulmonary blood flow will be significantly diminished. *clinical manifestations: some degree of central cyanosis is common in tricuspid atresia depending on the amount of pulmonary blood flow. growth failure is uncommon in children- experience exertional dyspnea, tachypnea, and hypoxemia. long-term effects of hypoxia are polycythemia and clubbing. children also display hypercyanotic spells. hepatomegaly may be present if the ASD is restrictive or CHF occurs as a result of increased pulmonary blood flow. The VSD causes systolic or regurgitant murmur- the murmur is likely to be softer and shorter as the VSD enlarges. a narrowly split-second heart sound caused by decreased pulmonary blood flow may be present or the second heart sound maybe single if there's pulmonary atresia.

Tetralogy of Fallot (TOF) p.1207, 1208, 1209

-Defects Decreasing Pulmonary Blood Flow -Consists of four defects: a large VSD that is high in the septum, an overriding aorta that straddles the VSD, pulmonary stenosis, and RV hypertrophy -most common cyanotic congenital heart defect and accounts for 10% of all defects *patho: -develops during 2 phases of embryologic growth: 1) during the division of the truncus arteriousus by the spiral septum in the 3rd or 4th week of gestation and 2) during the division of the ventricles between the 4th and 8th week of gestation -normally as these events progress, the truncated septum fuses with the bulbar ridges and in turn with the endocardial cushions -the membranous portion of the interventricular septum grows upward to meet the endocardial cushions and ultimately all of these tissues untie to complete the interventricular septum. -the embryologic error that cases this is not definitively known, but two theories have been proposed -1) truncus arteriousus divides unevenly, resulting in great vessels of unequal size -2) infundibulum overgrowth in the RV is the major developmental anomaly -defects in ventricular septation also occur, producing the large VSD which allows the aorta to override the VSD. -the pathophysiology associated with this varies widely depending primarily on the degree of pulmonary stenosis, the size of the VSD, and the pulmonary and systemic resistance to the flow -bc the VSD is usually large, pressures are equal in the RV and LV -the major determinant of shunt direction through the VSD is the difference between pulmonary and systemic vascular resistance -infants who have little or no right-to-left shunting are acyanotic and are known as "pink tets" -they may have a net left-to-right shunt similar to a large VSD -if pulmonary vascular resistance is higher than systemic resistance, the shunt is from right to left -because many factors can alter the balance between pulmonary and systemic resistance, shunt direction is not necessarily constant. -pulmonary stenosis decreases blood flow to the lungs and the amount of oxygenated blood that returns to the left heart -if blood also shunts from right to left through the VSD, deoxygenated blood mixes with the oxygenated blood returning from the lungs -result is low oxygen saturation (hypoxemia) in the systemic circulation -the body attempts to compensate for chronic hypoxemia by producing more red blood cells (thereby causing polycythemia) and by increasing blood flow to the lungs through collaterals bronchial vessels in long-standing cases. *clinical manifestations: as long as the ductus arteriosus remains open- the newborns pulmonary blood flow may be adequate. as the ductus closes, cyanosis becomes apparent. chronic hypoxemia causes clubbing of the fingers and toes. rare manifestation- sudden onset of dyspnea, cyanosis, restlessness (hypercyanotic spell/tet spell) generally occurs with crying and exertion. cause of episode is unknown (RV possibly goes into spasm or systemic resistance drops suddenly. relative or actual increase in pulmonary vascular resistance increases the right to left shunt and the cyanosis. hypercyanotic spells are often the event that initiates surgical intervention. if spells or frequent or do not terminate- medical emergency. infants may have difficulty feeding b/c exertion required increases hypoxia, they experience slow growth and FTT. most infants with this grow normally. squatting is a spontaneous compensatory mechanism used by older children with unrepaired TOF to alleviate hypoxic spells. squatting increases systemic resistance while decreasing venous return to the heart from the inferior vena cava. decrease of systemic return makes relatively more oxygenated blood available to the body. the increase of systemic resistance reverses the shunt through the VSD to a left to right shunt, has the effect of increased pulmonary blood flow. through these mechanisms, squatting temporarily decreases the degree of hypoxemia. uncommon to witness this because most cases are surgically corrected in early infancy. typical heart murmur- pulmonary systolic ejection murmur caused by the obstruction in the outflow tract which creates turbulence during systole. more obstruction to flow (smaller orifice) produces louder murmur- why murmur often disappears during hypoxic spell, when obstruction decrease and pulmonary blood flow decreases to a minimal amount. the second hart sound seems to single but in fact it is not. the pulmonary component is very soft and delayed, usually not heard although present. enlarged RV may cause the left side of the chest to be more prominent and a "heave" also may be palpated.

Atrial septal defect (ASD) p.1204/1205

-Defects Increasing Pulmonary Blood Flow -Abnormal communication between the atria -Allows blood to be shunted from left to right -although it's an isolated lesion, is the 4th most common congenital heart defect, 5-10% of all congenital cardiac defects Three major types of defect: Ostium primum, Ostium secundum, Sinus venosus 3 major types are: 1) an ostium primum defect, an opening found low in the septum that may be associated with AV valve abnormalities, esp mitral insufficiency 2) an ostium secundum defect, an opening in the center of the septum (most common type of atrial defect) 3) a sinus venosus defect, an opening that occurs high up in the atrial septum near the superior vena cava and RA junction. -often associated with partial anomalous pulmonary venous connection. *patho: -although the pressure difference between the two atria is minimal, this allows blood to be shunted from left to right because of the slightly higher pressure of the left atrial chamber and low pulmonary vascular resistance as compared with systemic vascular resistance -right atrial and ventricular enlargement develops as a result of left-to right shunting -children are generally asymptomatic and rarely display signs of pulmonary over circulation -moderate to large these allows an increase in pulmonary blood flow and over time, pulmonary vascular changes can occurs that may, result in pulmonary hypertension -crescendo-decrescendo systolic ejection murmur. *clinical manifestations: most are asymptomatic- dx made during routine PE- auscultation of crescendo-decrescendo systolic ejection murmur, reflects increased blood flow through the pulmonary valve. location is btw 2nd and 3rd ICS along left sternal border. wide fixed slitting of 2nd heart sound also characteristic of ASD (reflects volume overload to the RV, causing prolonged ejection time and delay of pulmonic valve closure.

Ventricular Septal defect (VSD) p.1205

-Defects Increasing Pulmonary Blood Flow -Abnormal communication between ventricles -Shunting from the high-pressure left side to the low-pressure right side -Pulmonary overcirculation accounts for symptoms associated with a large VSD Types of VSDs: Perimembranous, Muscular, Supracristal, AV canal or inlet -most common type of congenital heart lesion and account for 25% to 33% of all congenital heart defects -4 types of VSDs are based on location in the septum -peri membranous type which occurs in the outflow tract of the LV immediately below the aortic valve, is the most common type, accounting for up to 80% of all these that require tx -muscular these, which occur low or anterior in the ventricular septum between the trabeculae are most likely tot close spontaneously and are difficult to close surgically bc of their location low in the ventricular apex -most muscular these are hemodynamically insignificant and require no medical or surgical tx -supercristal these also called outlet these occur in the right ventricular outflow tract or infundibulum below the pulmonary valve -AV canals or inlet these occur posterior and inferior to the membranous system, beneath the septal cusp o ft he tricuspid valve and interior to the papillary muscles of the conus. *patho: -the direction of shunting in a child with this is from the high-pressure left side to the low pressure right side -the amount of shunting depends on the size of the defect and the degree of pulmonary vascular resistance -small these present increased resistance to shunting and limit blood flow through the defect; the the degree of pulmonary vascular congestion and ventricular chamber enlargement is minimal -after 1-2 weeks of life, when pulmonary vascular resistance has decreased, moderate-sized to large VSDs allow a large amount of shunting from left to right -the shunted blood flows directly out the RV outflow tract and into the PA rather than remain in the RV cavity -the main PA, LA and LV all enlarge, -LV hypertrophy occurs to effectively pump the additional volume -pulmonary overciulation accounts for the sx association end with a large this in most cases -over time the pulmonary bed also undergoes changes because of increased pulmonary blood flow caused by the left-to-right shunting -the smooth muscle layer in the arteriolar walls thickens and proliferation of the intimate layer occurs -the effect of these changes is a decrease in the diameter of the pulmonary vessels, which increases the resistance to blood flow -if the pulmonary vascular resistance is severely increased these changes eventually become irreversible, and pulmonary vascular resistance causing the shunt through this to reverse direction -deoxygenated blood now flows into the systemic circulation and cyanosis occurs, a phenomenon known Eisenmenger syndrome. *clinical manifestations: manifestations depend on the age of the child, size of the defect, and levels of pulmonary vascular resistance. newborns with small VSDs are relatively asymptomatic. initially no murmur is present b/c newborns high pulmonary vascular resistance causes equalization of the pressures btw both ventricles. once pulmonary vascular resistance drops, left to right shunting occurs, creating murmur. large VSDs- symptoms of HF and poor weight gain. adults who develop pulmonary vascular obstructive disease as a result of unrepaired VSD will be cyanotic and have clubbing. PE- loud, harsh, holosystolic murmur and systolic thrill can be detected at the left lower sternal border. intensity of the murmur reflects the pressure gradient across the VSD. an apical diastolic rumble may be present with a moderate to large defect, reflecting increased flow across the mitral valve.

