Hemodynamic consequences of a swinging, infarcted ventricular septum

Noonan syndrome presents with dysmorphic facial features, short stature, and cardiac abnormalities (most commonly pulmonic stenosis and hypertrophic cardiomyopathy). This report describes a rare case accompanied by a secundum atrial septal defect (ASD) and a ventricular septal aneurysm causing right ventricular (RV) pressure gradient. A 29-year-old mentally retarded man was admitted to hospital with exertional dyspnea. His somatic features included short stature (148 cm), hypertelorism, a shield chest, and thoracic scoliosis. Echocardiogram showed a secundum ASD with bidirectional shunting and a ventricular septum bulging toward the left ventricle in diastole, and then toward the RV in systole causing obliteration of the RV. The peak pressure gradient measured across the RV outflow by continuous wave Doppler was 30 mmHg. Cardiac catheterization revealed an elevated RV pressure without pulmonary hypertension and confirmed the pressure gradient. Right ventriculography revealed the septal excursion toward the RV in systole, leaving only a small residual cavity in the inflow and outflow regions of the RV. The ASD was closed with an autologous pericardial patch. A thin, fibrous portion of the ventricular septum was resected and replaced with a Dacron patch. From the histological examination, the RV cavity obliteration turned out to be produced by the excursion of the infarcted ventricular septum.