WCU Study Review 3: Ch. 16, 18, 19, 20

What is the marker of choice for detecting a myocardial infarction?

Two proteins that make up part of the cardiac cell contractile apparatus, troponins I and T, have become the markers of choice for detecting MI. Cardiac troponin levels become elevated in serum at about the same time as CK-MB, but they remain elevated for a longer period. ST-segment elevation is thought to represent acute cell injury and ischemia. An elevated level of serum CK-MB is a highly specific indicator of MI and considered to be diagnostic. However, CK-MB remains elevated for only 48 to 72 hours after MI. Cardiac myoglobin levels are elevated in serum very quickly after MI and may be helpful in early detection; however, cardiac myoglobin is less specific than the other markers.

Which statement is true about baroreceptors?

An increase in pressure (MAP) causes an increase in discharge of the baroreceptors. An increase in firing of the baroreceptors causes a decrease in sympathetic outflow. Baroreceptors alter CO and SVR. Changes in MAP affect the baroreceptors. Baroreceptors are located in the carotid sinus and arch of the aorta.

Atherosclerosis predisposes to a number of processes that are factors in myocardial ischemia. These processes include

Atherosclerotic plaques with large lipid cores are fragile and prone to rupture. Rupture of a plaque exposes subendothelial proteins and initiates platelet aggregation and thrombus formation. Hemorrhage can lead to hemorrhagic shock, but death is not directly related to either atherosclerosis or myocardial ischemia, but rather hypovolemia. Coronary dilation would not hinder blood flow which is a cause of myocardial ischemia. Ventricular dysrhythmia affects cardiac conduction and function, but these dysfunctions are not related to atherosclerosis or myocardial ischemia.

Atrial fibrillation is best described as when

Atrial fibrillation is described as disorganized and irregular atrial waves accompanied by an irregular ventricular rate. Escape rhythms can present with a P wave that precedes, follows, or is buried in the QRS complex. Atrial flutter is typically manifested by a rapid atrial rate of 240 to 350 beats/min and a characteristic saw-tooth pattern of atrial depolarizations. Premature atrial complexes (PAC) are characterized by P waves that occur earlier than normal, preceded by a P wave with a normal QRS configuration.

Circulatory shock is best defined as

Circulatory shock is characterized by an imbalance between oxygen supply and oxygen requirements at the cellular level, wherein oxygen supply is decreased. Circulatory shock and acute pump failure are not the only causes of cardiovascular collapse. Vasodilation is not a cause of cardiovascular collapse, but is seen in anaphylactic, neurogenic, and septic shocks.

Tetralogy of Fallot is characterized by which of the following? (Select all that apply.)

Defining features of tetralogy of Fallot are ventricular septal defect, right ventricular hypertrophy, pulmonary stenosis that obstructs right ventricular outflow, and an aorta positioned above the ventricular septal opening (overriding aorta). Transposition of the great arteries is not a defining feature of tetralogy of Fallot

Cardiac output is the product of both

The product of stroke volume and heart rate provides the amount of cardiac output. None of the other options (MAP, SVR, or pulse pressure) are factors in cardiac output.

Which diagnostic analysis is used to identify patients with heart failure? (Select all that apply.)

BNP is a blood test that assists in identifying patients with heart failure. An echocardiogram uses sound waves to create a moving picture of the heart and is used in the diagnosis of heart failure. A chest x-ray is a physical diagnostic test that shows heart structures and is used in the diagnosis of heart failure. Complete blood count (CBC) is a blood analysis used to determine the composition of blood related to amounts of specific cells in a serum sample. The overall effect of ANP on the body is to counter increases in blood pressure and volume caused by the renin-angiotensin system.

Which statement is true regarding hypertension during pregnancy?

CO decreases by 40% to 60% during the first two trimesters of pregnancy. Only 12% to 22% of pregnancies are complicated with hypertension. Blood pressure normally decreases during the first two trimesters and gradually returns to normal levels during the third trimester. Serious side effects of hypertension, including seizure, fetal death, and maternal death, can occur during pregnancy.

A patient is admitted to the hospital with left-sided heart failure. Which clinical manifestation would the nurse expect the client to exhibit? (Select all that apply.)

Common clinical manifestations of left-sided heart failure include cough, dyspnea, and crackles in lungs upon auscultation. Bradypnea describes abnormal slowness of breathing not seen in left-sided heart failure. Peripheral edema is associated with right-sided heart failure.