Atrioventricular canal defect (AVC) p.1206

-Defects Increasing Pulmonary Blood Flow -Abnormalities demonstrated in the atrial and ventricular septa and AV valves -Complete, partial, and transitional AVC defects -Results from nonfunction of the endocardial cushions during fetal life, yielding abnormalities in both the atrial and ventricular septa and the AV valves -this defect accounts for as many as 5% of all congenital heart defects, and approx 30% of these occur in chidlren with Down syndrome -three types of these are based on the cardiac componenents involved -Complete defects consists of an inlet VSD, a primum type of ASD, and defects in both the mitral and tricuspid valves -Partial defects consist of a primum type of ASD and a cleft in the septal or anterior leaflet of the mitral valve -transitional defects involve partial fusion of the endocardial cushions, resulting in variable AV valve abnormalities. *patho: -hemodynamics abnormalities seen in this depend on the componenents of the lesion and the level of pulmonary vascular resistance -shunting is minimal during the neonatal period when pulmonary vascular resistance is high -once pulmonary vascular resistance drops, left-to-right shunting occurs through the septal defects; resulting in increased pulmonary blood flow and HF -partial defects mimic the hemodynamics of secundum ASD in which the left-to-right shunting through the primum ASD causes RA and RV dilation and increased pulmonary blood flow -the mitral regurgitation that occurs, caused by the cleft mitral valve is usually hemodynamically insignificant -complete defects reflect the hemodynamics so far an ASD and a VSD, resulting in biatrial and biventricular enlargement RA and RV volume overload occurs bc of shunting though the primum ASD and tricuspid regurgitation -LA and LV volume overload occurs bc of shunting through the VSD increased pulmonary venous return and mitral regurgitation. *clinical manifestations: PAVC defects are generally asymptomatic. PE- similar to secundum ASD with addition of holosystolic, regurgitant murmur of mitral regurgitation at the apex. 4-12wks of age (pulmonary vascular resistance drops) children with CAVC usually begin to show symptoms. PE- similar to VSD with addition of holosystolic murmur radiating to the back and apex, reflecting mitral valve regurgitation. mid diastolic rumble at left lower sternal border or apex reflects relative stenosis of the mitral or tricuspid valve from increased flow. infants with CAVC may have signs of HF and frequent respiratory tract infections.

Patent ductus arteriosus (PDA) p.1202-1204

-Defects Increasing Pulmonary Blood Flow -Failure of this to close -Normally closes within 15 hours to 2 weeks after birth -allows blood to shunt from the pulmonary artery to the aorta. -Vessel located between the junction of the main and left pulmonary arteries and the lesser curvature of the defending aorta, usually just distal to the left subclavian artery -during fetal circulation, this allows blood to shunt from the PA to the aorta -at birth, once the placenta is removed and the lungs are expanded, this will start to constrict within the first hours of life -closure of this in full-term infants is usually noted between 15 hours of life and 2 weeks of age -as an isolated defect, this occurs in 5-10% of all congenital cardiac defects -high in premature infants. *patho: -failure of this to close results in persistent patency of the ductus arteriosus -hemodynamics effects of this depend on the size of the lumen and the resistance in the pulmonary and systemic circulations -at birth the pulmonary and systemic vascular resistance are almost equal and are reflected in the PA and aorta, therefore shunting is minimal -as pulmonary vascular resistance falls, a reversal of fetal shunting occurs -blood now begins to shunt L to R from the aorta to the PA -hemodynamics effect is increased pulmonary blood flow, resulting in increased pulmonary venous return to the LA and LV with increased workload on the left side of the hart -the increased workload is caused by increased pulmonary venous return to the LA and an increase in right ventricular pressure if pulmonary vascular changes occur in response to the increased blood flow, leading to an increase in pulmonary vascular pressure. if pulmonary vascular resistance has fallen, PDA will have continuous machinelike type murmur- heard best at left upper sternal border throughout systole/diastole. if PDA is significant- infant will have bounding pulse, active precordium, thrill upon palpation, and s/s pulmonary overcirculation. infants with small PDA will usually remain asymptomatic.

Myocardial ischemia p 1153/1154

-Develops if the supply of coronary blood cannot meet the demand of the myocardium for oxygen and nutrients. -Stable angina: Causes predictable chest pain. -Prinzmetal angina (variant): Causes unpredictable chest pain. -Silent ischemia: Causes no detectable symptoms. -Angina pectoris: Causes transient substernal chest discomfort. *patho: The coronary arteries normally supply blood flow sufficient to meet the demands of the myocardium as it labor so under varying workloads - oxygen extraction from these vessels occurs with maximal efficiency -if efficient exchange does not meet myocardial oxygen needs, healthy coronary arteries are able to dilate to increase the flow of oxygenated blood to the myocardium -narrowing of a major coronary artery by more than 50% impairs blood flow sufficiently to hamper cellular metabolism under conditions of increased myocardial demands -myocardial ischemia develops if the supply of coronary blood can't meet the demand of the myocardium for oxygen and nutrients -imbalances bw myocardial demand and coronary blood supply can result from a number of conditions -common causes of increased myocardial demand for blood include tachycardia, exercise, hypertension (hypertrophy), and vascular dz -the most common cause of decreased coronary blood flow and resultant this is the formation of atherosclerotic plaques in the coronary circulation -as the plaque increases in size, it may partially occlude the vessel lumina, thus limiting coronary flow and causing ischemia esp during exercise -some plaques are unstable meaning they are prone to ulceration or rupture -when this ulceration or rupture occurs, underlying tissues of the vessel wall are exposed, resulting in platelet adhesion and thrombus formation -thrombus formation can suddenly cut off blood supply to the heart muscle, resulting in acute this and if the vessel obstruction cannot be reversed rapidly, ischemia will progress to infarction -this also can result from other causes of decreased blood and oxygen delivery to the myocardium, such as coronary spasms, hypotension, dysrythhmias, and decreased oxygen carrying capacity of the blood (anemia, hypoxemia). -myocardial cells become ischemic within 10 seconds of coronary occlusion -after several minutes the heart cells lose the ability to contract, and cardiac output decreases -ischemia also causes condition abnormalities that lead to changes in the ECG and may intimate dysrythmias -anaerobic processes take over and lactic acid accumulates -cardiac cells remain viable for approx 20 minutes under ischemic conditions -if blood flow is restored, aerobic metabolism resume, contractility is restored and cellular repair beings. -if the coronal after occlusion persists beyond 20 minutes, MI occurs. *clinical manifestations: Chronic coronary obstruction usually results in recurrent predictable chest pain called stable angina. abnormal vasospasm of coronary vessels results in unpredictable chest pain called prinzmetal angina. Myocardial ischemia that does not cause detectable symptoms is called silent ischemia. -stable angina: Chest pain caused by myocardial ischemia- Gradual luminal narrowing and hardening of the arterial walls, vessels cannot dilate in response to extreme myocardial demand. Associated with exertion or stress. If demand is decreased no necrosis of myocardial cells results. Angina pectoris- transient substernal chest discomfort and sensation of heaviness or pressure to moderately severe pain. often described as sensation by clenching a fist over the left sternal border. Maybe mistaken for indigestion. caused by buildup of lactic acid or abnormal stretching of ischemic myocardium that irritates myocardial nerve fibers. pain may radiate to the next lower jaw, left arm, left shoulder, or occasionally the back or down the right arm. pallor, diaphoresis, dyspnea, maybe associated. Usually relieved by rest and nitrates- lack of relief indicates individual may be developing infarction. Common symptoms in women are atypical chest pain, palpitations, sense of unease, and severe fatigue. Older adults or those with diabetes angina may be mild, atypical, or even silent. -prinzmetal angina: (variant angina) chest pain attributable to transient ischemia of the myocardium that occurs unpredictably and almost exclusively at rest. pain caused by vasospasm of one or more coronary arteries with or without associated atherosclerosis. may result from decreased vagal activity, hyperactivity of the sympathetic nervous system, and decreased nitric oxide activity. other causes include altered calcium channel function in arterial smooth muscle and endothelial dysfunction with release of inflammatory mediators (serotonin, histamine, endothelin, or thromboxane)- serum markers of inflammation may be elevated. often occurs at night during REM sleep and may have cyclic pattern of occurrence. if spasm persists, infarction or serious dysrhythmias may occur. -silent ischemia and mental stress: non specific symptoms such as fatigue, dyspnea or feeling unease. some may only have silent and some may have both silent and angina. silent/atypical symptoms are more common in women. may also occur during mental stress- increased markers of inflammation, decreased activities of vasodilators. detection is important b/c it is an indicator of increased risk for serious cardiovascular disease events, aggressive treatment may be indicated.

