Left ventricular response to submaximal and maximal exercise in asymptomatic aortic regurgitation

In patients with chronic aortic regurgitation the quantitative changes in loading conditions and left ventricular performance from rest to submaximal exercise have not been related to the magnitude of change observed from rest to maximal exercise. Changes in end-diastolic volume index, as a measure of preload, and measures of contractile performance (ejection fraction and the systolic blood pressure/end-systolic volume index ratio) were assessed at rest, submaximal and maximal supine bicycle exercise using radionuclide angiography in 74 patients with chronic moderate to severe aortic regurgitation. With exercise, end-diastolic volume index decreased in a stepwise manner from 166 +/- 47 to 152 +/- 41 to 143 +/- 41 ml/m2 at rest, submaximal and maximal exercise, respectively. For the entire group, these changes were not associated with a significant change in ejection fraction but were associated with stepwise increases in systolic blood pressure to end-systolic volume index ratio. However, when patients were divided into 3 subgroups based on an increase (group I), minimal change (group II) or a decrease (group III) in ejection fraction from rest to maximal exercise, stepwise increases in systolic blood pressure to end-systolic volume index were again observed in groups I and II but not in group III. These changes were significantly greater in group I than in group II at submaximal and maximal exercise levels. Differences in ejection fraction response and end-diastolic and end-systolic volumes with exercise in the 3 groups were evident at the submaximal exercise level.(ABSTRACT TRUNCATED AT 250 WORDS)