Evaluation of regional myocardial perfusion and ischemia from coronary venous blood

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Abstract
The usefulness of simultaneous great cardiac vein (GCV) and coronary sinus (CS) blood sampling for detecting regional differences in flow per unit weight (F/W) and metabolism was examined in the canine left ventricle. In normally perfused ventricles, F/W in myocardium represented in GCV and CS drainage agreed within .+-. 10% over a wide range (23-355 (ml/min)/100 g); GCV and CS PCO2 [partial pressure of CO2], and percent lactate extraction differed by 0.45 .+-. 1.5 (SD) mmHg, 0.002 .+-. 0.014 units and 0.3 .+-. 5.4%, respectively. GCV F/W exceeded CS F/W by > 10% during selective increases in left anterior descending (LAD) inflow or reductions in left circumflex (LC) inflow; it was > 10% below CS F/W during reduced LAD inflow or augmented LC inflow. GCV-CS differences in PCO2, pH and percent lactate extraction increased noticeably during reduced LAD inflow, averaging 5.7 .+-. 3.9 mm Hg, -0.037 .+-. 0.036 units and -25 .+-. 14%. Similar but directionally opposite changes occurred during reduced LC inflow (-5.8 .+-. 3.5 mm Hg, 0.035 .+-. 0.032 units and 26 .+-. 17%). Blood sampled near the origin of the GCV reflects perfusion in myocardium supplied virtually entirely by the LAD. GCV-CS differences that exceed normal values reflect increased heterogeneity of left ventricular perfusion and/or metabolism independently of the absolute values of the parameters measured.