Abnormal vascular regulation by endothelial cells in small vessels of the heart contributes to

Endothelial cells are important regulators of vascular tone. They secrete variable amounts of constricting and relaxing factors to control tissue perfusion. Hypertension is a result of a variety of factors not all related to vascular tone. Dysrhythmias would affect conduction and the function of the heart chambers but not vascular tone. Truncus arteriosus results in only one large artery leaving the heart.

The pathologic changes that occur in the development of coronary atherosclerotic lesions include cell damage resulting from which of the following? (Select all that apply.)

Damage to endothelial cells by oxidized lipids releases inflammatory mediators that form atherosclerotic plaques. A decrease in smooth muscle and a chronic buildup of calcium cells do not contribute to the development of coronary atherosclerotic lesions.

What factor causes a congenital heart disease to produce cyanosis?

Disorders that result in right-to-left shunting cause cyanosis. A left-to-right shunt occurs when oxygenated blood from the left side of the heart or aorta flows back into the right side to be recirculated through the lungs. The blood reaching the systemic circulation is oxygenated and the infant is not cyanotic (acyanotic defect). However, the right side of the heart has an increased workload because of the extra shunt blood. In time, the overload of the right side of the heart can result in right ventricular hypertrophy and high right-sided heart pressures. Large ventricular septal defects may be apparent at birth because of rapidly developing right-sided heart failure and a loud systolic murmur. The majority of atrial septal defects occur at the location of the foramen ovale. The abnormal septal opening may be of variable size. Small defects (1 cm) are well tolerated. Even larger atrial septal defects may be asymptomatic for many years as long as the shunt flow is left to right and therefore acyanotic.

Which condition is an endocrine disorder that causes elevated blood pressure? (Select all that apply.)

Endocrine disorders that result in hypertension include Cushing disease and hyperthyroidism. While Guillain-Barré syndrome results in hypertension, it is neurologic disorder. While coarctation of the aorta causes high blood pressure, it is a cardiac disorder. While pheochromocytoma causes high blood pressure, it is a tumor of adrenal gland tissue.

The nurse includes what information when educating a client concerning a first-degree heart block? (Select all that apply.)

First-degree block is generally identified by a prolonged PR interval (more than 0.20 second) on the ECG. Drugs and organic heart disorders, such as myocardial ischemia and congenital heart defects, may cause first-degree block. First-degree block is generally monitored, but not actively managed except to alleviate the underlying cause, if possible. A second-degree Type II block may also result in severe bradycardia due to the number of dropped beats. First-degree block is a common finding and may occur in the absence of organic heart disease.

In a patient with mitral stenosis, cardiac catheterization findings would indicate increased pressure in the

In mitral valve stenosis, left atrial pressure remains higher than ventricular pressure throughout diastole. Mitral valve stenosis is not characterized by increased pressure in the right ventricle, left ventricle, or right atria.

Early compensation for hypovolemic shock includes

In the early stage of shock, the adrenal medulla is stimulated to release increased amounts of the catecholamines epinephrine and norepinephrine (NE), which circulate to the heart and stimulate β-1 receptors, thus increasing cardiac output. Heart rate initially increases. Systemic vascular resistance is not decreased in early hypovolemic shock. Blood is shunted to the brain in cases of shock.

A patient experiencing an acute myocardial infarction (MI) is given a drug to lyse the clot in the coronary artery. What is the best explanation for the sudden development of a serious arrhythmia once circulation is restored?

Ischemic cells may produce oxygen-free radicals when oxygen supplies are restored. This process has been called reperfusion injury. Reactive oxygen molecules are unstable and will attack membrane structures, denature proteins, and break apart cell DNA. Cardiogenic shock, increased oxygen, and the effects of resuscitation drugs would not account for the arrhythmia.

Which describes a pathologic manifestation of neurogenic shock?

Neurogenic shock results from loss of sympathetic activation of arteriolar smooth muscle. Medullary depression (brain injury, drug overdose) or lesions of sympathetic nerve fibers (spinal cord injury) are the usual causes. Release of vasodilatory mediators such as histamine into the circulation and massive immune system activation are seen in anaphylactic shock. Increased sympathetic nervous stimulation is not a characteristic of neurogenic shock.

What causes vasodilation? (Select all that apply.)

Nitric oxide, histamine, and kinins cause vasodilation. Angiotensin II is one of the most potent vasoconstrictors. The other three choices all cause vasodilation. A vasopressor agent is any medication that tends to raise reduced blood pressure.

A patient with heart failure reports awakening intermittently with shortness of breath. Which terms appropriately describes this clinical manifestation?

