First heart sound in atrial septal defect.

This is a retrospective study of 25 patients with secundum-type of ASD, confirmed by catheterization and angiocardiography. As controls, 25 normal subjects of matching age were studied. The phonocardiograms and carotid pulses of the 2 groups were recorded and compared. Special attention was paid to the interval between the 2 main components (Ia and Ib) of the first heart sound, to the amplitude of both Ia and Ib, and to the relationship between carotid upstroke and first heart sound. All intervals between sound components of the patients with ASD were found similar to those of the controls. No increase in amplitude of Ib could be documented. The amplitude of the first heart sound relative to that of the second sound (measured from the ratio I/IIA) was similar to that of the controls, Finally, a slight precedence of aortic valve opening (obtained from the carotid upstroke time minus transmission time) over the second component of the first sound (Ib) was found both in ASD and in controls. In view of these facts, a tricuspid contribution to the mechanism of the b component of the first heart sound appears highly unlikely. On the other hand, this component seems closely related to the dynamic events (blood acceleration and walls deceleration in the aortic root) that follow the aortic valve opening.

Abnormal left ventricular contraction revealed by impedance cardiograms and arterial tracings in bundle branch blocks and old myocardial infarcts.

Following the observation of an unusual pattern of the first derivative of the impedance cardiogram in cases of bundle branch block, a systematic study was performed both in normal controls and clinical cases. This graphic study was supplemented by the simultaneous recording of the first derivative of an arterial tracing, preferably the indirect aortic pulse at the suprasternal notch. These studies were performed in 70 subjects: 30 normal subjects, 14 cases of right bundle branch block, 14 cases of left bundle branch block, and 12 cases of old infarcts. Out of 30 normal subjects, only 2 old persons showed splintering of the main systolic wave. Both right and left bundle branch blocks had in common either a splitting of this wave in 2 peaks or multiple splintering; however, 4 cases in each type of bundle branch block had a normal pattern. Among old infarcts, 7 had a splitting, 3 had multiple splitting, and 2 had a normal pattern. The derivative of the arterial tracings showed a remarkable similarity with that of the impedance cardiogram, revealing that abnormal left ventricular ejection (dyssynergy) was present in all 3 types of lesion. The first derivative of the impedance cardiogram was often more typical than that of the arterial tracings, because it had fewer secondary vibrations or artifacts. Thus, the former seems more sensitive to diagnosing left ventricular abnormalities of contraction, even when the electrocardiogram is normal.