INFLUENCE OF EXERCISE TRAINING SOON AFTER MYOCARDIAL-INFARCTION ON REGIONAL MYOCARDIAL PERFUSION AND RESTING LEFT-VENTRICULAR FUNCTION

There is scant information regarding the effect of exercise training begun soon after hospital discharge for myocardial infarction (MI) with respect to subsequent improvement in exercise tolerance, enhancement of regional myocardial perfusion, or left ventricular function. Accordingly, 19 post-MI patients (mean age 53 +/- 7 years) underwent treadmill exercise quantitative thallium-201 (Tl-201) scintigraphy and rest radionuclide angiography (RNA) prior to and after 12 weeks of thrice-weekly exercise training which was targeted to 70-85% of maximum exercise heart rate achieved. Training was begun at 25 +/- 3 days after hospital discharge. Eight Tl-201 scan segments were each scored from 1-6 points based upon uptake and washout criteria with 6 being the most severe defect (> 50% reduction in Tl-201 events with no delayed redistribution). When matched to the pretraining peak workload on exercise testing, 12 weeks of training significantly lessened heart rate (120 +/- 4 to 97 +/- 4, p < 0.001), peak systolic blood pressure (142 +/- 6 to 129 +/- 5 mmHg, p < 0.01), and significantly reduced double product [17.2 +/- 10.8 to 12.7 +/- 9 (x 10(3)), p < 0.001]. Training was associated with a reduction of exercise-induced ST depression or angina (42 to 16%) which was not statistically significant. The mean resting by RNA ejection fraction was 50 +/- 3% prior to training and 51 +/- 3% after training. There was no significant change in overall Tl-201 defect score or the number of defect regions per patient scan comparing pre- and posttraining scintigrams. Of the 5 patients who had elimination of exercise-induced angina or ischemic ST depression after training, none showed an improvement in the Tl-201 defect score between the two studies. Thus, 3 months of exercise conditioning begun soon after acute MI is associated with a significant training effect without an improvement in resting left ventricular function or myocardial perfusion at peak exercise.