TBL: Heart failure in infants and children

Result of increased LA pressure and decreased RA pressure

Anatomical closure of foramen ovale (FO) by septum secundum -Permanent closure may not occur=25% have probe patent FO

Treatment for CHF in infancy

General objectives: -Reducing preload with diuretics -Enhancing cardiac contractility -Reducing afterload -Enhancing nutrition

Symptoms of TOF

Harsh systolic ejection murmur at left upper sternal border with radiation to both lung fields Non-existent to severe cyanosis (depends on degree of pulmonic obstruction and right to left shunting) History of squatting (increases arterial pressure in aorta=decreases right to left shunting), hyperpnea, irritability, and cyanosis "Boot shaped" heart on x-ray

Measuring cyanosis

Noninvasive pulse oximetry Normal for full term=95-100% (may be 92-96%) Normal for pre-term=84-90% 24 hr value less than 95%=possibility of cyanotic defect should be investigated

In Eisenmenger's syndrome, if the cardiac defect is easily repairable, a __________ may be done, but if there is significant heart failure associated with it, a ________ is the only option

Single or dual lung transplant Heart lung transplant

Four main types of ASDs

1. Secundum=>80%, located in fossa ovalis region -87% close by age 4, can be closed using transcatheter device 2. Ostium primum=second most common, associated with cleft mitral valve and AV canal -Do not close on own 3&4. Coronary Sinus and Sinus venosus=rare

Closure of umbilical arteries (UA) is primarily due to

1. Trauma to vessels 2. Increased circulating norepinephrine and epinephrine associated with stress of birthing 3. Change in O2 tension (insignificant hemorrhage if umbilical cord not tied) Results=increased resistance and increased blood pressure (afterload)

Decreased resistance in pulmonary circulation

1/10th of that before birth -Still elevated for days after birth=some congenital defect murmurs not heard for several days

Spontaneous closure occurs in ______ percent of VSDs, the majority of which are __________

30 to 40 percent Muscular

Incidence of congenital heart disease

8.1 per 1000 live births -30 to 60 percent detected prenatally with echocardiography Higher risk in infants with abnormal karyotypes-Down syndrome, Turner syndrome

Results of decreased pulmonary pressure and increased aortic pressure

Causes reversal of flow in ductus arteriosus=constriction and eventual closure

Transposition of the Great Vessels (TGV)

Aorta and pulmonary artery malpositioned=aorta arises from right ventricle and pulmonary artery arises from left ventricle

Cardiac causes of increased cardiac demand or impaired cardiac function leading to CHF

Arrythmias (tachycardia or bradycardia) Structural heart disease Myocardial dysfunction (systolic or diastolic)

At birth, breathing is stimulated by

Asphyxia due to closure of the placental circulation and cooling of the body -Causes increase in circulating catecholamines from sympathetic nerves and adrenal medulla=increase in arterial pressure=increase in left atrial pressure

Differental diagnosis of neonatal cyanosis

CNS depression RIght to left shunt because of congenital heart disease V/Q mismatch (primary lung disease and polycythemia) Congestive heart failure with alveolar hypoventilation Mechanical impingement on lung function (diaphragmatic hernia, pneumothorax, vascular ring, etc.) Persistence of fetal circulation (TGA, TOF, TA, TAPVR, hypoplastic left heart, tricuspid atrasia) Methemoglobinemia Shock and sepsis Neuromuscular conditions (ex. Werdnig-Hoffman disease) Respiratory depression from maternal medications (meperidine, magnesium sulfate) *Differentiate by spontaneous movement, respiratory pattern, presence of heart murmur, blood gases and response to 100% O2, blood studies, and chest x-ray* *Cyanosis in congenital heart defect=O2 administration won't alter deficiency* *Cyanosis in respiratory problems=O2 admin. should increase O2 saturation*

Congestive heart failure in infancy (CGF)

Cardiac output inadequate for metabolic demands of patient -History important: clues during feeding=infant with CHF may take 30-45 min to feed (normal 10-20 min) with increased respiratory effort, fatigue, and sweating, caloric intake of <75 cal/kg/day not uncommon=slow weight gain; frequent lower respiratory tract infections

Surgical repair of VSD is indicated if

Child experiences CHF, failure to thrive, left to right shunt > 2:1, or pulmonary hypertension (want to repair before pulmonary hypertension)

Lesions which depend on flow via ductus arteriosus to maintain systemic circulation

Coarctation of the aorta Critical aortic stenosis Hypoplastic left heart syndrome

