History
Children with partial anomalous pulmonary venous connection (PAPVC) usually remain asymptomatic and are referred based on an incidentally noted cardiac murmur. Symptoms may occur in older patients and may be secondary to right-sided volume overload or pulmonary vascular obstructive disease.
Determining the natural history of this condition was difficult before the era of direct cardiac imaging (ie, echocardiography, cardiac catheterization) because the diagnosis was made only postmortem.
The development of complications from PAPVC clearly depends on how many pulmonary veins abnormally return to the right heart. A single anomalous vein is not usually hemodynamically significant and, hence, does not produce any symptoms.
About 10% of patients with an atrial septal defect (ASD) also have PAPVC and may have symptoms of right-sided overload.
Dyspnea may occur in adults but is rare in children. A child may experience exercise intolerance as a symptom in cases in which more than 50% of pulmonary veins anomalously drain.
Palpitations may reflect cardiac arrhythmias, which are almost always supraventricular in origin. These arrhythmias may be due to right atrial dilatation and, hence, may present at older age. They can also occur postoperatively due to atriotomy.
Hemoptysis is a rare symptom that reflects either chest infection or the development of pulmonary vascular disease.
Chest pain may be evidence of right-heart ischemia but does not occur in childhood. More commonly, chest pain may be a manifestation of recurrent bronchitis.
Associated defects (either cardiac or extracardiac) can produce symptoms.
Peripheral edema can occur in adults with cardiac failure.
The severity of symptoms in scimitar syndrome depends on several factors, including degree of pulmonary hypertension and the severity and frequency of chest infections. Scimitar syndrome can present in neonates, children, and adults and is related to the degree of pulmonary hypoplasia.
Physical Examination
Physical examination findings in partial anomalous pulmonary venous connection (PAPVC) are usually more revealing than the history, but positive findings depend on the volume of abnormal pulmonary venous return to the right heart. If only a single vein is anomalous, the physical examination findings may be normal. In a patient with a larger volume of abnormal veins, physical examination findings are similar to those of an uncomplicated atrial septal defect (ASD).
Left parasternal lift reflects right ventricular dilation. Impulse in the second left intercostal space reflects pulmonary artery dilation.
A soft systolic ejection murmur is heard over the pulmonary area, reflecting turbulence in the pulmonary trunk due to increased right ventricular ejection volume. The second heart sound is always widely split but may have normal respiratory variation.
In healthy individuals, inspiration increases systemic venous return to the right heart, causing a delay in the pulmonic closure component of the second sound. This phenomenon also occurs in patients with PAPVC who have an intact atrial septum. [3] However, in patients with PAPVC and ASD, volume flow into the right heart is always increased, and respiration further augments that flow. Therefore, splitting of S2 proceeds from wide during expiration to wider during inspiration. This does not occur in patients with a significant ASD, in whom second heart spitting is wide and fixed. In the presence of an ASD, variations in systemic venous return during respiration are counterbalanced by reciprocal changes in flow through the ASD, maintaining total right ventricular flow more or less constant. A mid-diastolic murmur due to increased transtricuspid right ventricular filling may be heard over the tricuspid valve area at the lower left sternal border.
Cyanosis does not occur, even in older patients in whom pulmonary hypertension develops, because a right-to-left shunt cannot develop in the absence of an atrial septal communication.
Right-sided heart failure signs in adults include hepatomegaly, jugular venous distension, ascites, and peripheral edema.
Pulmonary vascular disease may occur in older adults, although this is rare. Clinical signs of pulmonary hypertension include a right ventricular parasternal lift, absence of systolic murmur, narrowly split S2 with a loud pulmonic component, and, occasionally, an early, high-frequency murmur of pulmonic regurgitation. Cyanosis does not occur in the presence of an intact atrial septum.
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Anomalous pulmonary venous return (APVR). Types of total anomalous pulmonary venous connection.
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Partial anomalous pulmonary venous return of the left lower pulmonary vein seen entering the innominate vein as demonstrated via echocardiogram (A) and angiogram (B).