Paroxysmal nocturnal dyspnea refers to intermittent attacks of severe dyspnea that occur during the night. Dyspnea is a general term referring to difficulty breathing. Cyanosis is the appearance of a blue or purple coloration of the skin or mucous membranes due to the tissues near the skin surface being low on oxygen. Bradypnea describes abnormal slowness of breathing.

Which condition may result in chronic pulmonary hypertension, right ventricular hypertrophy, and right-sided heart failure?

Pulmonary hypertension, right ventricular hypertrophy, and right-sided heart failure result from untreated mitral valve stenosis. Syncope, fatigue, low systolic blood pressure, and faint pulses are common signs and symptoms of aortic valve stenosis. Aortic insufficiency is characterized by a high-pitched blowing murmur during ventricular diastole. Patients may complain of palpitations and a throbbing or pounding heart because of the large ventricular stroke volume. Common presenting symptoms of acute myocarditis include fatigue, dyspnea on exertion, and dysrhythmia with associated palpitations.

Which term is determined by stroke volume, speed of ejection, and arterial distensibility?

Pulse pressure is determined by stroke volume, speed of ejection of the stroke volume, and arterial distensibility. Arterial pulse pressure is the difference between the systolic and diastolic blood pressure. Mean arterial pressure is the average pressure in the circulating system throughout the cardiac cycle. Diastolic pressure is the pressure excreted during the rest phase of the cardiac cycle.

Which clinical manifestation differentiates myocardial infarction (MI) from angina pectoris? (Select all that apply.)

Radiating chest pain is a clinical finding for individuals experiencing myocardial infarction. Myocardial ischemia and infarction are indicated on the ECG by ST-segment changes. Serum protein marker elevations such as troponin and CK-MB are clinical findings for individuals experiencing myocardial infarction. Exercise induced chest pain is a classic symptom of angina pectoris. Chest pain that is aggravated by coughing is more likely observed with angina pectoris than myocardial infarction.

Which left atrial pressure readings indicates a risk of increased capillary filtration that results in the clinical manifestations of pulmonary edema?

Readings at or above 25 mm Hg are associated with increased capillary filtration and pulmonary edema. The normal left atrial pressure is 4 to 12 mm Hg.

What stimulates the release of renin? (Select all that apply.)

Renal hypoperfusion, sympathetic activation, and decreased sodium delivery stimulate renin release. Increased heart rate and parasympathetic activation do not stimulate the release of renin.

Which type of shock is characterized by generalized vasodilation and peripheral pooling of blood? (Select all that apply.)

Septic shock, neurogenic shock, and anaphylactic shock are characterized by excessive vasodilation and peripheral pooling of blood. Cardiac output is inadequate because of reduced preload. Cardiogenic shock occurs primarily as a result of severe dysfunction of the left or right ventricles, or both, that results in inadequate cardiac pumping. Hypovolemic shock is a result of excessive blood loss; vasoconstriction is initially seen in this form of shock.

A patient has a regular heart rate of 54 beats/min. The nurse would document this rhythm as

Sinus bradycardia is defined as a heart rate of less than 60 beats/min. Normal sinus rhythm is defined as an impulse rate between 60 and 100 per minute. Sinus arrhythmia is a normal finding associated with fluctuations in autonomic influences and respiratory dynamics. Sinus tachycardia is an abnormally fast heart rate of greater than 100 beats/min.

What effect does stimulation of the sympathetic nervous system have on the arterioles and resulting systemic reaction? (Select all that apply.)

Stimulation of the sympathetic nervous system results in increased vascular resistance, increased blood pressure, increased afterload, and constriction of the arterioles. Stimulation of the sympathetic nervous system results in constriction, not dilation, of the arterioles.

Which is a major determinant of diastolic blood pressure?

Systemic vascular resistance is the major determinant of diastolic blood pressure. It reflects the arteriolar radius and the degree of constriction, and it is the main variable in determining afterload. Stroke volume is the primary factor impacting systolic pressure. The end-diastolic volume is determined by the amount of blood returned to the heart between contractions, and is typically called the heart s preload. Heart rate is the number of times the heart contracts within a 60-second time frame

Aortic and carotid baroreceptors are activated by ___________, resulting in ___________.

The aortic and carotid baroreceptors respond to a decrease in blood pressure by stimulating the sympathetic nervous system of the heart and vascular bed, increasing heart rate, cardiac output, and systemic vascular resistance. They also inhibit the parasympathetic nervous system's influence on the heart, which results in an increased heart rate. Aortic and carotid baroreceptors are activated by a decrease in blood pressure, but the results are not the normalization of blood pressure, but rather an increase in cardiac output (CO), systemic vascular resistance (SVR), heart rate (HR), and blood pressure.

