Current Heart

Venous Hum

A venous hum is usually heard after age 2 years. It is located in the infraclavicular area on the right. It is a continuous musical hum of grade I-III intensity and may be accentuated in diastole and with inspiration. It is best heard in the sitting position. Turning the child's neck, placing the child supine, and compressing the jugular vein obliterates the venous hum. Venous hum is caused by turbulence at the confluence of the subclavian and jugular veins.

Ventricular Septal Defect Treatment

A. MEDICAL MANAGEMENT Patients who develop symptoms can be managed with anticongestive treatment, particularly diuretics and systemic afterload reduction, prior to surgery or if it is expected that the defect will close over time. B. SURGICAL TREATMENT Patients with cardiomegaly, poor growth, poor exercise tolerance, or other clinical abnormalities who have a significant shunt (> 2:1) typically undergo surgical repair at age 3-6 months. A synthetic or pericardial patch is used for primary closure. In most centers, these children have surgery before age 1 year. As a result, Eisenmenger syndrome has been virtually eliminated. The surgical mortality rate for VSD closure is below 2%. Transcatheter closure of muscular VSDs is also a possibility. Perimembranous VSDs have also been closed in children during catheterization, but a high incidence of complete heart block after placement of the occluding device has slowed the acceptance of this approach.

Atrial Septal Defect Clinical Findings

A. SYMPTOMS AND SIGNS Most infants and children with an ASD have no cardiovascular symptoms. Older children and adults can present with exercise intolerance, easy fatigability, or, rarely, heart failure. The direction of flow across the ASD is determined by the compliance of the ventricles. Because the right ventricle is normally more compliant, shunting across the ASD is left-to-right as blood follows the path of least resistance. Therefore, cyanosis does not occur unless RV dysfunction occurs, usually as a result of pulmonary hypertension, leading to reversal of the shunt across the defect. Peripheral pulses are normal and equal. The heart is usually hyperactive, with an RV heave felt best at the mid to lower left sternal border. S2 at the pulmonary area is widely split and often fixed. In the absence of associated pulmonary hypertension, the pulmonary component is normal in intensity. A grade I-III/VI ejection-type systolic murmur is heard best at the left sternal border in the second intercostal space. This murmur is caused by increased flow across the pulmonic valve, not flow across the ASD. A mid-diastolic murmur is often heard in the fourth intercostal space at the left sternal border. This murmur is caused by increased flow across the tricuspid valve during diastole. The presence of this murmur suggests high flow with a pulmonary-to-systemic blood flow ratio greater than 2:1.

Atrial Septal Defect General Considerations

Atrial septal defect (ASD) is an opening in the atrial septum permitting the shunting of blood between the atria. There are three major types: ostium secundum, ostium primum, and sinus venosus. Ostium secundum is the most common type and represents an embryologic deficiency in the septum secundum or too large of a central hole in the septum primum. Ostium primum defect is associated with atrioventricular septal defects. The sinus venosus defect is frequently associated with abnormal pulmonary venous return, as the location of the sinus venosus is intimately related to the right upper pulmonary vein. Ostium secundum ASD occurs in 10% of patients with congenital heart disease and is two times more common in females than in males. The defect is most often sporadic but may be familial or have a genetic basis (Holt-Oram syndrome). After the third decade, atrial arrhythmias or pulmonary vascular disease may develop. Irreversible pulmonary hypertension resulting in cyanosis as atrial level shunting becomes right-to-left and ultimately right heart failure can occur and is a life-limiting process (Eisenmenger syndrome).

INSPECTION AND PALPATION

Chest conformation should be noted in the supine position. A precordial bulge indicates cardiomegaly. Palpation may reveal increased precordial activity, right ventricular lift, or left-sided heave; a diffuse point of maximal impulse; or a precordial thrill caused by a grade IV/VI or greater murmur. The thrill of aortic stenosis is found in the suprasternal notch. In patients with severe pulmonary hypertension, a palpable pulmonary closure (P2) is frequently noted at the upper left sternal border.