Heart failure p.1200/1201

-Is a common condition associated with congenital birth defects. -Neurohumoral and hemodynamic changes create abnormal ventricular wall stress and cause the myocardium to hypertrophy. -Sometimes called congestive heart failure is classified as an acquired condition -Occurs when the heart is unable to maintain sufficient cardiac output to meet the metabolic demands of the body -can occur as the result of decreased myocardial function or excessive metabolic demands -the most common causes in infancy and childhood are cardiomyopathy or the result of poor ventricular function -Pulmonary over circulation from large left-to right shunts (mixing) is often called this but is not usually associated with decreased ventricular function and failure to meet metabolic demands. -clinical manifestations are similat (FTT), tachypnea, tachycardia, respiratory tract infections. *Patho: -children/infants is very similar to adults -same compensatory mechanisms are activated in the face on inadequate cardiac output -an acute decrease in BP stimulates stretch receptors and baroreceptors in the aorta and carotid arteries, which in turn stimulate the sympathetic nervous system -with the release of catecholamines and the stimulation of B receptors, heart rate and the force of myocardial contraction increase -venous smooth muscle tone also increase, which increases return of venous blood to the heart -sympathetic stimulation also decreases blood flow to the kidneys, skin, spleen, and extremities so that maximum flow to the brain, heart and lungs can be maintained -decreased blood flow to the kidneys causes the release of renin, angiotensin, and aldosterone -if chronic, this cycle results in retention of sodium and fluid by the kidneys, which in turn increases volume in the circulatory system. -neurohumoral and hemodynamics changes create abnormal ventricular wall stress and cause the myocardium to hypertrophy -the myocardial fibers also stretch temporarily increase contractility and hence the force of ventricular contraction -these mechanisms eventually fault to maintain cardiac output as this progresses -Frank-Starling law of the heart for cycle of compensation and de compensation that occurs in this. *congenital heart defects causing heart failure Table 33-5 p.1201 -time of birth: hypo plastic left heart syndrome, volume overload caused by tricuspid regurgitation (rare), arteriovenous fistula -birth to 1 week: hypo plastic left heart syndrome, aortic atresia, transportation of the great vessels with ventricular septal defect, coarctation of the aorta, total anomalous pulmonary venous connection with obstruction, patent ductus arteriousus in premature infants -first 4 weeks: coarctation of the aorta, TAPVC, large left-to-right shunt caused by VSD, PDA in premature infants, tricuspid atresia, all previous mentioned defects 4-6 weeks: transposition of the great vessels with VSD, large left-to-right shunt caused by endocardial cushion defect 6 weeks - 6 months VSD 6 months: endocardial fibroblast oasis, persistent truncus arteriousus with large left-to-right shunt. *clinical manifestations: not necessary to determine if it is right or left sided HF. combination of symptoms is generally present- pulmonary overcirculation is the predominant cause a/w congenital defects. manifested as poor feeding and sucking, leading to FTT, dyspnea, tachypnea, and diaphoresis, may be accompanied by retractions, grunting, and nasal flaring. **wheezing, coughing, and rales are rare even when significant HR occurs. skin- pallor or mottling. hepatomegaly (attributed to venous congestion). infants with normal liver is soft, sharp edged, and palpable 1-2cm below costal margin. however, absence of hepatomegaly does not rule out HF. periorbital edema and weight gain w/o caloric increase are uncommon of right ventricular failure in infants. peripheral edema is common in adults but rare in infants/children- more often signifies renal disease rather than cardiac. cardiac manifestations HF Box 33-2 p.1202

Transposition of the great arteries (TGA) p 1214

-Mixed defect -Aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle. -the result is two separate, parallel circuits in which unoxygenated blood circulates continuously through the systemic circulation and oxygenated blood circulates repeatedly through the pulmonary circulation -incompatible with extra uterine life unless a communication exists between the two circuits to provide the necessary oxygen to the body -communication is accomplished by mixing of pulmonary and systemic circulations through a PDA, ASD, or VSD -dextro is the most common cyanotic CHD and accounts for 10% of all CHDs, refers to the aorta remaining to the right of the PA. -two factors allow newborns with complete to survive long enough to be treated -1) blood from the two closed systems can mix through the ductus arteriosus for a short time after birth if pulmonary vascular resistance remains high -some mixing also may occur through the foramen ovals -if the child has a VSD, mixing occurs through that opening as well. *patho: -not known precisely which embryologic events lead to this but researchers have proposed that th fault lies in the development of clonal tissue in the fibrous skeleton of the heart -the conus is a segment of muscle that separates the AV (tricuspid and mitral) valves from the semilunar (aortic and pulmonic) valves -the interventricular septum is intact in about 60% of cases; a VSD is present in the remaining 40% -PS is associated with this in about 4-6% of children with intact septa and in 28-31% of chidlren with VSDs. *clinical manifestation: cyanosis may be mild shortly after birth and worsen during the first day. Low oxygen levels in the blood (hypoxemia) causes metabolic acidosis, tachycardia, and tachypnea. The presence of a PDA or large ASD allows for more mixing and results in only mild cyanosis but the infant may develop CHF. The first heart sound is normal and the second sound may be heard as a single sound even though both the aortic and pulmonic valves are functioning. the loud single S2 may occur because transposition places the aortic valve closer to the chest wall then the pulmonic valve. No murmurs noted with transposition of the great arteries with an intact ventricular septum.

Aortic stenosis (AS) p.1212

-Obstructive Defects -Causes an increased workload on the left ventricle -Narrowing of the aortic outflow tract -lesion accounts for 5% of all congenital heart defects -valvular stenosis is caused by malformation of fusion of the cusps -most common type, tends to be progressive, and in rare cases, can lead to sudden death as a result of low cardiac output or myocardial ischemia -children with mild, no exercise restrictions may be needed -moderate - some exercise limitations may be advised -severe is an indication for limiting exercise until the repair is accomplished -less common forms are subvalvular stenosis caused by a constricting fibrous ring below the valve and supravalvular stenosis that occurs above the valve. *patho: -obstruction to blood flowing out of the aorta causes in increased workload on the LV, resulting in left ventricle hypertrophy -LV failure may develop, leading to an increase in LA pressure and a backup in the system, eventually resulting I pulmonary vascular congestion and pulmonary anterior hypertension -LVH can decrease coronary artery perfusion, resulting in myocardial ischemia, and it can alter the LV papillary muscle causing mitral insufficiency. *clinical manifestations: Most children with mild to moderate AS are asymptomatic. signs of exercise intolerance may not appear until preadolescents. syncopal episodes, epigastric pain, and exertional chest pain may occur in more severe forms of AS. A systolic ejection murmur at the right upper sternal border that transmits to the neck and left lower sternal border is produced by blood flow through the stenotic area. An ejection click may be heard with valvular AS. severe forms of AS, especially critical AS in the newborn result in shock and require immediate intervention.

Coarctation of the aorta (CoA) p.1210-1212

-Obstructive Defects -Narrowing of the lumen of the aorta that impedes blood flow -8-10% of all congenital heart defects -almost always in juxtaductal position, although it can occur anywhere between the origin of the aortic arch and the bifurcation of the aorta in the lower abdomen -50% of individuals with this have a bicuspid aortic valve. *patho: -may develop bc of abnormal contractile ductal tissue that constricts at the time of ductal closure -causes a condition in which there are higher pressures proximal to the site of stenosis and low pressures distal to the site -in preductal, the RV acts as a systemic pump, sending unoxygenated blood through the ductus into the descending aorta below this -in postductal, the RV can't pump enough blood through the ductus to the descending aorta bc of pressure caused by the narrowed aorta -systolic pressure increases in the ascending aorta and LV and decreases in the descending aorta beyond this -in long-standing, collateral circulation which involves small arteries arising from the subclavian arteries, joined inter coastal arteries that flow into the descending aorta -these collateral vessels bypass this and supply blood to the lower extremities -the direction of shunting through the ductus, depends on the pressure difference between the PA and aorta and the location of the ductus -when BP is greater in the aorta than in the PA, blood flow through the ductus will be left to right toward the lungs, resulting in increased pulmonary venous return to the left side of the heart -this may place an additional strain on the LA and LV, leading to increased volume and workload -with time, LV hypertrophy develops bc of increased after load and obstruction to flow caused by the coarctation -HF also may develop. *clinical manifestations: Vary depending on the severity of the coarctation and age of presentation. Onset of symptoms depends on the timing of ductal closure after a fall in pulmonary vascular resistance, the location of COA, and the presence of associated defects. The newborn usually presents with CHF symptoms. Once the ductus closes these infants will deteriorate rapidly from the development of hypertension, acidosis, and shock. Older children may not be diagnosed until hypertension is noted. hypertension as noted in the upper extremities with decreased or absent pulses in the lower extremities. children may have cool, mottled, skin, and occasionally leg cramps during exercise. a systolic ejection murmur heard best of the left interscapular area is caused by a rapid blood flow through the narrowed area.

