Relation between left ventricular diastolic function and exercise tolerance in patients with left ventricular dysfunction.

Previous studies show no correlation between resting systolic left ventricular performance assessed as the ejection fraction and exercise tolerance. This study examined the relation between left ventricular diastolic performance and exercise tolerance in 63 patients with left ventricular dysfunction (ejection fraction less than 50%) due to known or suspected coronary artery disease. The 51 men and 12 women, aged 54 +/- 8 years (mean +/- standard deviation), underwent symptom-limited upright exercise testing on a bicycle ergometer. The exercise end-points were angina (n:5), dyspnea (n:16), and fatigue (n:42). The patients were divided into three groups: group 1 (n:28) with normal exercise tolerance (9.5 +/- 2.4 minutes), group 2 (n:18) with mild exercise intolerance (5.8 +/- 0.5 minutes), and group 3 (n:17) had severe exercise intolerance (3.7 +/- 0.9 minutes). The three groups did not differ in age, ejection fraction, end-diastolic volume, exercise end-point, exercise heart rate, and left ventricular peak filling rate at rest. The exercise peak filling rate was, however, significantly higher in group 1 (p = 0.03). Stepwise multivariate discriminant analysis of important variables identified the exercise peak filling rate as the only predictor of exercise tolerance (F = 6.0). Thus, variation in exercise peak filling rate may in part explain the variability of exercise tolerance in patients with left ventricular dysfunction; patients with preserved exercise capacity have higher exercise peak filling rate than those with exercise intolerance.