[Measurement of regional and global coronary sinus blood flow with the continuous thermodilution technique. II. Clinical studies in patients with coronary heart disease (author's transl)].

Coronary sinus blood flow, great cardiac vein flow, myocardial oxygen consumption and myocardial lactate extraction were measured in 38 patients (12 female, 26 male) at rest and during supraventricular pacing until angina or av block occurred. 17 patients without significant coronary artery stenosis in the angiogram built the control group (group I). 15 patients had 2- or 3-vessel disease (group II), 6 exhibited an isolated LAD-stenosis of 80 to 95% cross section area (group III). There were no significant differences at rest between the 3 groups. Whereas pressure-heart rate product, coronary sinus blood flow and great cardiac vein flow, increased significantly during pacing in group I and II, there was only a slight increase in great cardiac vein flow from 77 +/- 22 to 83 +/- 19 ml/min in group III. Flow/beat only in this group declined significantly from 1.07 +/- 0.2 at rest to 0.68 +/- 0.1 ml during pacing (p less than 0.001). Coronary reserve capacity of these patients is probably reduced at rest, and flow during pacing can increase only insufficiently. Because rate-pressure product during pacing rose significantly, myocardial oxygen demand rose as well. The fact of a significant myocardial lactate production during pacing in group III indicates that increased myocardial oxygen demand in this group could not be adequately supplied. Also patients in group II produced lactate during pacing in contrast to patients of group I. So, if blood flow in the individual may be similar in patients with and without coronary artery disease, simultaneous measurements of myocardial lactate extraction can discriminate between both groups.