Pulmonary stenosis (PS) p.1213

-Obstructive Defects -Narrowing of the pulmonary outflow tract -may be in the form of abnormal thickening of the valve leaflets or narrowing of the arterial (supravalvular) or ventricular (subvalvular) side of the valve -pulmonary atresia is the severe form of this and involves complete fusion of the commissures, allowing no blood flow out of the RV to the PA. *patho: -creates resistance to blood flow from the RV to the PA -narrowed orifice (valve) produces increase resistance (after load) to ejection -in order for the RV to maintain adequate cardiac output, the myocardium hypertrophied -if the RV outflow tract obstruction is severe, blood may back up into the RA, causing dilation -this may result in reopening of the foramen ovale (allows right-to-left shunting, which is necessary for fetal circulation) with resultant unoxygenated blood shunting to the LA, causing cyanosis. *clinical manifestations: depend on the severity of PS. systolic ejection murmur at the left upper sternal border reflects obstruction to flow through the narrowed pulmonary valve. in some children a variable systolic ejection click is present with valvular stenosis at the upper left sternal border. thrill may also be palpable at the upper left sternal border. Children with moderate PS may have exertional dyspnea and fatiguability because of the inability of the body to increase pulmonary blood flow to meet demands for increased cardiac output. Severe PS will produce cyanosis and heart failure.

Hypoplastic left heart syndrome (HLHS) p.1214

-Obstructive Defects -Refers to the abnormal development of the left-sided cardiac structures, resulting in obstruction to blood flow from the LV outflow tract -involves underdevelopment of the LV, aorta and aortic arch, as well as mitral atresia or stenosis -As the ductus closes, systemic perfusion is decreased, resulting in hypoxemia, acidosis, and shock. -infants with this must have a well-functioning RV and the presence of a PDA and atrial septal communication for survival -most complex congenital heart defect. *patho: -bc of the high pressures caused by LV outflow tract obstruction, saturated blood enters the LA and mixes with desaturated blood in the RA through an atrial septal communication -blood flow follows the normal pathways through the right side of the heart -exiting the PA, the mixed-saturation blood flows through the ductus and to the descending aorta -the amount of blood flow that travels to the pulmonary and systemic circulations depends on vascular resistance in the respective systems -retrograde blood flow through the hypoplastic ascending aorta provides coronary and cerebral blood flow if there is complete aortic atresia. *clinical manifestations: Full-term and initially appear healthy. As the ductus closes, systemic perfusion is decreased resulting in hypoxemia, acidosis, and shock usually no heart murmurs are detected. the second heart sound is loud and single because of aortic atresia.

Dyslipidemia p.1149

-Strong link between lipoproteins and coronary artery disease -Abnormal concentrations of serum lipoproteins -Dietary fat packaged into chylomicrons for absorption in the small intestine -Chylomicrons: Function by transporting exogenous lipid from the intestine to the liver and peripheral cells. -Primarily contains triglyceride; triglycerides may be removed and either stored by adipose tissue or used by muscle as an energy source. -Remnant contains cholesterol, which is taken up by the liver. -Very low-density lipoproteins (VLDL): Mainly triglycerides plus a carrier protein -LDL: Mainly cholesterol plus a carrier protein Are responsible for the delivery of cholesterol to the tissues. -HDL: Mainly phospholipids plus a carrier protein Are responsible for "reverse cholesterol transport," which returns excess cholesterol from tissues to the liver, where it is eliminated as bile or converted to cholesterol-containing steroids. -Can remove excess cholesterol from arterial walls. -Is an indicator of coronary risk. -Increased LDL: Play a role in endothelial injury, inflammation, and immune responses that are important in atherogenesis. -Low levels of HDL: Are responsible for "reverse cholesterol transport," which returns excess cholesterol from the tissues to the liver. -Elevated serum VLDL (triglycerides) -Increased lipoprotein (a)

Unstable angina p. 1157

-Sudden coronary obstruction because of thrombosis formation over a ruptured atherosclerotic plaque -Most common complications Dysrhythmias, congestive heart failure, and sudden death -Form of acute coronary syndrome that results in reversible myocardial ischemia -Is reversible myocardial ischemia and a harbinger of impending infarction. -Transient episodes of thrombotic vessel occlusion and vasoconstriction occur at the site of plaque damage with a return of perfusion before significant myocardial necrosis occurs. -signals that the atherosclerotic plaque has ruptured and infarction may soon follow *patho: -occurs when fissuring or superficial erosion of the plaque leads to transient episodes of thrombotic vessel occlusion and vasoconstriction at the site of plaque damage -this thrombus is labeled and occludes the vessel for no more than 10-20 minutes, with return to perfusion before significant myocardial necrosis occurs. *clinical manifestations:presents as new onset angina, occurring at rest, or angina increasing in severity or frequency. may experience dyspnea, diaphoresis, and anxiety as angina worsens.

Cellular Injury with MI p.1158

-cardiac cells can withstand ischemic conditions for about 20 minutes before cellular death takes place -after only 30-60seconds of hypoxia, ECG changes are visible -yet even if cells are metabolically altered and nonfunctional they can remain viable if blood flow returns within 20 minutes -reports suggest pervious recurrent episodes of myocardial ischemia can result in myocyte adaptiation to oxygen deprivation and preservation of myocardium -this process called ischemic preconditioning is being studied to determine whether it has potential prophylactic or therapeutic uses. -after 8-10 seconds of decreased blood flow, the affected myocardium becomes cyan optic and cooler -myocardial oxygen reserves are used very quickly (within about 8 seconds) after complete cessation of coronary flow -glycogen stores decrease as anaerobic metabolism begins -glycolysis can supply only 65% to 705 of the total myocardial energy requirements and produces much less ATP than aerobic processes -hydrogen ions and lactic acid accumulate -because Cardinal cells are very sensitive to low cellular pH, accumulation of these products further compromises the myocardium -acidosis may make the myocardium more vulnerable to the damaging effects of lysosomal enzymes and may suppress impulse condition and contractile function, thereby leading to heart failure. -oxygen deprivation also is accompanies by electrolytes disturbances, specifically loss of K, Ca, and Mg from cells -myocardial cells deprived of necessary oxygen and nutrients lose contractility, thereby diminishing the heart's pumping ability -ischemic myocardial cells release catecholamines (epi and norepinephrine) predisposing the individual to serious imbalances of sympathetic and parasympathetic function, irregular heart beats ( dysrhythmias) and heart failure -catecholamines mediate the release of glycogen, glucose, and stores fat from body cells -plasma concentrations of free fatty acids and glycerol rise within 1 hour of having onset of acute MI -excessive levels of free fatty acids can have a harmful detergent effect on cell membranes -norepinephrine elevates blood sugar levels through stimulation of liver and skeletal muscle cells -it also suppresses pancreatic B-cell activity, which reduces insulin secretion and elevates blood glucose further -hyperglycemia is noted approximately 72 hours after an acute MI and is associated with an increased risk of death, therefore careful glucose monitoring and control after Mi is essential. -ischemic injury can be exacerbated by what is termed reperfusion injury once blood flow is restored -this process involves the release of toxic oxygen radicals, calcium flux, and pH changes that cause a sustained opening of mitochondrial permeability transition pores and contribute to resultant cellular death -therapies aimed at reducing reperfusion injury are being explored, including endovascular cooling, adenosine, atrial natriuretic peptide,, cyclosporine, nicorandil, and incretins -angiotensin II is release during myocardial ischemia and contributes to the pathogenesis of MI -first it results in the systemic effects of peripheral vasoconstriction and fluid retention -these homeostatic responses are counter productive in that they increase myocardial work and this exacerbate the effects of the loss of myocyte contractility -angiotensin II is also released locally where it is a growth factor for vascular smooth muscle cells, myocytes and cardiac fibroblasts; promotes catecholamines release, and causes coronary artery spasm.

