CIRCULATORY STATUS AND RESPONSE TO CARDIAC REHABILITATION IN PATIENTSWITH HEART-FAILURE

Background We recently reported that some patients with heart failure and exercise intolerance exhibit severe hemodynamic dysfunction during exercise, whereas others have normal cardiac output responses to exer cise. We postulated that, patients with preserved cardiac output respo nses to exercise are limited by deconditioning and would respond to ex ercise training: whereas patients with reduced cardiac output response s are limited by skeletal muscle underperfusion and would not improve with exercise training. The present study was undertaken to test this hypothesis. Methods and Results Thirty-two patients with heart failure were studied. Hemodynamic response to maximal treadmill exercise was measured; then patients were enrolled in a standard 3-month cardiac re habilitation program. Peak exercise VO2, lactate threshold, and qualit y-of-life questionnaires were assessed at 1, 2, and 3 months. Twenty-o ne patients had normal cardiac output responses to exercise. All 21 pa tients participated in the rehabilitation program without difficulty, and 9 (43%) responded to rehabilitation, defined as a >10% increase in both peak exercise VO2 and the anaerobic threshold. Of the 11 patient s with reduced cardiac output responses to exercise, 3 discontinued re habilitation because of severe exhaustion, and only 1 qualified as a r esponder (9%; P<.04 versus preserved cardiac output). Conclusions Pati ents with heart failure and normal cardiac output responses to exercis e frequently improve with exercise training. Patients with severe hemo dynamic dysfunction during exercise usually do not improve with traini ng, which suggests that they are limited primarily by circulatory fact ors.