The effect of treatment with bisoprolol-first versus enalapril-first on cardiac structure and function in heart failure

Background: In CIBIS III, initiating chronic heart failure (CHF) treatment with bisoprolol (target dose 10 mg q.d.) followed by combination therapy with enalapril (target dose 10 mg b.i.d.), compared to the opposite order, showed similar effects on survival and hospitalization. By echocardiography, we evaluated the effects of these treatment strategies on cardiac structure and function. Methods: In a single-centre substudy, we compared the impact on left ventricular (LV) dimensions and ejection fraction (EF) of treatment with bisoprolol-first (n = 21) and enalapril-first (n = 19) in 40 beta-blocker and angiotensin-converting-enzyme-inhibitor naive patients, with stable, mild or moderate CHF (NYHA II-III) and LVEF <= 35%. Echocardiography was performed at baseline, after the 6-month monotherapy phase and after 12 months, i.e. after 6 months combination therapy. Results: Baseline characteristics were similar across treatment groups. After 6 months LVEF increased by 5.1 +/- 4.0 EF-% (P<0.0001) with Bisoprolol and 4.0 +/- 4.0 EF-% (P = 0.0005), with enalapril (between-group P = 0.47). LV end-diastolic volume (LVEDV) decreased by 8.1 +/- 4.7 ml (P<0.0001) with bisoprolol and by 4.6 +/- 8.2 ml (P = 0.03) with enalapril (between-group P = 0.16). Mean wall thickness (WT) decreased by 0.31 +/- 0.43 mm (P = 0.004) with bisoprolol and by 0.18 +/- 0.48 mm (P = 0.11) with enalapril (between-group P = 0.29). From baseline to 12 months, LVEF increased by 7.5 +/- 4.0 EF-% (P<0.0001) in Bisoprolol first group and 6.0 +/- 4.6 EF-% (P<0.0001), in the enalapril first group (between-group P = 0.31). LVEDV decreased by 12.9 +/- 6.3 ml (P