Patent Ductus Arteriosus

Clinical Findings A. SYMPTOMS AND SIGNS The clinical findings and course depend on the size of the shunt and the degree of pulmonary hypertension. 1. Moderate to large patent ductus arteriosus—Pulses are bounding, and pulse pressure is widened due to diastolic runoff through the ductus. S1 is normal and S2 is usually narrowly split. In large shunts, S2 may have a paradoxical split (eg, S2 narrows on inspiration and widens on expiration). Paradoxical splitting is caused by volume overload of the LV and prolonged ejection of blood from this chamber. The murmur is characteristic. It is a rough machinery murmur maximal at the second left intercostal space. It begins shortly after S1, rises to a peak at S2, and passes through the S2 into diastole, where it becomes a decrescendo murmur and fades before the S1. The murmur tends to radiate well to the anterior lung fields but relatively poorly to the posterior lung fields. A diastolic flow murmur is often heard at the apex. 2. Patent ductus arteriosus with increased pulmonary vascular resistance—Flow across the ductus is diminished. S2 is single and accentuated, and no significant heart murmur is present. The pulses are normal rather than bounding.

Atrioventricular Septal Defect

Clinical Findings A. SYMPTOMS AND SIGNS The partial form may produce symptoms similar to ostium secundum ASD. Patients with complete AVSD usually have symptoms such as failure to thrive, tachypnea, diaphoresis with feeding, or recurrent bouts of pneumonia. In the neonate with the complete form, the murmur may be inaudible due to relatively equal systemic and pulmonary vascular resistance (PVR). After 4-6 weeks, as PVR drops, a nonspecific systolic murmur develops. The murmur is usually not as harsh as that of an isolated VSD. There is both right- and left-sided cardiac enlargement. S2 is loud, and a pronounced diastolic flow murmur may be heard at the apex and the lower left sternal border. If severe pulmonary vascular obstructive disease is present, there is usually dominant RV enlargement. S2 is palpable at the pulmonary area and no thrill is felt. A nonspecific short systolic murmur is heard at the lower left sternal border. No diastolic flow murmurs are heard. If a right-to-left shunt is present, cyanosis will be evident.

Coarctation of the Aorta

ESSENTIALS OF DIAGNOSIS & TYPICAL FEATURES Absent or diminished femoral pulses. Upper to lower extremity systolic blood pressure gradient of > 20 mm Hg. Blowing systolic murmur in the back or left axilla.

Patent Ductus Arteriosus

ESSENTIALS OF DIAGNOSIS & TYPICAL FEATURES Continuous machinery type murmur. Bounding peripheral pulses if large ductus present. Presentation and course depends on size of the ductus and the pulmonary vascular resistance. Clinical features of a large ductus are failure to thrive, tachypnea, and diaphoresis with feeds. Left-to-right shunt with normal pulmonary vascular resistance.

Atrial Septal Defect

ESSENTIALS OF DIAGNOSIS & TYPICAL FEATURES Fixed, widely split S2, RV heave. Grade I-III/VI systolic ejection murmur at the pulmonary area. Large shunts cause a diastolic flow murmur at the lower left sternal border (increased flow across the tricuspid valve). ECG shows rsR′ in lead V1. Frequently asymptomatic.

Aortic Stenosis

ESSENTIALS OF DIAGNOSIS & TYPICAL FEATURES Harsh systolic ejection murmur at the upper right sternal border with radiation to the neck. Thrill in the carotid arteries. Systolic click at the apex. Dilation of the ascending aorta on chest radiograph.

Ventricular Septal Defect

ESSENTIALS OF DIAGNOSIS & TYPICAL FEATURES Holosystolic murmur at lower left sternal border with RV heave. Presentation and course depend on size of defect and the pulmonary vascular resistance. Clinical features are failure to thrive, tachypnea, and diaphoresis with feeds. Left-to-right shunt with normal pulmonary vascular resistance. Large defects may cause Eisenmenger syndrome if not repaired early.

Atrioventricular Septal Defect

ESSENTIALS OF DIAGNOSIS & TYPICAL FEATURES Murmur often inaudible in neonates. Loud pulmonary component of S2. Common in infants with Down syndrome. ECG with extreme left axis deviation.

