Auscultatory Findings in Patients with a Small Ventricular Septal

characteristics of ventricular septal de-fects have been the subject of several studies,'-5 none of them dealing specifically with the features of small defects. The pres-ent study represents an attempt to define the phonocardiographic pattern of ventricular septal defect with a small left-to-right shunt and normal pulmonary artery pressure. It was hoped that this might provide the clini-cian with a means of differentiating the mur-mur of a small ventricular septal defect from the " innocent " or " functional " murmur and from the murmur of mild infundibular pul-monic stenosis. Material and Methods Twenty-one patients with small ventricular sep-tal defects form the basis of this report. All were proved at cardiac catheterization to have a left-to-right shunt resulting in a pulmonary blood flow less than twice the systemic flow. Pulmonary artery pressures were normal in all. Twelve pa-tients (group 1) had identical right ventricular and pulmonary artery systolic pressures and nine (group 2) had a slight gradient of less than 20 mm. Hg across the infundibulum of the right ventricular outflow tract. Ten patients were male, 11 were female. Their ages varied from 1 to 22 years. They were all completely asymptomatic and had normal electrocardiograms and roentgeno-grams. All patients were carefully examined and phono-cardiograms were obtained in all. In two instances the Sanborn Twin-Beam apparatus was used; in the rest of the patients the phonocardiograms were obtained by means of a new Sanborn Poly-Beam recorder. * The tracings were recorded in the re-cumbent position, at a paper speed of 100 mm. per second. As reference tracings the electrocardio