Heart rate and cardiac rhythm relationships with bisoprolol benefit in chronic heart failure in CIBISII trial

Background-beta -Blockade-induced benefit in heart failure (HF) could be re lated to baseline heart rate and treatment-induced heart rate reduction, bu t no such relationships have been demonstrated. Methods and Results-In CIBIS II, we studied the relationships between basel ine heart rate (BHR), heart rate changes at 2 months (HRC), nature of cardi ac rhythm (sinus rhythm or atrial fibrillation), and outcomes (mortality an d hospitalization for HF). Multivariate analysis of CIBIS II showed that in addition to beta -blocker treatment, BHR and HRC were both significantly r elated to survival and hospitalization for worsening HF, the lowest BHR and the greatest HRC being associated with best survival and reduction of hosp ital admissions. No interaction between the 3 variables was observed, meani ng that on one hand, HRC-related improvement in survival was similar at all levels of BHR, and on the other hand, bisoprolol-induced benefit over plac ebo for survival was observed to a similar extent at any level of both BHR and HRC. Bisoprolol reduced mortality in patients with sinus rhythm (relati ve risk 0.58, P<0.001) but not in patients with atrial fibrillation (relati ve risk 1.16, P=NS). A similar result was observed for cardiovascular morta lity and hospitalization for HF worsening. Conclusions-BHR and HRC are significantly related to prognosis in heart fai lure. <beta>-Blockade with bisoprolol further improves survival at any leve l of BHR and HRC and to a similar extent. The benefit of bisoprolol is ques tionable, however, in patients with atrial fibrillation.