A computer-controlled aortic and mitral valve occluder.

To study cardiac mechanics, it is important to study the beat-to-beat changes in the heart. Left ventricular diastolic filling properties are determined by a passive component and an active component due to ventricular relaxation that occur simultaneously. To separate the active and passive components of ventricular filling, we designed a computer-controlled mitral valve occluder that prevents left ventricular filling. A computer-controlled aortic occluder was designed to change afterload conditions that could affect the components of ventricular filling. Experiments in six dogs demonstrated that these devices effectively control ventricular inflow and ejection on a beat-to-beat basis. The computer-controlled aortic and mitral occluders have a more accurate triggering and occlusion timing system than the previously reported techniques. This computer-controlled device enabled us to separate the passive component of filling from the active component, ventricular relaxation, and to alter afterload simultaneously, which will allow us to develop a better understanding of how ventricular filling and ejection is controlled on a beat-to-beat basis.