Effects of Exercise Training in Patients With Chronic Heart Failure and Advanced Left Ventricular Systolic Dysfunction Receiving .BETA.-Blockers

Abstract

It remains unclear whether patients with chronic heart failure (CHF) and advanced left ventricular (LV) dysfunction on β-blocker therapy benefit from exercise training (ET). We studied 45 CHF patients with advanced LV dysfunction [ejection fraction (LVEF) < 25%] and impaired exercise tolerance [normalized peak oxygen uptake (PVO₂) < 70%] receiving a β-blocker: 33 patients participated in a cardiac rehabilitation program with ET (ET group) and 12 did not (inactive control group). Exercise capacity, LV dimension and plasma B-type natriuretic peptide (BNP) were assessed before and after a 3-month study period. At baseline, both groups had markedly reduced LVEF (ET group 18 ± 4% vs. Control group 18 ± 5%, NS) and impaired exercise capacity (normalized PVO₂ 51 ± 10% vs. 55 ± 9%, NS). Although one patient in the ET group withdrew from the program due to worsening CHF, no serious cardiac events occurred during the ET sessions. After 3 months, the ET group (n = 24) had significantly improved PVO₂ by 16 ± 15% (1,005 ± 295 to 1,167 ± 397ml/min, P < 0.001), while the PVO₂ of the control group was unchanged. LV end-diastolic dimension decreased in both groups to a similar extent, but plasma BNP was significantly decreased only in the ET group (432 to 214 pg/ml, P < 0.05). The data indicate that in CHF patients with advanced LV dysfunction on β-blocker therapy, ET successfully improves exercise capacity and BNP without adversely affecting LV remodeling or causing serious cardiac complications.