Experimental studies on left ventricular assist circulation (LVAC) using our pulsatile flow roller-type pump were carried out. During left atrio-ascending aortic bypass, the effect on hemodynamics was examined under different bypass flow from 30 to 60ml/kg/min.
With the relatively low bypass flow of 40ml/kg/min or less, left ventricular and systemic pressure decreased about 50 per cent on the initiation of LVAC but recovered the control value within a few minutes as left ventricular pressure recovered. With bypass flow of 45 to 55ml/kg/min, remarkable diastolic augmentation was observed on central aortic pressure tracing. Left ventricular pressure decreased about 20 per cent and drop of central aortic pressure was not observed. With the bypass flow of 55 to 60ml/kg/min, cardiac output became zero and systolic segment of aortic pressure tracing disappeared and central aortic pressure was maintained well with only the blood pump action. But the decrement of left ventricular pressure remained 50 to 55 per cent of control value.