The vasoactive mediators released in septic shock contribute to increase

The kinin system is activated and bradykinin is released, which results in vasodilation and increased capillary permeability. Histamine also increases capillary permeability, which enhances edema formation. Systemic vascular resistance is decreased in septic shock. The complement system is activated with release of C5a and C3a, which can produce microemboli and endothelial cell destruction. The coagulation system is activated and may enhance the development of microemboli. Histamine, a potent vasodilator, is released by mast cells.

A common cause of heart failure is which of the following? (Select all that apply.)

The most common cause of HF is myocardial ischemia from coronary artery disease, followed by hypertension and dilated cardiomyopathy. Valvular heart disease and anemia are not common causes of heart failure.

Which medication classification is used to decrease preload in patients with heart failure?

The right ventricle is particularly sensitive to reductions in preload, and care must be taken to avoid a significant drop in right ventricular output when intravascular volume is decreased. Drugs, such as diuretics may be administered to reduce intravascular volume. Diuretics promote the excretion of fluid by increasing renal blood flow and blocking sodium and chloride reabsorption, or both. Calcium channel blockers are not commonly used to decrease cardiac preload. Corticosteroids are not used for affecting cardiac preload. β-blockers slow the heart rate and reduces the force with which the heart muscle contracts, thereby lowering blood pressure.

For the patient in hypovolemic shock, what compensatory mechanism will help preserve adequate circulation?

The sympathetic nervous system stimulates cells in the kidney to release renin, which triggers the renin-angiotensin-aldosterone cascade. The sympathetic not the parasympathetic nervous system is involved in the compensatory mechanisms of hypovolemic shock. Antidiuretic hormone (ADH, vasopressin), is secreted from the posterior pituitary gland in response to reduced blood volume. ADH stimulates the kidney tubules to reabsorb water and improves the vascular response to catecholamines. Renin triggers the formation of angiotensin II, which is a potent vasoconstrictor, and also stimulates the kidney nephrons to conserve sodium and water.

Systemic blood pressure is determined by which factor(s)? (Select all that apply.)

The systemic arterial blood pressure is the physiologic result of the cardiac output (CO) and the resistance to the ejection (SVR) of blood from the heart. Cardiac output is the product of two variables: stroke volume (SV) and heart rate (HR) (CO = SV × HR). SV is the specific volume of blood leaving the heart with each contraction. Pulmonary vascular resistance (PVR) is not a factor in determining systemic blood pressure.

Systemic vascular resistance (SVR) can be indirectly estimated with the use of which blood pressure measurement?

The systemic diastolic pressure is determined by the narrowing of blood vessel diameter and therefore the resistance to blood flow, whether from peripheral vascular constriction or atherosclerosis. Systolic pressure is not as influenced by the narrowing of blood vessel diameter. Pulmonary arterial pressure is generated by the right ventricle ejecting blood into the pulmonary artery. By definition, the volume of blood within a ventricle immediately before a contraction is known as the end-diastolic volume.

The renin-angiotensin system (RAS) alters blood pressure in response to

When blood flow is restricted to the kidney by low blood volume, low cardiac output, or stricture of the renal artery, the kidney secretes more renin into the bloodstream, which in turn changes angiotensinogen to angiotensin I. Angiotensin-converting enzyme (ACE) then changes angiotensin I to a potent vasoconstrictor, angiotensin II. Angiotensin II then increases vascular constriction, systemic vascular resistance, and blood pressure. The renin-angiotensin system (RAS) is not associated with the brain, liver, or lungs.

The shift to anaerobic metabolism in shock results in

When the citric acid cycle is inhibited, pyruvate accumulates in the cytoplasm. Pyruvate accumulation would quickly inhibit further glycolysis and shut down ATP production entirely except that it can be converted to a substance called lactate, which diffuses from the cell and into the extracellular fluid. A shift to anaerobic metabolism in shock does not result in metabolic alkalosis, decreased oxygen utilization, or decreased hydrogen ion production.

Which receptor is responsible for innervation of the arterioles?

α-1 receptors are responsive to stimulation by the autonomic nervous system. Stimulation of the α-1 receptor causes vasoconstriction and increased systemic vascular resistance. Renin release is increased when neurotransmitters released by the sympathetic nervous system bind to β1 receptors in the kidney. β-adrenergic agonists, also known as β2-adrenergic receptor agonists, are a class of drugs used to treat asthma and other pulmonary disease states. α2-adrenergic receptors mediate part of the diverse biological effects of the endogenous catecholamines epinephrine and norepinephrine