BEAT-TO-BEAT EVALUATION OF CARDIAC-FUNCTION DURING RECOVERY FROM UPRIGHT BICYCLE EXERCISE IN PATIENTS WITH CORONARY-ARTERY DISEASE

The purpose of this study was to evaluate the time course of cardiac function during recovery from upright bicycle exercise in patients with coronary artery disease. Twelve patients with coronary artery disease performed a symptom-limited exercise test on a cycle ergometer. Left ventricular function was continuously monitored during exercise and recovery with a computerized cadmium telluride detector following the intravenous injection of technetium-labeled red blood cells. Although the end-diastolic volume (153.4 ± 76.1 ml) and end-systolic volume (100.5 ± 67.3 ml) at the end of exercise were significantly higher than the respective resting values, stroke volume (52.8 ± 16.1 ml) and ejection fraction (38.0 ± 12.2%) were not different from the respective resting values. The recovery of cardiac output was relatively slow compared with that of heart rate, because stroke volume rose sharply early in recovery. The rise in stroke volume was chiefly a result of a significant decrease in end-systolic volume between 1 and 4 minutes of recovery. These changes may result from an immediate afterload reduction coupled with a relatively slow decrease in sympathetic stimulation. The time course of cardiac function during recovery from exercise in cardiac patients is substantially different from that of normal subjects and may be a sensitive way to evaluate the peripheral vascular function and deteriorated cardiac function in cardiac patients. © 1990.