Novel left ventricular assist systems I and II for cardiac recovery: the driver.

We have recently described the Novel Left Ventricular Assist Systems (Novel LVAS) I and II, which avoid cannulation of cardiac chambers and synchronize pumping with the patient's electrocardiogram. We now describe the drive system in more detail. The drive unit is an air-driven pulsatile system. The driver's parameters can be programmed. This electro-pneumatic unit contains 3 modules. A remarkable feature of the driver system is that it contains 2 pneumatic units that alternate in their function every 15 minutes. This prevents overheating and component fatigue or failure, and it enables the use of smaller units. If one of the units fails, an alarm will warn of the problem, and the other will continue indefinitely. This LVAS is synchronized with the patient's ECG, which enables it to eject the stroke volume during diastole and in this way to act as a chronic counterpulsator. We have designed the Novel LVAS to operate at a low-frequency rate. This fact, together with the electrocardiographic synchronization, offers the best prospect for myocardial recovery in patients who are also receiving beta-adrenergic blocking agents. This dual therapy will help adjust heart rate to pump frequency.

Congenital mitral-aortic discontinuity.

Mitral-aortic (M-A) discontinuity is an uncommonly observed congenital malformation. From the embryologic point of view, it is a failure of the superior endocardial cushion of the A-V canal reach and insert into the aortic root (the mitral-aortic fibrous trigone). It should be differentiated from aorto-left ventricular discontinuity, a complication of endocarditis with excavating abscesses without boundaries. In congenital mitral-aortic discontinuity, the anterior leaflet of the mitral valve fails to insert into the aortic root. We report our experience with 2 patients. In patient 1, the severe left ventricular outflow obstruction was mainly caused by the mobile anterior leaflet of the mitral valve.