Exercise test in acute myocardial infarction

Although maximal oxygen consumption (Vo(2)max) and oxygen consumption at anaerobic threshold (Vo(2)AT) were used to measure cardiac function, the clinical significance in acute myocardial infarction (Mi) has not been reported, The purpose of this study was to compare Vo(2)max and Vo(2)AT between post-MI patients rind healthy men and to correlate the parameters to other clinical measures. Forty-three active healthy men, 44 sedentary healthy men, and 43 post-Mi patients were studied using incremental cycle exercise test. Their work rates, oxygen consumption, heart rates, oxygen pulses, ventilation, and other parameters at Vo(2)max and Vo(2)AT were determined with spirometer, gas concentration analyzer, and electrocardiograph. Anaerobic threshold was determined by analyzing the ventilatory parameters. Most of the exercise test parameters at Vo(2)max were greatest in the active men, intermediate in the sedentary men, and least in the post-MI patients (P < 0.01) whereas the rate-pressure products of the active men and sedentary men were not significantly different from each other and were greater than those of the post-Mi patients (P < 0.01). in the post-MI patients, Vo(2)max was inversely correlated to the peak serum level of creatine phosphokinase MB isoenzyme (P < 0.01) and associated with extensive infarction (P < 0.05). Most of the parameters at Vo(2)AT were greater in the active men than in the sedentary men (P < 0.01) but not significantly different between the sedentary men and post-MI patients. In the post-MI patients, Vo(2)AT was significantly correlated to left ventricular ejection fraction (P < 0.01) and associated with heart failure (P < 0.05). The results revealed that Vo(2)max and Vo(2)AT had different clinical: significance in post-MI patients; Vo(2)max was related to the infarct size, and Vo(2)AT was related to the pumping function of heart.