Myocardial infarction p. 1157 & 1160

-majority of cases, the decrease in coronary flow is the result of atherosclerotic CAD, other causes include coronary spasm and coronary artery embolism -pathologically there are two major types of this: sub endocardial.infarction and transmural infarction -clinically this is categorized as non-STEMI or STEMI *patho: -plaque progression, disruption, and subsequent clot formation is the same for myocardial infarction as it is for unstable angina -the thrombus is less labeled and occludes the vessel for a prolonged period, such that myocardial ischemia determines the size and character of the infarction -if the thrombus breaks up before complete distal tissue necrosis has occurred the infarction will involve only the myocardium directly beneath the endocardium (sub endocardial) -this infarction usually presents with ST depression and T wave inversion and is termed non-STEMI -important to recognize this form of acute coronary syndrome bc recurred clot formation on the disrupted atherosclerotic plaque is likely to occur unless some intervention is undertaken asap -if the thrombus lodges permanently in the vessel, the infarction will extend through the myocardium all the way form endocardium to epicardium (transmural), resulting in severe cardiac dysfunction -transmural usually causes marked elevations in ST segments on EKG -categorized as STEMI -clinically important to identify those with STEMI because they are highest risk for serious complications and require immediate intervention. *clinical manifestations: first symptom is usually sudden, severe chest pain. not possible to distinguish between angina and MI by symptoms alone. heavy, crushing, "elephant sitting on chest". radiation to jaw, back, neck, shoulder, or left arm. older adults esp diabetes, experience no pain- silent infarction. sensation of unrelenting indigestion. nausea/vomit may occur- reflex stimulation of vomiting centers by pain fibers. vasovagal reflexes also effect GI tract. cardiovascular changes on PE- SNS reflexivity, elevated HR and BP, severe damage may also cause hypotension. extra heart sound- LVD. cardiac murmurs- acute valvular insufficiency. pulmonary findings- dullness to percussion, inspiratory crackles at lung bases if HF. peripheral vasoconstriction- skin cool and clammy. ?? -Prolonged ischemia causes irreversible damage to the heart muscle (myocyte necrosis). -Cellular injury, leading to cellular death -Structural and functional changes -Myocardial stunning: Is the temporary loss of contractile function that persists for hours to days after perfusion has been restored. -Hibernating myocardium: Tissue that is persistently ischemic undergoes metabolic adaptation to prolong myocyte survival. -Remodeling: Process that occurs in the myocardium after an MI. -Repair -When coronary blood flow is interrupted for an extended period, myocyte necrosis occurs -results in this -most common complication is dysrhythmias -Angiotensin II effects -Systemic effects: Peripheral vasoconstriction and fluid retention -Myocardial work increases; thus the effects of the loss of myocyte contractility are exacerbated. -Local effects: Growth factor for vascular smooth muscle cells, myocytes, and cardiac fibroblasts; promotes catecholamine release; causes coronary artery spasms Involved in myocardial remodeling -Causes myocyte hypertrophy, scarring, and loss of contractile function in the areas of the heart distant from the site of the infarction. -Two major types -Subendocardial infarction -Transmural infarction -Individuals at highest risk for complications -ST segment elevations (STEMI) on the ECG requires immediate intervention. -Smaller infarctions are not associated with ST segment elevations (non-STEMI) -Suggest that additional myocardium is still at risk for recurrent ischemia and infarction. -Complications: Dysrhythmias, Cardiogenic shock, Pericarditis, Dressler (postinfarction) syndrome, Organic brain syndrome

Rheumatic Fever p. 1171-1172

-rheumatic fever is a systemic, inflammatory disease caused by a delayed immune response to infection by group A beta-hemolytic streptococci -acute form, is a febrile illness characterized by inflammation of the joints, skin, nervous system and heart. -if untreated, it can cause a scarring and deformity of cardiac structures resulting in rheumatic heart disease (It may have a genetic component.) ??-Abnormal immune response to the M proteins that cross react with normal tissues -Fibrinoid necrotic deposits: Aschoff bodies -crowding and poor hygiene are risk factors. -occurs most often in children between 5-15 -bc beta-hemolytic streptococcus infection must persist for some time to cause this, appropriate antibiotic therapy given within the first 9 days of infection usually prevents it -invitation of abx 2 weeks after the start of streptococcal infection doesn't prevent this in susceptible individuals. -tends to run in families, concept of genetic predisposition, including changes in major histocompatibility antigens -peple who have experiences one attack are more susceptible than the general pop to recurrent attacks. -can develop only as a sequel to pharyngeal infection by group A beta-hemolytic streptococci -streptococcal skin infections do not progress to this bc the strains of the microorganism that infect the skin do not have the same antigenic molecules in their cell membranes as do those that cause pharyngitis and therefore don't elicit the same kind of immune response -both skin and pharyngeal infections can cause acute glomerulonephritis. -affects the heart, joints, CNS, and skin through an abnormal humoral and cell mediated immune response to the M proteins on the microorganism that cross-react with normal tissues -antibodies against a strop toxic bacterial wall angigen display cross-reactivity against laminin, a protein in extracellularly tissues around heart tissue and in the valves, -cardiac myosin is another target antigen -antobdies also cross react within neuronal cells triggering dopamine release -these antibodies also affect skin, muscles, and synovial joints. -autoimmunity and associated intense inflammation result in diffuse, proliferative, and exudative lesions in the connective tissue esp in the heart, joints and skin -the inflammation may subside before tx, leaving behind damage to the heart valves and increasing the individuals susceptibility to recurrent his after any subsequent end streptococcal infections -repeated attacks of this cause chronic proliferative changes in the previously mentioned organs as a result of scarring, granulomas, and thromboses. -approx 10% of cases develop RHD -several genes have been implicated in RHD,including the HLA-DR 1 antigen and HLA-DR 6 antigen, which suggests that genetically determined immune response factors may play a role in the pathogenesis of severe chronic RHD -RHD begins as carditis, or inflammation of the heart -although this can cause carditis in all three layers, of the heart wall, (endo, myo and pericardium) the primary lesion usually involves the endocardium, which include the heart valves -endocardial inflammation causes swelling of the valve leaflets, with secondary erosion along the lines of leaflet contact -small bead like clumps of vegatation containing platelets and fibrin are deposited on eroded valvular tissue and on the chordae tendineae -the chordae tendineae anchor the valve leaflets -the valves lose their elasticity and the leaflets may adhere to each other -scarring and shortening of the involved structures occur over time -in inflammation penetrates the myocardium, localized fibrin deposits develop that are surrounded by area of necrosis -these fibrinoid necrotic deposits are called Aschoff bodies -pericardial inflammation is usually characterized by serofibrinous effusion within the pericardial cavity. *clinical manifestations: common symptoms are fever, lymphadenopathy, arthralgia, nausea, vomiting, epistaxis (nose bleed), abdominal pain, tachycardia. major manifestations- carditis p.1172, migratory polyarthritis p.1172, chorea (sydenham chorea or st, vitus dance) p.1172, erythema marginatum p.1172

Infective Endocarditis p. 1173 & 1175

?? -Pathogenesis: Endocardial damage, blood borne microorganism adherence, Formation of infective endocardial vegetations. -risk factors: acquired valvular heart disease (esp mitral valve prolapse), implantation of prosthetic heart valves, congenital lesions assoc with highly turbulent flow (ventricular septal defect), previous attack of this, IV drug use, long term indwelling IV catherization (for pressure monitoring, feeding, hemodialysis), implantable cardiac pacemakers, and heart transplant with defective valve. -A general term used to describe infection and inflammation of the endocardium from infectious agents, esp in cardiac valves. -bacteria are the most common cause esp streptococci, staphylococci, and enterococci -other causes include viruses, fungi, rickettsia, and parasites *patho: -three critical elements for patho 1) endocardial damage. -trauma, congenital heart disease, valvular heart dz, and the presence of prosthetic valves are the most common risk factors for endocardial damage that leads to this -turbulent blood caused by these abnormalities usually affects the atrial surface of atrioventricular valves or the ventricular surface of semilunar valves -endocardial damage exposes the endothelial basement membrane, which contains a type of collagen that attracts platelets and thereby stimulates sterile thrombus formation on the membrane -this causes an inflammatory reaction (nonbacterial thrombotic endocarditis) 2) blood borne microorganisms adherence to the damaged endocardial surface. -Bacteria may enter the blood stream during injection drug use, trauma, dental procedures that involve manipulation of the gingiva, cardiac surgery, genitourinary procedures, and indwelling catheters in the presence of infection, or GI instrumentation, or the may spread from uncomplicated upper respiratory or skin infections -bacteria adhere to the damaged endocardium using adhesions 3) formation of infective endocardial vegetations. -bacteria infiltrate the sterile thrombi and accelerate fibrin formation by activating the clotting cascade -these vegetative lesions can form anywhere on the endocardium but usually occur on heart valves and surrounding structures -although endocardial tissue is constantly bathed in antibody--containing blood and is surrounded by scavenging monocytes and polymorphonuclear leukocytes, bacterial colonies are inaccessible to host defenses because they are embedded in the protective fibrin clots -embolization from these vegetations can lead to accesses and characteristic skin changes, such as petechiae, splinter hemorrhages, Osler nodes, and Janeway lesions. *clinical manifestations: may be acute, sub acute, or chronic. causes varying degrees of valvular dysfunction and may be associated with manifestations involving several organ systems (lungs, eyes, kidneys, bones, joints, CNS)- dx difficulty. s/s are caused by infection and inflammation, systemic spread of microemboli, and immune complex deposition. classic findings- fever, new/changed murmur, petechial lesions of the skin, conjunctiva and oral mucosa. PE- Osler nodes (painful erythematous nodules on the pads of the fingers and toes) and janeway lesions (non-painful hemorrhagic lesions on the palms and soles). other s/s- weight loss, back pain, night sweats, HF, CNS, splenic, renal, pulmonary peripheral arterial, coronary and ocular emboli lead to variety of s/s. sudden onset severely debilitating symptoms indicate acute disease.

Cellular Death in MI p. 1159

After about 20 minutes of myocardial ischemia, irreversible hypoxia injury causes cellular death and tissue necrosis -necrosis of myocardial tissue results in the release of certain intracellular enzymes through the damaged cell membranes into the interstitial spaces -the lymphatics pick up the enzymes and transport them into the blood stream, where they can be detected by serologic tests -tissue is also destroyed by the tightly controlled process of apoptosis.

