The A wave of the apex cardiogram in idiopathic hypertrophic subaortic stenosis.

Abstract

The apex cardiogram showed abnormally large A waves in 8 out of 9 patients with idiopathic hypertrophic subaortic stenosis. The A waves were above normal width in 7 out of 8 patients. The isometric contraction time was prolonged in 8 of the 9 patients in whom this measurement could be made. The height of the A wave showed no correlation with the end-diastolic left ventricular pressure; it also showed no correlation with the systolic gradient in the left ventricle. While not all records in subaortic stenosis show a very large A wave, its presence should alert the observer to the possibility of this diagnosis. A tall A wave may be related clinically to a palpable bulge just preceding the main apex impulse and thus producing a souble pulsation at the apex.