[On the behavior of the atrioventricular valves in AV blocks. Polygraphic and echocardiographic study]

By means of echocardiography, phonocardiography and jugular venous pulse recording, we have investigated 8 patients with atrio-ventricular conduction disturbances of various degrees: 4 with a first-degree AV block; 3 with complete heart block; 1 with type 1, 2nd degree AV block. The pattern of mitral valve motion at M-mode echocardiography suggests that the leaflets of the atrioventricular valves are definitively closed in diastole, only by the ventricular contraction. The simultaneous recording of echocardiogram and phonocardiogram in complete heart block seems to indicate that the increased intensity of the first heart sound is not always due to the increased velocity of valve closure, but also to the sudden vibration of the atrial floor, which is put under undue tension by the simultaneous atrial and ventricular contraction.