Effect of prolonged intense endurance training on systolic time intervals in patients with coronary artery disease

We studied the effect of exercise training (ET) on systolic time intervals (STI) in 13 patients with coronary artery disease (CAD). All patients trained for at least 10 months. They exercised three times/week at 50% to 70% of maximal oxygen uptake (V̇O₂max) for the initial 3 months and at least four times/week for approximately 50 minutes at 70% to 90% of V̇O₂max thereafter. A significant training effect was documented by an increase in V̇O₂max from 26.0 ± 4.3 to 37.2 ± 5.8 ml/kg/min (p < 0.01), a lower heart rate (HR) at rest, and a lower blood pressure and HR during submaximal work. The indices of total electromechanical systole (QS₂I) and left ventricular ejection time (LVETI) did not change. However, pre-ejection period index (PEPI) decreased from 137 ± 9 msec to 129 ± 9 msec (p < 0.01). PEP LVET decreased from 0.373 ± 0.028 to 0.342 ± 0.032 (p < 0.01). Left ventricular end-diastolic dimension and posterior wall thickness, measured echocardiographically, were increased after training. We conclude that exercise training may improve myocardial performance in some patients with CAD.