THE TRIAD OF CYANOSIS, DECREASED PULMONARY VASCULARITY AND CARDIOMEGALY: Clinical, Pathologic, and Physiologic Considerations

Abstract

The clinical findings in patients with the triad of cyanosis, cardiomegaly, and decreased pulmonary vascular markings are discussed as they relate to severe Ebstein's anomaly of the tricuspid valve, severe pulmonic valve stenosis, and pulmonic valve atresia with an intact ventricular septum. These entities may have certain pathologic anatomic features in common, including a right ventricle with a smaller functional capacity than normal, malformations of the tricuspid valve, hypoplasia of the pulmonary vascular bed, an enlarged right atrium, and right ventricular outflow tract obstruction. Similarly, these disorders often have a common pathophysiology, which includes impedance to right heart flow causing decreased pulmonary flow, a right-to-left shunt at the atrial level with peripheral arterial desaturation, tricuspid valve regurgitation, and right atrial hypertension. Since the infants under discussion often are gravely ill, decisions regarding their care may have to be made on the basis of clinical information alone without performing the definitive laboratory procedure, right ventricular selective angiocardiography. The clinical features that should alert the radiologist to the diagnosis of Ebstein's anomaly are that the defect is compatible with life to middle age, cyanosis in the neonatal period improving or disappearing with time, and an electrocardiogram showing arrhythmias, Wolff-Parkinson-White syndrome or right bundle branch block, prolonged PR and QRS intervals, and neither left nor right ventricular hypertrophy. Severe pulmonary valve stenosis is suggested when clinical information includes distress early in life in a cyanotic child with superior physical development and a harsh systolic murmur. The electrocardiogram typically shows severe right ventricular hypertrophy and “strain,” particularly as the child gets older. Pulmonic valve atresia should be suspected when a cyanotic child has congestive heart failure within the first few days or weeks of life, with intense cyanosis. The second sound is single, and the electrocardiogram may show left ventricular or right ventricular hypertrophy. With the plain film findings, this clinical information should permit a logical diagnosis, often before selective right ventricular angiocardiography.