Lesions most commonly not diagnosed prior to discharge

Coarctation of the aorta Interrupted aortic arch Critical aortic stenosis Hypoplastic left heart syndrome Transposition of the great vessels Truncus arteriosus Tetralogy of Fallow Total anomalous pulmonary venous connection

Women at risk for having child with congenital heart disease

Diabetic Positive family history Exposure to drugs: Lithium or indomethacin First trimester rubella High altitude

Most common ways for child to present with congenital heart disease

Cyanosis Heart murmur Congestive heart failure

Decreased pulmonary pressure is due to

Decreased pulmonary resistance -Thus decreases right ventricular pressure=decreases right atrial pressure

Increased left atrial pressure is due to

Decreased pulmonary resistance=increased flow to left atrium Reduction of flow to right atrium due to closure of umbilical vein=decrease in right atrial pressure Increased afterload for left ventricle due to closure of umbilical aa. and increased NE and Epi

Preload reducing agents

Diuretics Ex. furosemide, hydrochlorothiazide and spironolactone

Protaglandin E1 (PGE1)

Drug given to keep PDA open Indications: -Right heart outflow obstruction (pulmonary atresia/stenosis, tricuspid atresia), left outflow obstruction (hypoplastic left heart syndrom, preductal coarctation of the aorta, interrupted aortic arch) and TGV Contraindications: -Hyaline membrane disease, persistent fetal circulation, or left-to-right shunt where PDA would increase already overloaded pulmonary circulation Side effects: -Apnea, systemic hypotension, inhibition of platelet aggregation

Inotropic agents

Enhance contractility Ex. Digoxin, dobutamine, low dose epinephrine, milrinone, dopamine

Differential diagnosis of CHF in infancy

Etiology related to age Neonate: -heart muscle dysfunction (asphyxia, sepsis hypoglycemia) -Structural lesions (tricuspid/pulmonary regurgitation, systemic AV fistual) -HR problems (supraventricular tachycardia, congenital heart block) -Hematologic conditions (anemia, hyperviscosity syndrome) Newborn nursery: -Structural lesions (patent ductus arteriosus, hypoplastic left heart, aortic/pulmonic stenosis) -Heart muscle dysfunction (same as neonate) -Pulmonary, renal, and endocrine problems Early infancy (1-6 weeks): -Structural lesions (coarctation of the aorta, shunts like VSD, AV canal, ASD, and PDA) -Heart muscle dysfunction (endocardial fibroelastosis, Pompe's disease, myocarditis) -Renal and endocrine problems Late infancy -Same as early

Closure of ductus arteriosus in ductal-dependent lesion

Failure of blood to flow between pulmonary and systemic circulation Rapid deterioration of infant=severe metabolic acidosis, seizure, cardiogenic shock, cardiac arrest, end-organ injury -Admin. of O2 closis ductus=contraindicated in cyanosis with ductal dependent lesion -Give PGE1 to help keep ductus open

Increased aortic pressure due to

Increases in NE and decreased TPR

If PDA is present in CHF ______ should be used to close the shunt If coarctation is present in CHF, _____ should be used

Indomethacin PGE1

Ductal-dependent lesions

Infant may not be symptomatic during birth hospitalization

Closure of ductus venosus caused by

No flow after UV is gone

A child with VSD presents with

Murmur, with or without signs and symptoms of congestive heart failure -Murmur=harsh and holosystolic, at mid to lower sternal border -Size of defect=severity of congestive heart failure -Diastolic flow rumble if left to right shunting=functional mitral stenosis

If heart disease is suspected as primary etiology of cyanosis, the next step is

Obtain an echocardiogram

Mustard procedure

Old atrial switch repair for TGV No longer done-congestive heart failure later in life -Arrhythmias and baffle obstruction

Four types of VSD

Perimembranous Muscular Inlet Juxtarterial/supracristal

Actual causes for closure of ductus arteriosus

Pressure gradient reversal=reversal of flow O2=vasoconstrictor, increasing it in DA helps close Loss of prostaglandin E2 (PGE2, vasodilator) from placenta=PGE2 keeps DA open (DA more sensitive to PGE2 than peripheral circulation=little effect on peripheral resistance) Increased clearance of PGE2 by pulmonary circulation Closure assisted with prostaglandin inhibitors (ex. indomethacin), but with ductal dependent lesion, keep DA open with PGE1 Eventually=hypertrophy of left ventricle and reduction in size of right ventricular wall

Noncardiac causes of congestive heart failure

Processes that increase preload (volume overload) Increase afterload (hypertension) Reduce O2 carrying capacity of blood (anemia) Increase demand (sepsis Ex. Renal failure-> congestive heart failure due to fluid retention and anemia

