Abstract 11317: Does the Degree of QRS Prolongation in Bundle Branch Blocks Modify the Risk of Incident Heart Failure? The Atherosclerosis Risk in Communities Study
Background: Left bundle branch block (LBBB) is associated with increased risk of heart failure (HF). Whether a more pronounced widening of QRS duration in LBBB and in other BBBs modifies the risk of HF is unknown.
Methods and Results: This analysis included 14,522 participants from the Atherosclerosis Risk in Communities (ARIC) study (mean age 54 years, 55% women, and 26% blacks) free of HF at baseline. During an average 18 years follow-up, 1,772 incident hospitalized HF, defined by any listing of a HF hospital ICD code (428) or death certificate ICD code (428, I50), occurred. At baseline,377 participants had BBB, categorized as lone RBBB, LBBB, indetermined type BBB (IVCD), and RBBB with left anterior fascicular block (LAFB). Cox proportional hazard analysis was used to examine the association between different patterns of BBB with incident HF. Compared to QRS duration <100 ms, LBBB, IVCD, and RBBB &LAFB were associated with increased risk of HF (HR=2.9, 1.8, and 2.1, respectively), and so these categories were combined and labeled as pooled LBBB group. In multivariable adjustment models, incident HF risk was over 2-fold for the pooled LBBB group while it was not significant for lone RBBB. The group with QRS duration 100-119 ms had a modestly increased (1.2-fold) risk of incident HF. When the BBB groups were stratified by the level of QRS duration using 140 ms as a cut point, the risk of incident HF in pooled LBBB group was 1.8-fold for QRS duration range 120-139 ms and 3.1-fold for QRS duration ≥140 ms (Table). In all models, lone RBBB was not associated with incident HF.
Conclusions: Except for lone RBBB, all major BBBs are predictive of incident HF, and the risk is further increased when QRS duration is 140 ms or wider. These findings may help in selecting patients who could benefit from further diagnostic evaluation for therapeutic and preventive action.
- © 2013 by American Heart Association, Inc.