Varying degrees of cyanosis depend on the amount of pulmonary blood flow. If not diagnosed at birth, the infantmay develop signs of heart failure as pulmonary vascularresistance decreases. The signs then include tachypnea andcough. Peripheral pulses are usually bounding as a result ofthe diastolic runoff into the pulmonary arteries. A single S2 is due to the single valve. There may be a systolic ejection click, and there is often a systolic murmur at the left sternal border.
ECG findings include combined ventricular hypertrophy and cardiomegaly. A chest x-ray usually reveals increased pulmonary blood and may show displaced pulmonary arteries. Echocardiography defines the anatomy, including theVSD, truncal valve function, and origin of the pulmonaryarteries.
Figure 144-5 Total anomalous pulmonary venous return. AO, Aorta; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; PA, pulmonary artery; PV, pulmonary vein; RA, right atrium; RV, right ventricle; SVC, superior vena cava.
Medical management is usually needed and includes anticongestive medications. Surgical repair includes VSD closure and placement of a conduit between the right ventricle and pulmonary arteries.
Total anomalous pulmonary venous return accounts for about 1% of congenital heart disease (Fig. 144-5). Disruption of the development of normal pulmonary venous drainage during the third week of gestation results in one of four abnormalities. All of the pulmonary veins fail to connect to the left atrium and return abnormally via the right side of the heart. They may have supracardiac, infracardiac, cardiac, or mixed drainage. An atrial-level communication is required for systemic cardiac output and survival.
The most important determinant of presentation is the presenceor absence of obstruction to the pulmonary venous drainage.Infants without obstruction have minimal cyanosis and may beasymptomatic. There is a hyperactive right ventricular impulse with a widely split S2 (owing to increased right ventricular volume) and a systolic ejection murmur at the left upper sternalborder. There is usually a mid-diastolic murmur at the lowerleft sternal border from the increased flow across the tricuspidvalve. Growth is relatively poor. Infants with obstruction present with cyanosis, marked tachypnea and dyspnea, and signs ofright-sided heart failure including hepatomegaly. The obstruction results in little, if any, increase in right ventricular volume,so there may be no murmur or changes in S2.
For infants without obstruction, the ECG is consistent with right ventricular volume overload. Cardiomegaly with
Figure 144-6 Hypoplastic left side of the heart. AO, Aorta; LA, left atrium; LV, left ventricle; PA, pulmonary artery; PDA, patent ductus arteriosus; RA, right atrium; RV, right ventricle.
increased pulmonary blood flow is seen on chest x-ray. Infants with obstructed veins have right axis deviation and right ventricular hypertrophy on ECG. On chest x-ray, the heart is normal or mildly enlarged with varying degrees of pulmonary edema that can appear similar to hyaline membrane disease or pneumonia. Echocardiography shows the volume-overloaded right side of the heart, right-to-left atrial level shunting, and common pulmonary vein site of drainage and degree of obstruction.
At surgery, the common pulmonary vein is opened into the left atrium, and there is ligation of any vein or channel that had been draining the common vein.