Pulmonary Valve Stenosis

ESSENTIALS OF DIAGNOSIS & TYPICAL FEATURES No symptoms in mild or moderate stenosis. Cyanosis and a high incidence of right-sided HF in ductal-dependent lesions. RV lift with systolic ejection click heard at the third left intercostal space. S2 widely split with soft to inaudible P2; grade I-VI/VI systolic ejection murmur, maximal at the pulmonary area. Dilated pulmonary artery on chest radiograph.

Atrioventricular Septal Defect

General Considerations Atrioventricular septal defect (AVSD) results from incomplete fusion of the embryonic endocardial cushions. The endocardial cushions help to form the "crux" of the heart, which includes the lower portion of the atrial septum, the membranous portion of the ventricular septum, and the septal leaflets of the tricuspid and mitral valves. AVSD accounts for about 4% of all congenital heart disease. Sixty percent of children with Down syndrome have congenital heart disease, and of these, 35%-40% have an AVSD. AVSDs are defined as partial or complete. The physiology of the defect is determined by the location of the AV valves. If the valves are located in the midportion of the defect (complete AVSD), both atrial and ventricular components of the septal defect are present and the left- and right-sided AV valves share a common ring or orifice. In the partial form, there is a low insertion of the AV valves, resulting in a primum ASD without a ventricular defect component. In partial AVSD, there are two separate AV valve orifices and usually a cleft in the left-sided valve. Partial AVSD behaves like an isolated ASD with variable amounts of regurgitation through the cleft in the left AV valve. The complete form causes large left-to-right shunts at both the ventricular and atrial levels with variable degrees of AV valve regurgitation. If there is increased pulmonary vascular resistance, the shunts may be bidirectional. Bidirectional shunting is more common in Down syndrome or in older children who have not undergone repair.

Patent Ductus Arteriosus

General Considerations PDA is the persistence of the normal fetal vessel joining the pulmonary artery to the aorta. It closes spontaneously in normal-term infants at 1-5 days of age. PDA accounts for 10% of all congenital heart disease. The incidence of PDA is higher in infants born at altitudes over 10,000 ft. It is twice as common in females as in males. The frequency of PDA in preterm infants weighing less than 1500 g ranges from 20% to 60%. The defect may occur as an isolated abnormality or with associated lesions, commonly coarctation of the aorta and VSD. Patency of the ductus arteriosus may be necessary in some patients with complex forms of congenital heart disease (eg, hypoplastic left heart syndrome [HLHS], pulmonary atresia). Prostaglandin E2 (PGE2) is a product of arachidonic acid metabolism and continuous intravenous infusion maintains ductal patency.

Intensity

Grade I describes a soft murmur heard with difficulty; grade II, soft but easily heard; grade III, loud but without a thrill; grade IV, loud and associated with a precordial thrill; grade V, loud, with a thrill, and audible with the edge of the stethoscope; grade VI, very loud and audible with the stethoscope off the chest.

Ventricular Septal Defect

Patients with small or moderate left-to-right shunts usually have no cardiovascular symptoms. Patients with large left-to-right shunts are usually ill early in infancy. These infants have frequent respiratory infections and gain weight slowly. Dyspnea, diaphoresis, and fatigue are common. These symptoms can develop as early as 1-6 months of age. Older children may experience exercise intolerance. Over time, in children and adolescents with persistent large left-to-right shunt, the pulmonary vascular bed undergoes structural changes, leading to increased pulmonary vascular resistance and reversal of the shunt from left-to-right to right-to-left (Eisenmenger syndrome). Cyanosis will then be present. 1. Small left-to-right shunt—No lifts, heaves, or thrills are present. The first sound at the apex is normal, and the second sound at the pulmonary area is split physiologically. A grade II-IV/VI, medium- to high-pitched, harsh pansystolic murmur is heard best at the left sternal border in the third and fourth intercostal spaces. The murmur radiates over the entire precordium. No diastolic murmurs are heard. 2. Moderate left-to-right shunt—Slight prominence of the precordium with moderate LV heave is evident. A systolic thrill may be palpable at the lower left sternal border between the third and fourth intercostal spaces. The second sound at the pulmonary area is most often split but may be single. A grade III-IV/VI, harsh pansystolic murmur is heard best at the lower left sternal border in the fourth intercostal space. A mitral diastolic flow murmur indicates that pulmonary blood flow and subsequently the pulmonary venous return are significantly increased by the large shunt. 3. Large ventricular septal defects with pulmonary hypertension—The precordium is prominent, and the sternum bulges. Both LV and RV heaves are palpable. S2 is palpable in the pulmonary area. A thrill may be present at the lower left sternal border. S2 is usually single or narrowly split, with accentuation of the pulmonary component. The murmur ranges from grade I to IV/VI and is usually harsh and pansystolic. Occasionally, when the defect is large or ventricular pressures approach equivalency, a murmur is difficult to hear. A diastolic flow murmur may be heard, depending on the size of the shunt.

