CORONARY BACK FLOW PRESSURE IS ELEVATED IN ASSOCIATION WITH INCREASEDLEFT-VENTRICULAR END-DIASTOLIC PRESSURE IN HUMANS

To clarify the effect of left ventricular (LV) diastolic pressure on t he coronary pressure-flow relation in humans, the instantaneous diasto lic coronary pressure-Doppler flow velocity relation was analyzed at r est and during papaverine-induced maximal vasodilation in 15 patients with angiographically normal coronary arteries. The values for slope ( alpha PF) and zero-flow pressure intercept (Pzf index) of the instanta neous diastolic coronary pressure-flow velocity relation were obtained by a linear regression analysis. Although aPF did not correlate with LV end-diastolic pressure (EDP), the Pzf index correlated positively w ith LVEDP both at rest and during maximal vasodilation (r=0.64, P < 0. 05 and r=0.58, P < 0.05, respectively). Thus, the back pressure to cor onary inflow, as indicated by the Pzf index, may be elevated in patien ts with increased LVEDP, resulting in the rightward shift of the maxim ally dilated coronary pressure-flow relation and decreased maximal cor onary flow and reserve at any given perfusion pressure.