Pressure indices of myocardial oxygen consumption during pulsatile ventricular assistance.

Left ventricular (LVP) and intramyocardial (IMP) pressure indices were compared with left ventricular myocardial oxygen consumption (MVO2) during pulsatile ventricular assistance to determine if MVO2 can be predicted under conditions of ventricular support. During five acute anesthetized calf experiments, IMP and LVP were recorded for control and six conditions of support. The assisted conditions were asynchronous and synchronous, 1:1 or 1:2; each control mode with atrial uptake only or combined atrial and ventricular uptake. IMP was measured by implantation of a miniature pressure transducer in the midanteriolateral wall of the left ventricle. MVO2 was determined using the radioactive microsphere blood flow technique and blood gas data. Mean values of peak systolic pressure, maximum dP/dt, and integral of Pdt were calculated for IMP and LVP for each condition. Pressure indicators of left ventricular function were found to correlate well with MVO2 during conditions of pulsatile support.