Abstract
Bulk and regional mechanics of the left ventricle during pumping of a left ventricular assist device (LVAD) implanted between the left ventricular apex and descending thoracic aorta (apical bypass) were studied by in vivo acute experiments on mongrel dogs having ischemic hearts using implantable miniature sonomicremeters. Hemodynamic and mechanical effects of the apical bypass method were compared with those of the atrial bypass method in which LVAD was implanted between the left atrium and descending thoracic aorta. Hemodynamic parameters, mechanical works and endocardial viability ratio observed under pump-off condition were lowest or highest at 1 to 2h after ligating the left anterior descending coronary artery, although they showed a tendency of recovery 3h later. These results indicate that the apical bypass method is more effective than the atrial bypass method in the abilities not only of the circulatory assist and ventricular unloading but also of the recovery of cardiac function.