Dysrythmias p 1182

Can be caused by an abnormal rate of impulse generation or an abnormal impulse conduction. This or arrhythmia is a disturbance of heart rhythm -normal heart rhythms are generated by the SA node and travel through the heart's conduction system, causing the atrial and ventricular myocardium to contract and relax at a regular rate that is appropriate to maintain circulation at various levels of physical activity -range in severity from occasional "missed" or rapid beats to serious disturbances that impair the pumping ability of the heart, contributing to heart failure and death -can be caused by either an abnormal rate of impulse generation by the SA node or other pacemaker of the abnormal conduction of impulses through the hearts conduction system including the myocardial cells themselves

Chronic orthostatic hypotension p.1140

Categorized as 1) secondary to a specific dz and 2) idiopathic or primary -the dz that cause secondary are endocrine disorders (adrenal insufficiency, diabetes) metabolic disorders (porphyria), or dz of the central or peripheral nervous system (intracranial tumors, cerebral infarcts, Wernicke encephalopathy, peripheral neuropathiies) -cv autonomic neuropathy is a common cause in DM and is a serious and often overlooked complication -severe chronic autonomic failure may result from multiple system atrophy, in which there are multiple central nervous system degenerative changes and Parkinson's dz -inviduals with these disorders also may exhibit supine, hypertension, altered drug sensitivity, hyperresponsibveness of blood pressure to hyp/hyperventilation, sleep apnea and other neurological disturbances

Sinus block

Disorder of impulse conduction Occasionally absent P wave associated with a loss of QRS complex for that beat -occasional decrease in cardiac output -increase in preload for the following beat -local hypoxia, scarring of intra-atrial conduction pathways, electrolyte imbalances Increased atrial preload

Third degree block

Disorder of impulse conduction P waves present and independent of QRS No observed relationship between P and QRS Always AV dissociation present -same effect as idiojunctional rhythm -Hypokalemia (<3.5) Faulty cell metabolism low in bundle of His MI, esp inferior wall as nodal artery interrupted, results in ischemia of AV node

Atrioventricular dissociation

Disorder of impulse conduction P waves present and independent of QRS, but not always because of block (ventricular tachy) Not always third block -decreased CO from loss of atrial contribution to ventricular preload Variable effect on myocardial demand depending on ventricular rate May result from third-degree block or accelerated junctional or ventricular rhythm or be caused by sinus, atrial and junctional bradycardia a

First degree block

Disorder of impulse conduction PR interval >0.2 No effect Same Patho as sinus block Hypercalcemia (>7), Hypokalemia (<3.5), formation of myocardial abscesses in endocarditis

Second degree block, Mobitz 1, or Wenckebach

Disorder of impulse conduction Progressive prolongation of PR interval until one QRS is dropped Pattern of prolongation resumes Same effect as sinus block Hypokalemia (<3.5) Faulty cell membrane in AV node Severity increases as heart rate increases Supports theory that AV node is fatiguing Digoxin toxicity, beta blockade Coronary artery dz, MI, hypoxia, increased preload, valvular surgery and dz, diabetes

Aberrant conduction

Disorder of impulse conduction QRS >0.11 No effect unless ventricular rate abnormalities present Conduction of impulse through intercalated disks because conduction system transiently blocked because of hypoxia, electrolyte imbalances, digoxin toxicity, excessively rapid rates of discharge

Ventricular block

Disorder of impulse conduction QRS >0.11, RSR in v1, v2, v5, v6 No effect Faulty cell metabolism in right and left bundle branches RBBB more common the LBBB because of dual blood supply to left bundle branch Congestive heart failure, mitral regurgitation, esp anterior MI bc of infarct of fascicles Left anterior he block more common than left posterior hemiblock, since posterior fascicles have dual blood supply

Second-degree block or Mobitz II

Disorder of impulse conduction Same ECG pattern as sinus block Same effect as sinus block Hypokalemia (<3.5) Faulty cell metabolism below AV node Anti dysrhythmics, cyclic antidepressants CAD, MI, hypoxia, increased preload, vavular surgery and dz, diabetes

Ventricular standstill or asystole

Disorder of impulse formation P absent or independent QRS absent No cardiac output Not compatible with life Profound ischemia, Hypercalcemia or acidosis

Idioventricular rhythm

Disorder of impulse formation P absent or independent QRS >0.11 and rate 20-39 Same effect as idiojunctional rhythm -sinus, atrial and junctional bradycardia, standstill or block

Ventricular bradycardia

Disorder of impulse formation P absent or independent QRS >0.11 and rate 60-21 Effect is same as idiojunctional rhythm Path is same too

Premature atrial contractions (PACs) or beats

Early P waves that may have changed morphology PR interval normal QRS for each P Occasionally decreased filling time and MAP Electrolyte distrubances: decrease in all phases Hypoxia and elevated preload: cell membrane disturbances Hypercalcemia Disorder of impulse formation

Premature ventricular contractions (PVCs) or depolarization

Early beats with P waves QRS occasionally opposite in deflection from usual QRS Same effect as PJCs Same Patho too, including aging and induction of anesthesia -Impulse originates in cell outside normal conduction system and spreads through intercalated disks Disorder of impulse formation -Originates outside the normal conduction system.

Premature junctional contractions (PJCs) or beats

Early beats without P waves QRS morphology normal Decreased cardiac output from loss of atrial contribution to ventricular preload for that beat Hyperkalemia (6-5.4) Hypercalcemia, hypoxia, and elevated preload (See PACs) Disorder of impulse formation

