[The effects of aerobic exercise on cardiac output during exercise in patients with chronic heart failure].

OBJECTIVE: To observe the effects of aerobic exercise on cardiac output during exercise in patients with chronic heart failure (CHF).

METHODS: A total of 50 CHF patients (echocardiography measured left ventricular ejection fraction < 0.49) were enrolled in the study and randomly divided into aerobic exercise group (n = 25) and control group (n = 25). Cardiopulmonary exercise testing (CPET) was performed. Patients of aerobic exercise group underwent aerobic exercise according to aerobic exercise prescription and exercise intensity is decided by anaerobic threshold before 10 J/s (1 minute before) of the oxygen consumption. After 6 supervised aerobic exercise training sessions in the hospital, patients were asked to perform the home-based aerobic exercise training. Patients in control group were required to maintain daily physical activities. CPET were reviewed 3 months later.

RESULTS: Cardiac output (CO), peak CO, peak cardiac power output (peak CPO), resting heart rate (HR), heart rate at AT (HRAT), HR peak, resting mean arterial pressure (MAP), peak MAP at baseline were similar between aerobic exercise group and control [(4.2 ± 2.0) L/min vs. (3.3 ± 1.0) L/min, (6.2 ± 2.7) L/min vs. (5.2 ± 1.8) L/min, (1.8 ± 2.9) L/min vs. (2.0 ± 1.8) L/min, (1.3 ± 0.5) J/s vs. (1.2 ± 0.5) J/s, (76.8 ± 13.5) beats/min vs. (73.4 ± 11.9) beats/min, (91.5 ± 11.3) beats/min vs. (92.6 ± 12.4) beats/min, (106.0 ± 12.9) beats/min vs. (108.3 ± 17.4) beats/min, (80.8 ± 9.9) mm Hg (1 mm Hg = 0.133 kPa) vs. (87.6 ± 13.3) mm Hg, (98.8 ± 12.4) mm Hg vs. (102.7 ± 13.9) mm Hg, all P > 0.05]. Compared to baseline, CO, peak CO, peak CPO, HR, HRAT, HR peak, MAP, peak MAP after 3 months were similar between aerobic exercise group and control (all P > 0.05). The differences between baseline and 3 months later expressed as ΔCO, Δpeak CO, Δpeak CPO, ΔHR, ΔHRAT, ΔHR peak, ΔMAP, Δpeak MAP were also similar between aerobic exercise group and control group [(-0.7 ± 2.4) L/min vs. (0.7 ± 2.0) L/min, (1.1 ± 2.6) L/min vs. (1.4 ± 2.1) L/min, (0.1 ± 3.7) L/min vs. (-0.2 ± 2.5) L/min, (0.2 ± 1.0) J/s vs. (0.2 ± 0.5) J/s, (-0.4 ± 7.6) beats/min vs. (1.9 ± 9.9) beats/min, (3.4 ± 11.3) beats/min vs. (-2.8 ± 7.6) beats/min, (8.9 ± 14.5) beats/min vs. (3.7 ± 14.4) beats/min, (1.5 ± 12.8) mm Hg vs. (-1.3 ± 11.1) mm Hg, (6.4 ± 18.9) mm Hg vs. (1.3 ± 12.3) mm Hg, all P > 0.05].

CONCLUSION: Three months aerobic exercise training did not improve cardiac output and related parameters during exercise in this cohort patients with CHF.