[Inverse relationship between coronary flow velocity and myocardial oxygen extraction during intracoronary infusion of papaverine].

The relationship between coronary blood flow velocity (CBFV) and myocardial oxygen extraction (O2-Ext) was investigated during rapid changes of CBFV after intracoronary papaverine infusion. In 6 patients without stenosis of the left anterior descending artery (LAD), one with hypertrophic cardiomyopathy, 2 with syndrome X and 3 with effort angina pectoris, simultaneous measurements of CBFV using the Doppler catheter system and coronary venous oxygen saturation using the fiberoptic catheter system were continuously performed before and during intracoronary infusion of papaverine. When O2-Ext was related to CBFV in every cardiac cycle, there was a good, inverse linear relationship, both in the increase (r = 0.81 +/- 0.24) and decrease (r = 0.93 +/- 0.04) phases of CBFV. The increase in cross-sectional area of segment 6 in the LAD as observed on orthogonal coronary angiograms was 6.0 +/- 2.0%. These results imply that the increase in CBFV during intracoronary papaverine infusion seems parallel to that of coronary blood flow, and that papaverine induces no significant change in myocardial oxygen consumption. Myocardial oxygen extraction in response to changes in coronary flow is regulated readily to meet the myocardial oxygen demand.