Effects of exercise training on left ventricular mass in patients with ischemic heart disease

To determine whether exercise training results in increased left ventricular mass in patients with ischemic heart disease, we obtained echocardiograms in 14 coronary patients before and after an average of seven months (range 3 to 14 months) of supervised arm and leg exercise. Each echocardiogram was interpreted jointly by two blinded observers, using three different measurement conventions and a semiautomated method of analysis to minimize errors of interpretation. Exercise training led to subjective improvement in all 14 patients, and to an objective increase in functional capacity in 13 of 14 patients, as evidenced by an increase in maximal oxygen consumption estimated from symptom-limited treadmill exercise testing (8.8 +/- 2.7 (SD) and 10.7 +/- 2.5 METS before and after training, respectively, p less than 0.01). However, this functional improvement was not accompanied by any significant change in left ventricular end-diastolic diameter, or posterior wall or interventricular septal thickness. Likewise, left ventricular cross-sectional area (CSA), an index of left ventricular mass which corrects for altered ventricular volume and theoretically reflects directional changes in mass despite nonuniform wall thickness, did not change significantly after training by any measurement convention (CSA = 18.0 +/- 6.5 and 17.6 +/- 6.5 cm2 before and after training, respectively, by American Society of Echocardiography measurements). These data strongly suggest that improved functional capacity after exercise training in patients with ischemic heart disease is not due to exercise-induced left ventricular hypertrophy.