The effect of left ventricular systolic function on maximal aerobic exercise capacity in asymptomatic patients with coronary artery disease

Abstract

The purpose of this study was to examine the relationship between maximal O2 uptake (V̇O2max) and left ventricular systolic function in patients with coronary artery disease. We studied 27 patients, age 50 ± 10 years (mean ± SD), who were asymptomatic and able to attain true V̇O2max. V̇O2max was defined the leveling-off criterion and/or respiratory exchange ratio of 1.15 or greater. Left ventricular ejection fraction was determined by gated cardiac blood pool imaging. In patients whose ejection fraction decreased with exercise, V̇O2max was 21 ± 4 vs 27 ± 4 ml/kg/min in those whose ejection fraction increased (p < .025). Left ventricular exercise reserve, i.e., the change in ejection fraction from rest to exercise, correlated with V̇O2max (r = .77, p < .0002), maximal O2 pulse (r = .50, p < .005), and maximal heart rate during treadmill exercise (r = .61, p < .001). Maximal heart rate during treadmill exercise correlated with V̇O2max (r = .70, p < .0002). These data suggest that impaired left ventricular function can limit V̇O2max and that maximal heart rate and left ventricular exercise reserve are among the variables affecting V̇O2max in patients with coronary artery disease who are not limited by angina.