[Clinical trial of the month. The CIBIS-II study].

CIBIS-II was a multicentre bouble-blind randomized placebo-controlled trial which enrolled 2,647 class III-IV heart failure patients, with a left ventricular ejection fraction < or = 35%, receiving standard therapy with a diuretic and ACEI and randomly assigned to placebo (n = 1,320) or to bisoprolol (n = 1,327) 1.25 mg/day, progressively increased to a maximum of 10 mg/day. Mean follow-up was 1.3 years. The study was stopped early because the 2nd interim analysis showed a significant mortality benefit in the treated group. All cause mortality was significantly lower in the bisoprolol group (156 [11.8%] vs 228 [17.3%]; p < 0.0001). Sudden deaths were fewer among patients on bisoprolol and treatment effects were independent on severity and aetiology of heart failure.