PULMONARY ATRESIA INTACT SEPTUM

Pulmonary atresia with intact ventricular septum is a diagnostic consideration in neonates and infants with cyanosis, a dominant left ventricle, and reduced pulmonary blood flow. When the right ventricle is small, the physical examination reveals an isolated left ventricular impulse and either no murmur at all or a soft aortic midsystolic flow murmur.

The electrocardiogram shows right atrial P waves, a vertical QRS axis with clockwise depolarization,and adult QRS progression in the precordial leads.An initially normal radiologic cardiac silhouette increases because of moderate enlargement of the right atrium and left ventricle.

The lung fields are oligemic, and the main pulmonary artery segment is normal.

Echocardiography with color flow imaging and Doppler interrogation identifies an imperforate pulmonary valve, a well-formed pulmonary trunk, a small thick-walled right ventricle, a small tricuspid valve, and moderate enlargement of the right atrium and left ventricle.

A dilated right ventricle with tricuspid regurgitation is characterized on physical examination by a right ventricular impulse and a tricuspid regurgitant murmur that radiates to the right of the sternum.

The electrocardiogram shows strikingly tall peaked right atrial P waves. The QRSaxis is rightward with clockwise depolarization. Right ventricular hypertrophy is reflected in tall right precordial R waves.

The x-ray reveals a cardiac silhouette that virtually fills the chest because of massive dilation of the right atrium and right ventricle.

The echocardiogram with color flow imaging and Doppler interrogation identifies a dilated right ventricle, an Ebstein’s-like malformation of the tricuspid valve, severe tricuspid regurgitation,and striking enlargement of the right atrium.