Reduced coronary collateral resistances after chronic ventricular sympathectomy

Previous work has suggested that chronic ventricular sympathectomy causes a reduction in coronary collateral resistances. In the present experiments an isolated dog heart procedure was used to directly measure directional collateral resistances in 12 acutely denervated controls and 8 hearts that had undergone ventricular sympathectomy 2 wk earlier. In the procedure, the major coronary arteries were perfused separately but simultaneously during maximum vasodilation, and collateral resistances supplying the vascular beds of the arteries were determined by the double retrograde flow method. In the sympathectomized hearts, all collateral resistances were 47--65% less than in the controls (P less than 0.05). Also, in all hearts, minimum antegrade coronary resistances were determined from pressure-flow relationships in the major coronary arteries. Minimum coronary resistances in the 2 groups were not significantly different (P greater than 0.05). These results indicate that 2 wk of ventricular sympathectomy indeed causes a reduction in coronary collateral resistances, but has no effect on coronary resistances.