Effects of left ventricular peak filling rate on exercise capacity 3 to 6 weeks after acute myocardial infarction.

STUDY OBJECTIVES To investigate the importance of early left ventricular (LV) diastolic filling on maintenance of exercise performance, we examined peak filling rate and its relation to exercise capacity during upright bicycle exercise in patients with recent myocardial infarction. DESIGN Retrospective analysis of data of cardiopulmonary exercise testing characteristics in patients with recent myocardial infarction. SETTING Coronary care unit in a university hospital. PATIENTS Fifty-one patients 3 to 6 weeks after acute myocardial infarction. INTERVENTIONS Upright bicycle exercise using a symptom-limited graded exercise protocol. MEASUREMENTS AND RESULTS Peak filling rate increased significantly from 1.55 +/- 0.52 at rest to 3.43 +/- 1.1 end-diastolic volume per second at peak exercise. Despite no significant relation between peak filling rate at rest and peak oxygen consumption, peak filling rate at peak exercise correlated significantly with peak oxygen consumption (r = 0.50; p < 0.002), stroke volume (r = 0.51; p < 0.002), and cardiac output (r = 0.56; p < 0.002) at peak exercise. Although both end-systolic and end-diastolic volumes increased from rest to peak exercise, the increases in end-systolic volume correlated inversely with the changes in peak filling rate during exercise (r = -0.45; p < 0.02), but the increases in end-diastolic volume did not. CONCLUSIONS During maximal upright bicycle exercise, exercise capacity and exercise hemodynamic responses were mainly dependent on early LV diastolic filling, and preserved LV systolic contraction, resulting in a cardiac suction effect following early diastole, seemed to have an important role in the enhancement of early LV diastolic filling in patients with recent myocardial infarction.