Effect of dynamic cardiomyoplasty on coronary arterial blood flow

: We investigated whether or not dynamic cardiomyoplasty adversely affected coronary arterial blood flow (CABF) through compression of the coronary arteries by muscular contraction during systole and incomplete relaxation of the skeletal muscle flap during diastole. Dynamic cardiomyoplasty was performed in 20 mongrel dogs using a left latissimus dorsi muscle flap, paced synchronously with the R wave of the electrocardiogram. A Doppler catheter (3 F in diameter) was placed in the left main trunk of the coronary artery to analyze the instantaneous changes of coronary arterial blood flow velocity by fast Fourier transformation analysis. We compared both systolic and diastolic properties during assisted versus unassisted cardiac cycles by calculating the peak velocity and the time velocity integrate (TVI). A significant enhancement of systolic CABF was recognized by increases in the systolic peak velocity (26.5 +/- 29.2%) and TVI (20.2 +/- 38.6%). The improved systolic CABF was consistent with an increase in systolic aortic pressure (15.5 +/- 4.3%) and stroke volume (42.8 +/- 11.2%). CABF was also enhanced in diastole because a significant increase of diastolic peak velocity (4.4 +/- 9.4%) and TVI (11.0 +/- 16.7%) was observed. Enhancement of diastolic CABF was associated with the augmentation of cardiac function and the reduction of left ventricular end-diastolic pressure. It could be concluded that CABF was increased by the enhancement of cardiac function as a result of dynamic cardiomyoplasty leading to an increase of cardiac output and aortic pressure and a decrease of left ventricular end-diastolic pressure.