Lesions which depend on flow via ductus arteriosus to maintain pulmonary circulation

Pulmonary atresia Critical pulmonary stenosis Tricuspid atresia Tetralogy of Fallot

Initially Eisenmenger's syndrome is responsive to ________ but once ___________, surgical treatment is the only option

Pulmonary vasodilators (Bosentan, Epoprostenol, Sildenafil) Once pulmonary vasculature is no longer responsive to vasodilators, including O2

Afterload reducing agents

Reduce BP Captopril, Enalapril, Lorsatan, Nitroprusside, Nitroglycerine

Beta blockers

Reverse long term effects of increased sympathetic activity Ex. carvedilol

Four components of TOF

Right outflow tract obstruction Overriding aorta VSD Hypertrophied right ventricle

Closure of umbilical vein

Same as for arteries

Atrial septal defects (ASD)

Second most common type of lesion Usually asymptomatic until adulthood=present with exercise intolerance -Fixed split second heart sound -Increased right to left shunting=diastolic flow rumble across tricuspid valve and/or pulmonic systolic murmur heard

Symptoms of TGV

Single second heart sound from aorta (positioned anteriorly) "Egg on a string" appearance of heart on X-ray Cyanotic at birth Secondary lesion-ASD or patent ductus arteriosus-required for mixing between two separate circulations -W/o secondary lesion would be fatal -"Ductal Dependent" -Ductus kept open with Prostaglandin E1 infusion -Palliative balloon atrial septostomy until surgical arterial switch can be done

Most common congenital heart disease beyond infancy

Tetralogy of Fallot

Most common cyanotic lesions

Tetralogy of Fallot (TOF) Transposition of the great vessels (TGV) -cyanosis=blue/purple coloration of lips, finger tips, mucous membranes -Absolute level of reduced hemoglobin in capillary bed >3g/dL

Most common type of VSD

Textbooks=perimembranous Muscular=likely most common but close more frequently so may never be detected clinically

Lesions where systemic and pulmonary circulations are separated

Transposition of the great vessels

First inspiration

Tremendous negative pressure causes significant compliance changes in lung tissue -Decreased pulmonary vascular resistance=increased venous return to LA and increased LA pressure=decreased RA pressure -Facilitates closure of Foramen Ovale

Eisenmenger's syndrome

Triad of: 1. Systemic-to-pulmonary cardiovascular communication 2. Pulmonary arterial disease 3. Cyanosis Implies that development of pulmonary arterial disease is consequence of increased pulmonary blood flow over prolonged time -Increased pulmonary resistance=reversal of flow through cardiac shut=signs of systemic cyanosis Severe congenital heart defects=increased pulmonary blood flow -VSD (33%), ASD (30%), and PDA (14%) -general progression to Eisenmenger's=prolonged increase in blood flow to pulmonary vasculature with physical changes in pulmonary arterioles -Over time=hypertrophy/hyperplasia of the media=decreased vascular lumen=increased pulmonary vascular resistance=increased pulmonary artery pressure and pulmonary hypertension=Pulmonary arteriolar hypertension (PAH) -When pulmonary artery pressure>left heart pressure=reversal of blood flow into left heart instead of pulmonary circulation -Right to left shunting=cyanosis

AV canal

Two categories: Partial and complete Partial=primum atrial septal defect and cleft mitral valve Complete=primum ASD, common AV canal, and inlet-type VSD Hemodynamic problems: -Interatrial shunting -Interventricular shunting -AV valve function *common in infants with trisomy 21

Most common congenital heart defect is

Ventricular septal defect (VSD)

Acyanotic lesions include

Ventricular septal defect (VSD) Atrial septal defect (ASD) Pulmonary stenosis Patent ductus arteriosus Aortic stenosis Coarctation of the aorta Atrioventricular canal

Physical exam findings of infant with CHF

Weight affected before length Pulse normal or decreased Tachycardia at rest Increased respiratory rate Extremities cool to touch with delayed capillary filling Hepatomegaly in right heart failure Facial edema common, peripheral edema rare unless advanced CHF S3 may be present Pulmonary symptoms rare; Rales=severe CHF or pneumonia Cardiomegaly on x-ray (cardiothoracic ratio >0.55) If large left-to right shunt=increased pulmonary blood flow -Hyperexpansion of lungs, flattened diaphragm Echocardiogram helpful to quatify chamber enlargement/hypertrophy and left ventricular shortening fraction

Inlet VSD

doesn't close spontaneously=must have surgery associated with AV canal and Down syndrome

Supracristal VSD

doesn't close spontaneously=must have surgery most often seen in Asian populations