Submaximal oxygen pulse divided by body weight during incremental exercise test

The purpose of this study was to examine whether submaximal oxygen pulse divided by body weight (O2 pulse/BW) during an incremental exercise test discriminated between trained and untrained men, correlated to left ventricular ejection fraction (LVEF) at rest in post-myocardial infarction patients, and was sensitive and specific in detecting ventricular dysfunction and mild ventricular dysfunction with myocardial ischemia during exercise. Forty-three trained men, 44 untrained men, and 21 post-myocardial infarction patients pedaled a cycle ergometer, with O2 consumption, heart rate, and myocardial ischemia monitored during the exercise test. Work rate started at 10 W and increased 10 W/min stepwise; the O2 pulse and O2 pulse/BW at 10 through 120 W were calculated. The LVEF of the patients was measured at rest using radionuclide ventriculography three weeks after myocardial infarction. The results revealed that O2 pulse/BW was significantly different between trained and untrained men at 80, 90, 100, 110, and 120 W, whereas O2 pulse was significantly different only at 110 and 120 W. Oxygen pulse/BW at 10 W, as well as 30 through 120 W, significantly correlated to LVEF in the patients. The three patients with ventricular dysfunction (LVEF, < 40%) plus the two patients with mild ventricular dysfunction (LVEF between 40 and 50%) and ST segment depression during exercise all had submaximal O2 pulse/BW significantly lower than untrained men (sensitivity, 100%). Among the 11 patients with normal ventricular function (LVEF, > 50%) plus the 5 patients with mild ventricular dysfunction but no ST segment depression, 13 patients did not have submaximal O2 pulse/BW significantly lower than untrained men (specificity, 81%).