Primary Hypertension p. 1132

Hypertension: -Prehypertension: 120 to 139 mm Hg systolic; 80 to 90 mm Hg diastolic -Isolated systolic hypertension: Elevated systolic blood pressure accompanied by normal diastolic blood pressure -Consistent elevation of systemic arterial blood pressure -most common primary dx in US -sustained systolic bp of 140 or > with diastolic of 90 or > -pre are at risk for developing this and many associated cv complications. -95% of cases have no known cause and are dx as primary HTN. -Secondary Is caused by altered hemodynamics from an underlying primary disease or drugs. -Affects the entire cardiovascular system -Systolic hypertension: Most significant factor in causing target organ damage -associated with increased risk for target organ disease events such as MI, kidney dz and stroke. *Factors a/w primary HTN: -inherited defects are associated with renal sodium excretion, insulin and insulin sensitivity, activity of the sympathetic nervous system and renin-angiotensin-aldosterone system and cell membrane sodium or calcium transport -black people have variants of the apolipoporotein L1 gene that are associated with this and renal dz -risk factors: family hx, advancing age, gender (men younger than 55 and women older than 70), black race, high dietary sodium intake, glucose intolerance (DM), cigarette smoking, obesity, heavy alcohol consumption, and low dietary intake of K, Ca, and Mg. -HTN, dyslipidemia, glucose intolerance often occur together- metabolic syndrome. -low intake of K, Ca and Mg bc without them Na is retained -nicotine in cigarette smoke is a vasoconstrictor that can elevate systolic and diastolic blood pressure acutely -habitual smoking is associated with a high incidence of severe this, myocardial hypertrophy and death resulting for CAD -incidence is higher among heavy drinkers (>3 drinks per day) but moderate drinkers (2-4 per week) have the lowest average bp and cv mortality -obesity is recognized as an important risk factor even in children and adolescents. *Patho: -caused by increases in cardiac output or total peripheral resistance or both -cardiac output is increased by any condition that increases heart rate or stroke volume, whereas peripheral resistance is increased by any factor that increases blood viscosity or reduces vessel diameter (vasoconstriction) *Primary HTN: -result of a complicated interaction between genetics and the environment that increase vascular tone (increased peripheral resistance) and blood volume, this causing sustained increases in BP -multiple Pathophysiology mechanisms mediate these effects including the sympathetic nervous system, the RAAS, and natriuretic peptides -inflammation, endothelial dysfunction, obesity-related hormones, and insulin resistance also contribute to both increased peripheral resistance and increased blood volume -increased vascular volume is related to a decrease in renal excretion of salt, often referred to as a shift in the pressure-natriuresis relationship -for a given BP, individuals with this tend to secrete less salt in their urine -SNS contributes to pathogenesis of this in many people -SNS contributes to maintenance of adequate BP and tissue perfusion, in healthy people, by promoting cardiac contractility and heart rate (maintenance of adequate cardiac output) and by inducing arteriolar vasoconstriction (maintenance of adequate peripheral resistance) -with this, over activity of the SNS can result from increased production of catecholamines (epinephrine and norepinephrine) or from increased receptor reactivity involving these neurotransmitters -increased SNS activity caused increased heart rate and systemic vasoconstriction, thus raising BP, -efferent sympathetic outflow stimulates renin release, increases tubular sodium reabsorption, and reduces renal blood flow -additional mechanisms of SNS-induced this include structural changes in blood vessels (vascular remodeling), insulin resistance, increased renin and angiotensin levels and procoagulant effects -SNS is implicated in the cardiovascular and renal complications of this and new techniques such as renal denervation are being explored to treat it Figure 32-3 p. 1133 -dysfunction of adducin too - procoagulant effects and vascular remodeling lead to narrowing of vessels and vasospasm -increased insulin resistance leads to endothelial dysfunction leads to narrowing of vessels and vasospasm too. -in healthy individual- RAAS provides an important homeostasic mechanism for maintaining adequate blood pressure and tissue perfusion. -this, over activity of RAAS contributes to salt and water retention and increased vascular resistance -high levels of angiotensin II contribute to endothelial dysfunction, insulin resistance, dyslipidemia, and platelet aggregation and play an important role in the complications associated with metabolic syndrome -angiotensin II mediates arteriolar remodeling, which is structural change in the vessel wall that results in permanent increases in peripheral resistance -angiotensin II is associated with end-organ effects of this, including atherosclerosis, renal dz, and cardiac hypertrophy -aldosterone contributes to sodium retention by the kidney and also has other deleterious effects on the CV system -ACE inhibitors and ARBs oppose the activity of RAAS and are effective in reducing BP and protecting against target organ damage -second RAAS - uses ACE 2 to create Ang 1-7, which has CV protective effects -the natriuretic hormones modulate renal sodium excretion and require adequate K, Ca, and Mg to function properly -the natriuretic hormones include atrial natriuretic peptide, brain natriuretic peptide, C-type natriuretic peptide and urodilatin -these hormones induce dieresis, enhancement of renal blood flow, and glomerular filtration rate, systemic vasodilation, and suppression of aldosterone and inhibition of the SNS -dysfunction of these hormones, along with alterations in the RAA system and the SNS, cause in increase in vascular tone and a shift in the pressure-natriuresis relationship -when there is inadequate natriuretic fx, serum levels of the natriuretic peptides are increased -increased ANP and BNP levels are linked to an increased risk for ventricular hypertrophy, atherosclerosis, and heart failure -salt retention leads to water retention and increased blood volume, which contributes to an increase in BP -subtle renal injury results, with renal vasoconstriction and tissue ischemia -tissue ischemia causes inflammation of the kidney and contributes to dysfunction of the glomeruli and tubules and promotes additional sodium retention -increasing dietary intake of K, Ca, and Mg enhances natriutretic peptide fx, a drug that mimics the effect of one of these hormones (nesiritde) is used to treat heart failure -renal inflammation contributes to sodium retention -inflammation also plays a role in the vascular dysfunction of hypertension -endothelial injury and tissue ischemia result in the release of vasoactive inflammatory cytokines -although many of these cytokines have vasodilatory actions in the acute inflammatory injury, chronic inflammation contributes to vascular remodeling and smooth muscle contraction -endothelial injury and dysfunction in this is further characterized by decreased production of vasodilators, such as nitric oxide, and increased production of vasoconstrictors such as endothelin -endothelin blockade has been shown to reduce BP and prevent proteinuria -obesity is important risk factor and contributes to many of the neuro humoral, metabolic, renal and CV processes that cause -obesity causes changes in what are called the adipokines (leptin and adiponectin) and is associated with increased activity of the SNS and RAAS -obesity is linked to inflammation, small artery remodeling, endothelial dysfunction and insulin resistance and an increased risk for cardiovascular complications. -insulin resistance is common in this even in individuals without clinical diabetes -insulin resistance is associated with decreased endothelial release of nitric oxide and other vasodilators -it also effects renal function and causes renal salt and water retention -insulin resistance is associated with over activity of the SNS and the RAAS -diabetes drugs that increase insulin sensitivity often decreases BP. *clinical manifestations: early stages have no manifestations other than elevated blood pressure. lack of symptoms means the individuals less likely to seek healthcare- (lanthanic) silent killer. Likelihood to develop primary hypertension increases with age. It does occur in children and is being diagnosed with increasing frequency. If elevated blood pressure is not detected or treated, it may begin to accelerate its effect on tissues when the individual is 30 to 50 years of age which sets the stage for complications that begin to appear during the fourth, fifth, and sixth decades of life. Chronic hypertension tends to be specific to the organs and tissues affected.

Repair of MI p.1160

MI causes a severe inflammatory response that ends with wound repair -repair consist of degradation of damaged cells, proliferation of fibroblasts, and synthesis of scar tissue -many cell types, hormones, and nutrient substrates must be available for optimal healing to proceed -within 24 hours, leukocytes infiltrate the necrotic area and proteolytic enzymes from scavenger neutrophils degrade neurotic tissue -a collagen matrix is deposited and is initially weak, mushy and vulnerable to rein jury -unfortunately it is at this time in the recovery period (10-14 days after infarction) that individuals feel more capable of increasing activities and this may stress the newly formed scar tissue -after 6 weeks the neurotic area is completely replaced by scar tissue, which is strong but unable to contract and relax like healthy myocardial tissue.

Ventricular fibrillation

P absent QRS complex is characterized by a heart rate of >300 bpm and is usually not observable; is not compatible with life. -same effect as ventricular standstill -same Patho as PVCs -rapid infusion of K

Agonal rhythm/electromechanical dissociation

P absent or independent QRS >0.11 and rate 20 or less Absent or barely present cardiac output and pulse Not compatible with life Depolarization and contraction not coupled: electrical activity present with little or no mechanical activity Usually caused by profound hypoxia

Accelerated ventricular rhythm

P absent or independent QRS >0.11 and rate 41-99 Same effect as accelerated junctional rhythm Same Patho as PVCs Disorder of impulse formation

Ventricular tachycardia

P absent or independent QRS complex is >0.11 ms, with a rate of 100 bpm or more. Same effects as junctional tachycardia Same Patho as PVCs Disorder of impulse formation

Junctional tachycardia

P absent or independent QRS morphology normal, rate 100 or more -decreased cardiac output from loss of atrial contribution to ventricular preload -increased myocardial demand because of tachycardia Same Patho as PJCs Disorder of impulse formation

Accelerated junctional rhythm

P absent or independent QRS morphology normal, rate 60-99 Decreased cardiac output from loss of atrial contribution of ventricular preload -Patho same as PJCs Disorder of impulse formation

Junctional bradycardia

P absent or independent QRS normal, rate 40 or less -same effect as idiojunctional rhythm -same Patho as idiojunctional rhythm -Vagal hyperactivity Disorder of impulse formation

Idiojunctional rhythm

P absent or independent QRS normal, rate 41-59, regular Decreased cardiac output from loss of atrial contribution to ventricular preload -decrease MAP as a result of bradycardia -atrial and sinus bradycardia, standstill or block

Pre excitation syndromes (Wolff-Parkinson-White and Lown-Ganong-Levine)

P present with QRS for each P PR interval >0.12 and QRS >0.11 because of present of delta wave in PR No effect Congenital presence of accessory pathways (bundle of Kent and fiber of Mahaim) that conduct very rapidly and bypass the AV node, causing early ventribular depolarization in relation to atrial depolarization Prone (reason unknown) to tachycardias and atrial fibrillation that can result in very rapid ventricular rates Disorder of impulse conduction

Atrial tachycardia (includes premature atrial tachycardia if onset is abrupt)

P rate 151-250P morphology may differ from sinus PPR interval normal P:QRS ratio variable Decreased filling time, MAP, Increased myocardial demand Same as PACs: leads to increased atrial automaticity, atrial recently Digoxin toxicity: common Disorder of impulse formation

Atrial flutter

P rate 251-300, morphology may vary from sinus P -PR interval usually not observable -P:QRS ratio variable -decreased filling time and MAP -same as atrial tachycardia -aging

Atrial Fibrillation

P rate >300 and usually not observable No PR interval QRS rate variable and rhythm irregular Same effect as a flutter -same Patho as a tachy -aging

Myocardial remodeling p.1160

Processed mediated by angiotensin II, aldosterone, catecholamines, adenosine, oxidative stress, and inflammatory cytokines, which causes myocyte hypertrophy scarring and loss of contractile function in the areas of the heart distant from the site of infarction -these changes can be limited and even reversed (reverse remodeling) though rapid restoration of coronary flow and the use of ACE inhibitors, beta-blockers, statins, sequential pacemakers and ventricular assist devices after MI.

Sinus bradycardia

Pulse 60 beats per minute (bpm) or less PR interval normal QRS for each P Increased preload Decreases MAP Hyperkalemia, slows depolarization Vagal hyperactivity; unknown Digoxin toxicity common Late hypoxia; lack of ATP Disorder of impulse formation

Simple sinus tachycardia

Pulse rate 100 to 150 bpm PR interval normal QRS for each P Decreased filling times Decreased MAP Increased myocardial demand Catecholamines - rise in resting potential, calcium influx Fever - unknown Early failure and lung dz: hypoxic cell metabolism Hypercalcemia Disorder of impulse formation

Sinus dysrhythmias

Rate varies P-P regularly irregular, short with inspiration, long with exhalation PR interval normal QRS for each P Variable filling times, MAPS and oxygen demand Unknown Common in young children and young adults Disorder of impulse formation

Hibernating myocardium p.1160

Refers to tissue that is persistently ischemic and undergoes metabolic adaptation to prolong myocyte survival until perfusion can be restored -restoring adequate perfusion to the myocardium with revascularization therapies can improve myocardium function.

