Short-term physical training reduces left ventricular dilatation during exercise soon after myocardial infarction

Coronary heart disease and beta-blocker treatment can increase thr use of t he Frank-Starling mechanism during exercise. The aim of the study was to as sess whether this could be influenced by physical training. Male patients o n beta-blocker treatment after myocardial infarction were randomised to fou r weeks of training (ET, n = 19) or to a control group (Ctr, n = 18). Cardi ac output (CO) at rest and at identical submaximal exercise levels in each patient were determined by radionuclide ventriculography at baseline and af ter the intervention period. CO was calculated as end diastolic volume (EDV ) x ejection Fraction x heart rate, and Delta CO and Delta EDV as change in parameter from rest to exercise. The mean (SD) Delta CO decreased from 6.5 (2.1) L/min(-1) to 5.1 (2.4) in ET patients and increased from 5.0 (1.7) t o 5.8 (2.7) in Ctr, p = 0.003. Delta EDV decreased from 30 (30) mt to 12 (3 5) in ET and increased from 11 (20) to 36 (33) in Ctr, p = 0.005. When adju sting for baseline dissimilarities between the groups in a multivariate lin ear regression analysis, these differences were still statistically signifi cant, p = 0.018 and p = 0.044, respectively. Physical training reduces the CO increase needed to perform identical submaximal exercise, and this is ac companied by less left ventricular dilatation, with a potential for reducin g exercise-induced ischaemia.