Fibrinolytic enzyme system.

M "JOULMitral valvular inefficiency, manifest as regurgitation in the presence of atrial fibrilla- tion, supports this hypothesis.Clearly, as the atrial filling curve moves to the left with exercise as heart rate increases and diastole shortens, atrial contraction assumes less importance in valve closure.The conclusion must be that at slow and probably at resting heart rates atrial contraction is indispensable to normal (high) mitral valve efficiency.Provision of a contracting atrial chamber would seem to be an essential part of an artificial heart design that utilizes a leaflet valve at the atrioventricular junction and which operates at near normal heart rates.-