Determining the most important parameters affecting exercise performance, particularly in relation to age, could have important implications for rehabilitation. Although a reduction in maximal heart rate is known to be important, previous studies have implied that left ventricular systolic function did not correlate with maximal exercise time.
2867 patients undergoing exercise echocardiography at a large tertiary center in Minnesota underwent routine echocardiographic assessments of left ventricular systolic and diastolic function. After multivariate adjustment, diastolic dysfunction was found to strongly and inversely associate with exercise capacity; compared to those with normal function, those with mild resting diastolic dysfunction managed 0.70 fewer metabolic equivalents (METs )(95% Confidence Interval [CI] -0.88 to -0.46; P<0.001), and those with moderate/severe resting diastolic dysfunction managed 1.30 fewer METs (95% CI -1.52 to -0.99; P<0.001). However, left ventricular systolic function did not correlate with exercise capacity. Other independent correlates of exercise capacity were age, female sex, and body mass index greater than 30 (p<0.01 for each).
This study further emphasizes the importance of diastolic dysfunction. Importantly, diastolic dysfunction is potentially modifiable through aggressive blood pressure control and attempts to decrease coronary artery disease. Prospective studies examining the ability of medications, such as dugs working on the renin-angiotensin system, to modify exercise capacity through actions on diastolic dysfunction, are the next step.
· Grewal J, McCully RB, Kane GC, et al. Left ventricular function and exercise capacity. JAMA 2009; 301:286-294