Acute orthostatic hypotension p. 1140

Temporary type -may result from: 1) altered body chemistry 2) drug action (anti hypertensives or antidepressants) 3) prolonged immobility caused by illness 4) starvation 5) physical exhaustion 6) any condition that produces volume depletion (massive dieresis, K or Na depletion) and 7) venous pooling (pregnancy, extensive varicose ties) -older adults are susceptible to this, postural reflexes are slowed as part of the aging process

dilated cardiomyopathy p. 1165, 1166

characterized by diminished myocardial contractility- diminished systolic performance of the heart. impaired systolic dysfunction leads to increases in intracardiac volume, ventricular dilation, and systolic heart failure. this is usually the result of ischemic heart disease, valve disease, diabetes, renal failure, hyperthyroidism, alcohol or drug toxicity, peripartum complications, genetic disorders, or infection. idiopathic dilated cardiomyopathy often has famililial origin (alterations in gene coding- contractile proteins, mitochondrial dysfunction, and immune defects. ischemic cardiomyopathy is most common, occurs as direct result of MI or repetitive ischemic insults in poorly controlled angina. valvular heart disease causes cardiac chamber volume and pressure overload that can result in long term myocardial dysfunction. diabetes and uremia are a/w decrease myocardial contractility and dilated cardiomyopathy, alcohol can be toxic to the myocardium as well as drugs (chemotherapeutic, inotropic, and antidysrhythmic agents. nutritional deficiencies- niacin, vit D, and selenium can cause cardiomyopathy. peripartum cardiomyopathy occurs in previously healthy women in final month of pregnancy and up to 5 months after delivery. dilated cardiomyopathies also may be late autoimmune consequences of previous viral infections resulting in myocarditis and subsequent decreases in contractility. hyperthyroidism may be present in A-fib and dilated cardiomyopathy (reversible with tx of thyroid disease). most common sx- dyspnea and fatigue. pulmonary congestion is expected, fulminant pulmonary edema is uncommon. palpitations and associated dysrhythmias may cause syncope. systemic/pulmonary emboli are common complications. chest pain may be present but usually non specific and unlike anginal pain. blood pressure may be elevated initially, hypotension indicates progression of decreased cardiac contractility. extra heart sounds, murmurs may be present. echo and MRI confirm dx.

restrictive cardiomyopathy p.1167

characterized by restrictive filling and reduced diastolic volume of either or both ventricles with normal or near normal systolic function and wall thickness. may occur idiopathically or as cardiac manifestation of systemic disease- scleroderma, amyloidosis, sarcoidosis, lymphoma, and hemochromatosis, or a number of inherited storage disease. myocardium becomes rigid and non compliant, impeding ventricular filling and raising filling pressures during diastole. over clinical/hemodynamic picture- mimics/may be confused with pericarditis. most common manifestation is right hearted failure with systemic venous congestions. cardiomegaly and dysrhythmias are common. death occurs as result of heart failure or dysrhythmias.

Heart failure p. 1175-1177

condition in which the heart is unable to generate an adequate cardiac output- there is inadequate perfusion of tissues or increased diastolic filling pressure of the left ventricle, or both, pulmonary capillary pressures are increased . ischemic heart disease and hypertension are the most important predisposing risk factors. other risk factors are age, obesity, diabetes, renal failure, valvular heart disease, cardiomyopathies, myocarditis, congenital heart disease, and excessive alcohol use. numerous genetic polymorphisms have been linked to an increased risk of heart failure, including genes for cardiomyopathies, myocyte contractility, and neurohumoral receptors. most causes of HF result in dysfunction of the left ventricle (systolic and diastolic HF). the right ventricle may also be dysfunctional, especially in pulmonary disease (right ventricular failure). *some conditions cause inadequate perfusion despite normal or elevated cardiac output (high output failure). Types: Left HF (congestive heart failure)- HF with reduced ejection fraction (systolic heart failure) or heart failure with preserved ejection fraction (diastolic heart failure), can occur together or singly. HFrEF (systolic HF)- EF <40%, inability for heart to generate adequate cardiac output (CO) to perfuse vital organs. CO depends on HR and stroke volume. stroke volume is influenced by contractility, preload, and afterload. contractility is reduced by diseases that disrupt myocyte activity (MI most common disease cause, others are cardiomyopathies or myocarditis). secondary causes (ischemia, increased myocardial workload contribute to inflammatory, immune, neurohumoral changes (activation of SNS and RAAS) that mediate ventricular remodeling. when contractility is decreased, stroke volume falls, and left ventricular end-diastolic volume (LVEDV) increases. this causes dilation of the heart and increase preload. preload and LVEDV, increases with decreased contractility or excess plasma volume (IVF administration, renal failure, MVD). increases in LVEDV can improve CO but as preload rises, myocardium stretches leading to dysfunction of sarcomeres and decreased contractility. increased afterload is most commonly result of increased peripheral vascular resistance (PVR), seen with HTN- 75% HF cases have antecedent HTN. can also be cause of aortic valve disease. increased PVR- there is resistance to ventricular emptying and and more workload for the left ventricle, which responds with hypertrophy of the myocardium. this differs from physiologic myocyte response to increased workload (exercise) because it is constant not intermittent- results in increased muscle mass but no distortion of the cardiac architecture. sustained afterload leads to pathologic hypertrophy mediated by angiotensin 2 and catecholamines. increased muscle mass- increases O2 and energy demand. myocardium consumes a huge amount of metabolic energy and relies on efficient production of ATP. production of ATP depends on the myocytes getting enough fuel, having enough mitochondrial function, and using an effective creatinine kinase system. if demand exceeds ability of these systems to supply ATP- contractility of myocardium is compromised. energy starved state further contributes to changes in myocytes and ventricular remodeling that significantly impairs contractility and therefore ventricular function. remodeling also results in deposition of collagen in btw myocytes which can disrupt integrity of the muscle, decrease contractility, and make the ventricle more likely to dilate and fail. weakness of the cardiac muscle due to HTN-induced hypertrophy is called hypertensive hypertrophic cardiomyopathy. CO falls, renal perfusion diminishes with activation of RAAS, which acts to increase PVR and plasma volume, thus increasing afterload and preload more. baroreceptors in central circulation detect the decrease in perfusion and stimulate the SNS to cause more vasoconstriction and cause the hypothalamus to produce antidiuretic hormone. *vicious cycle of decreasing contractility, increasing preload, and increasing afterload causes progressive worsening of left HF. *also characterized by a complex constellation of neurohormonal, inflammatory, and metabolic processes. catecholamines, RAAS (angiotensin 2 and aldosterone), arginine vasopressin, natriuretic peptides, inflammatory cytokines (TNF-a and IL6), myocyte calcium transport, insulin resistance and diabetes. p. 1177/1178 interaction results in gradual decline in myocardial function- changes in myocyte myofilaments, decreased contractility, myocyte apoptosis and necrosis, abnormal fibrin deposition in the ventricle wall, myocardial hypertrophy and changes in ventricular chamber geometry. these changes reduce myocardial function and CO- lease to morbidity and mortality.

cardiomyopathies p.1165

group of disease that effect the myocardium. most result from remodeling r/t neurohumoral responses to ischemic heart disease or hypertension on the heart muscle. also r/t inherited disorders, infectious disease, exposure to toxins, systemic connective tissue disease, infiltrative and proliferative disorders, or nutritional deficiencies. many cases are idiopathic. cardiomyopathies are categorized as dilated, hypertrophic, or restrictive depending on tissue characteristics, genomics, and hemodynamic effects. individual may display characteristics or more than one type.

hypertrophic cardiomyopathy p.1166, 1167

refers to two major categories of thickening of the myocardium- hypertrophic obstructive cardiomyopathy (asymmetric septal hypertrophic cardiomyopathy or subaortic stenosis) and hypertensive or valvular hypertrophic cardiomyopathy (very different). hypertrophic cardiomyopathy most common inherited heart defect (autosomal dominant). characterized by thickening of septal wall which causes outflow obstruction to the left ventricle outflow tract. other changes- abnormalities of collagen deposition and altered contractile proteins in the myocytes. thickening results in hyperdynamic state- esp with exercise. diastolic relaxation is impaired and ventricle compliance is decreased. individuals c/o angina, syncope, palpitations, and symptoms or MI and left heart failure. P/E- reveals extra heart sounds and murmurs, echo and cardiac cath confirm dx. this kind of cardiomyopathy is a significant risk for serious ventricular arrythmias and sudden death. hypertensive or valvular hypertrophic cardiomyopathy occurs b/c increased resistance to ventricular ejection. commonly seen in HTN or valvular stenosis (usually aortic). hypertrophy of the myocytes is an attempt to compensate for increase myocardial work load. long term dysfunction of myocytes develops over time, first diastolic dysfunction eventually leads to systolic dysfunction of the ventricle. individuals may be asymptomatic or c/o angina, syncope, dyspnea on exertion, and palpitations. PE- extra heart sounds and murmurs, echo and cath confirm dx.

ventricular remodeling p. 1175

results in disruption of the normal myocardial extracellular structure with resultant dilation of the myocardium and causes progressive myocyte contractile dysfunction over time.