Myocardial anaerobiosis in anemia in urémic man

Myocardial anaerobic metabolism (lactate production) has been previously observed in man primarily in ischemic heart disease. Myocardial lactate balance was studied in severe anemia in 6 stable uremic patients receiving maintenance hemodialysis before and after transfusion. They were young, aged 21 to 31, and had no evidence of heart disease or angina pectoris. At rest, the mean extraction coefficient for lactate by the myocardium (A-V/A)_L was abnormally low at -1.2 percent (range 14.3 to -18.9 percent). Intravenous isoproterenol infusion (2 to 8 μg/min) resulted in definite anaerobiosis in all patients, mean (A-V/A)_L -29.9 percent (range -1.5 to -76.5 percent). After transfusion, the extraction coefficient at rest was normal, mean 22 percent (range 11 to 39 percent), and decreased with isoproterenol infusion but remained positive in 5 of 6 patients. Electrical pacing (mean heart rate 148 beats/min) before transfusion increased the average extraction coefficient from 5.9 percent at rest to 7.9 percent; after transfusion, extraction increased from 22.9 percent to 34.3 percent. Exercise changes were not significant. Lactate/pyruvate ratio tended to increase from artery to coronary sinus during stress, before transfusion. There was improvement in the extraction coefficient for lactate with transfusion, without alteration of the uremic state. Cardiac index and systolic ejection rates indicated a hyperkinetic circulation at rest, increased by isoproterenol and exercise, and decreased by transfusion. Compensatory myocardial anaerobiosis may thus occur in physiologically stable anemic uremic patients with normal hearts and without development of angina.