ASD Treatment

Surgical or catheterization closure is generally recommended for symptomatic children with a large atrial level defect and associated right heart dilation. In the asymptomatic child with a large hemodynamically significant defect, closure is performed electively at age 1-3 years. Most defects are amenable to nonoperative device closure during cardiac catheterization, but the defect must have adequate tissue rims on all sides on which to anchor the device. The mortality for surgical closure is less than 1%. When closure is performed by age 3 years, late complications of RV dysfunction and dysrhythmias are avoided.

Heart Sounds

The first heart sound (S1) is the sound of atrioventricular (AV) valve closure. It is best heard at the lower left sternal border and is usually medium-pitched. Although S1 has multiple components, only one of these (M1—closure of the mitral valve) is usually audible. The second heart sound (S2) is the sound of semilunar valve closure. It is best heard at the upper left sternal border. S2 has two component sounds, A2 and P2 (aortic and pulmonic valve closure). Splitting of S2 varies with respiration, widening with inspiration and narrowing with expiration. Abnormal splitting of S2 may be an indication of cardiac disease (Table 20-3). A prominent or loud P2 is associated with pulmonary hypertension.The third heart sound (S3) is the sound of rapid left ventricular filling. It occurs in early diastole, after S2, and is medium- to low-pitched. In healthy children, S3 diminishes or disappears when going from supine to sitting or standing. A pathologic S3 is often heard in the presence of poor cardiac function or a large left-to-right shunt. The fourth heart sound (S4) is associated with atrial contraction and increased atrial pressure and has a low pitch similar to that of S3. It occurs just prior to S1 and is not normally audible. It is heard in the presence of atrial contraction into a noncompliant ventricle as in hypertrophic or restrictive cardiomyopathy or from other causes of diastolic dysfunction. Ejection clicks are usually related to dilate great vessels or valve abnormalities. They are heard during ventricular systole and are classified as early, mid, or late. Early ejection clicks at the mid left sternal border are from the pulmonic valve. Aortic clicks are typically best heard at the apex. In contrast to aortic clicks, pulmonic clicks vary with respiration, becoming louder during inspiration. A mid to late ejection click at the apex is most typically caused by mitral valve prolapse.

Still Murmur

This is the most common innocent murmur of early childhood. It is typically heard between 2 and 7 years of age. It is the loudest midway between the apex and the lower left sternal border. Still murmur is a musical or vibratory, short, high-pitched, grade I-III early systolic murmur. It is loudest when the patient is supine. It diminishes or disappears with inspiration or when the patient is sitting. The Still murmur is louder in patients with fever, anemia, or sinus tachycardia from any reason.

Atrioventricular Septal Defect

Treatment Spontaneous closure of this type of defect does not occur and therefore surgery is required. In the partial form, surgery carries a low mortality rate (1%-2%), but patients require follow-up because of late-occurring LV outflow tract obstruction and mitral valve dysfunction. The complete form carries a higher mortality rate. Complete correction in the first year of life, prior to the onset of irreversible pulmonary hypertension, is obligatory.

