Left ventricular cavity obliteration: hemodynamic behavior of the postextrasystolic beat

Abstract

Thirteen patients with angiographic left ventricular cavity obliteration are analyzed. No transvalvular or subvalvular gradients were present except in two cases with a mild gradient after amyl nitrite inhalation. The commonest clinical features were chest pain (60%) and dyspnea (23%). Electrocardio-graphically proved left ventricular hypertrophy (70%) was prominent. The echocardiograms showed asymmetric septal hypertrophy (40%), symmetric hypertrophy (20%), systolic anterior motion of the anterior leaflet of the mitral valve (60%), and mitral valve prolapse (20%). In all the patients changes in systolic intraventricular pressure in the post-extrasystolic beat were evaluated and a decrease in intraventricular pressure was found in every case. In the four cases with extrasystoles recorded in the aorta a similar decrease of aortic pressure was found. This behavior is completely different in the hypertrophic cardiomyopathy with obstruction to the left ventricular outflow tract, where there is an increase in intraventricular pressure and a decrease in aortic pressure in the postextrasystolic beat. Left ventricular cavity obliteration is an angiographic phenomenon which is common in hypercontractile states, being an usual finding in hypertrophic cardiomyopathy. In cases without obstruction to the left ventricular outflow tract, the decrease in aortic pressure is caused by a different mechanism than the one involved in cases with obstruction. In cases without obstruction, the decrease in post-extrasystolic aortic pressure corresponds to a decrease in intraventricular pressure, whereas in subaortic stenosis there is an increase both of intraventricular pressure and gradient with the subsequent decrease in aortic pressure.