Phonocardiographic analysis of diastolic flow murmurs in secundum atrial septal defect and ventricular septal defect.

The presence oflow frequency diastolic murmurs, presumably due to increased flow through the respective atrio-ventricular valves, has been recognized in patients with atrial and ventricular septal defects for many years. The murmur in ventricular septal defect was reported by Laubry and Pezzi in 1921 and emphasized by Wood (1950). A publication from this institute drew attention to this phenomenon in atrial septal defect (Nadas and Alimurung, 1952). The time of onset of this "rumbling" diastolic murmur was of some interest to one of us, and the clinical impression that the "flow rumble" of atrial septal defect occurs relatively early in ventricular diastole has been mentioned (Nadas, 1963). The present study was undertaken to investigate, by