Patent Ductus Arteriosus

Treatment Surgical closure is indicated when the PDA is large and the patient is small. Caution must be given to closing a PDA in patients with pulmonary vascular obstructive disease and right-to-left shunting across the ductus as this could result in RV failure. Patients with large left-to-right shunts require repair by age 1 year to prevent the development of progressive pulmonary vascular obstructive disease. Symptomatic PDA with normal pulmonary artery pressure can be safely coil or device-occluded in the catheterization laboratory, ideally after the child has reached 5 kg. Patients with nonreactive pulmonary vascular obstruction, pulmonary vascular resistance greater than 10 Wood units (normal, < 3), and a ratio of pulmonary to systemic resistance greater than 0.7 (normal, < 0.3) despite vasodilator therapy (eg, nitric oxide) should not undergo PDA closure. These patients are made worse by PDA closure because the flow through the ductus allows preserved RV function and maintains cardiac output to the systemic circulation. These patients can be managed with pulmonary vasodilator therapy, but eventually may require heart-lung transplant in severe cases. Presence of a symptomatic PDA is common in preterm infants. Indomethacin, a prostaglandin synthesis inhibitor, is often used to close the PDA in premature infants. Indomethacin does not close the PDA of full-term infants or children. The success of indomethacin therapy is as high as 80%-90% in premature infants with a birth weight greater than 1200 g, but it is less successful in smaller infants. Indomethacin (0.1-0.3 mg/kg orally every 8-24 hours or 0.1-0.3 mg/kg parenterally every 12 hours) can be used if there is adequate renal, hematologic, and hepatic function. Because indomethacin may impair renal function, urine output, BUN, and creatinine should be monitored during therapy. If indomethacin is not effective and the ductus remains hemodynamically significant, surgical ligation should be performed. If the ductus partially closes so that the shunt is no longer hemodynamically significant, a second course of indomethacin may be tried.

Ventricular Septal Defect General Considerations

Ventricular septal defect (VSD) is the most common congenital heart malformation, accounting for about 30% of all congenital heart disease. Defects in the ventricular septum occur both in the membranous portion of the septum (most common) and the muscular portion. VSDs follow one of four courses: A. SMALL, HEMODYNAMICALLY INSIGNIFICANT VENTRICULAR SEPTAL DEFECTS Between 80% and 85% of VSDs are small (< 3 mm in diameter) at birth and will close spontaneously. In general, small defects in the muscular interventricular septum will close sooner than those in the membranous septum. In most cases, a small VSD never requires surgical closure. Fifty percent of small VSDs will close by age 2 years, and 90% by age 6 years, with most of the remaining closing during the school years. B. MODERATE-SIZED VENTRICULAR SEPTAL DEFECTS Asymptomatic patients with moderate-sized VSDs (3-5 mm in diameter) account for 3%-5% of children with VSDs. In general, these children do not have clear indicators for surgical closure. Historically, in those who had cardiac catheterization, the ratio of pulmonary to systemic blood flow is usually less than 2:1, and serial cardiac catheterizations demonstrate that the shunts get progressively smaller. If the patient is asymptomatic and without evidence of pulmonary hypertension, these defects can be followed serially as some close spontaneously over time. C. LARGE VENTRICULAR SEPTAL DEFECTS WITH NORMAL PULMONARY VASCULAR RESISTANCE These defects are usually 6-10 mm in diameter. Unless they become markedly smaller within a few months after birth, they often require surgery. The timing of surgery depends on the clinical situation. Many infants with large VSDs and normal pulmonary vascular resistance develop symptoms of failure to thrive, tachypnea, diaphoresis with feeds by age 3-6 months, and require correction at that time. Surgery before age 2 years in patients with large VSDs essentially eliminates the risk of pulmonary vascular disease. D. LARGE VENTRICULAR SEPTAL DEFECTS WITH PULMONARY VASCULAR OBSTRUCTIVE DISEASE The direction of flow across a VSD is determined by the resistance in the systemic and pulmonary vasculature, explaining why flow is usually left-to-right. In large VSDs, ventricular pressures are equalized, resulting in increased pulmonary artery pressure. In addition, shear stress caused by increased volume in the pulmonary circuit causes increased resistance over time. The vast majority of patients with inoperable pulmonary hypertension develop the condition progressively. The combined data of the multicenter National History Study indicate that almost all cases of irreversible pulmonary hypertension can be prevented by surgical repair of a large VSD before age 2 years.