Cumulative effect of complete left bundle-branch block and chronic atrial fibrillation on 1-year mortality and hospitalization in patients with congestive heart failure. A report from the Italian network on congestive heart failure (in-CHF database).

BACKGROUND: Many clinical variables have been proposed as prognostic factors in patients with congestive heart failure. Among these, complete left bundle-branch block and atrial fibrillation are known to impair significantly left ventricular performance in patients with congestive heart failure. However, their combined effect on mortality has been poorly investigated. The aim of this study was to determine whether left bundle-branch block associated with atrial fibrillation had an independent, cumulative effect on mortality for congestive heart failure.

METHODS AND RESULTS: We analysed the Italian Network on congestive heart failure (IN-CHF) Registry that was established by the Italian Association of Hospital Cardiologists in 1995. One-year follow-up data were available for 5517 patients. Complete left bundle-branch block and atrial fibrillation were associated in 185 (3.3%) patients. In this population the cause of congestive heart failure was dilated cardiomyopathy (38.4%), ischaemic heart disease (35.1%), hypertensive heart disease (17.3%), and other aetiologies (9.2%). This combination of electrical defects was associated with an increased 1-year mortality from any cause (hazard ratio, HR: 1.88; 95% CI 1.37-2.57) and sudden death (HR: 1.89; 95% CI 1.17-3.03) and 1-year hospitalization rate (HR: 1.83; 95% CI 1.26-2.67).

CONCLUSIONS: In patients with congestive heart failure, the contemporary presence of left bundle-branch block and atrial fibrillation was associated with a significant increase in mortality. This synergistic effect remained significant after adjusting for clinical variables usually associated with advanced heart failure. We can conclude that this combination of electrical disturbances identifies a congestive heart failure specific population with a high risk of mortality.