Development and use of a remote-controlled mitral valve.

A remote-controlled mitral valve was designed and constructed to occlude the mitral or tricuspid orifice at any time in the cardiac cycle. It is used to study ventricular properties in the anesthetized dog by controlling ventricular filling, atrial properties by controlling atrial emptying and interaction of the two chambers by uncoupling them. The device can produce transient or steady-state perturbations in filling volume which make possible studies of intrinsic control of cardiac output. When filling volume is transiently reduced, stroke volume and end-systolic volume are reduced. A compensatory increase in stroke volume of the next cycles occurs due to increased ventricular preload and reduced afterload. The compensation continues until the lost stroke volume is regained, at which time the system returns to its previous steady state.