The prevalence and incidence of left bundle branch block in ambulant patients with chronic heart failure

Background: Approximately one third of patients with chronic heart failure have left bundle branch block (LBBB) on their 12-lead ECG. Methods and results: 1418 consecutive patients (average (SD) age 70.5 (10.4) years; 74% male) first seen in a community heart failure clinic between December 2001 and June 2006 had a 12 lead electrocardiogram (ECG). 485 (34%) had a QRS duration >= 120 ins. Patients with a broad QRS were older (72.2 v 69.3 years), had worse left ventricular systolic function, were on a higher daily dose of diuretic and were more likely to be on amiodarone (14.4 v 7.1%). 12 lead ECG was available for 734 patients (52%) at 1 year follow up. The QRS interval increased from 115.1 ms at baseline to 117.6 (P < 0.0001). There were 52 incident cases of LBBB, an incidence of 10.9%. The only predictors of incident LBBB were QRS duration at baseline and amiodarone use at baseline. The proportion of patients with LBBB increased from 34.0% at baseline to 36.7%, 37.7% and 42.3% at 1, 2 and 3 years follow up, respectively. Baseline LBBB was associated with a worse outcome HR 1.25 (95% CI 1.01-1.55). New LBBB was an independent adverse prognostic feature (HR 2.09 (95% CI 1.17-3.73); P=0.013). Conclusions: The crude incidence of LBBB is 10.9% in the first year of follow up in an unselected population of ambulatory outpatients with chronic stable heart failure. Ongoing care of patients with chronic heart failure should include a regular 12 lead electrocardiogram. (c) 2008 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.