Abstract 17411: The Relationships Between QRS Duration and Morphology, Cardiac Structure and Function, and Incident Heart Failure in the Atherosclerosis Risk In Communities Study
Introduction: Prolonged QRS duration may be a marker of left ventricular (LV) dyssynchrony, remodeling, and increased risk for heart failure (HF).
Hypothesis: QRS duration ≥ 120 msec is associated with an increased risk of HF independent of LV structure and function.
Methods: The relationships between QRS duration, LV structure and function, and incident HF were evaluated in 1,868 middle-aged African-Americans without prevalent HF from the Jackson, MS cohort of the ARIC study who underwent echocardiography between 1993-1995. QRS duration was categorized as <100, 100-119, and ≥120 msec, with QRS ≥120 ms further characterized as LBBB, RBBB, or intraventricular conduction delay (IVCD) morphology. Incident HF was defined as a hospitalization or death with an ICD code of 428 or I50. The risk of HF was assessed across the spectrum of QRS duration using Cox proportional hazards models.
Results: QRS ≥120 ms was identified in 5.1% of participants. Those with QRS ≥ 120 ms were older, more commonly male, hypertensive, and obese. Increased LV wall thickness, size, and mass were significantly associated with increasing QRS duration, while LV ejection fraction was not. Over a median follow up of 14.9 years there were 293 (15.7%) incident HF events and those with QRS ≥ 120 ms developed HF at the highest rate (Fig A). In multivariate Cox models, including adjustment for age, gender, BMI, hypertension, systolic BP, diabetes, smoking, heart rate, ECG LVH, prevalent CHD, MI as a time varying covariate, and LV size, mass, and EF, there was a non-significant trend toward an increased risk of HF (HR 1.40; 95%CI 0.90-2.16) with a QRS ≥ 120 ms, as compared to QRS < 100 ms. However, among those with QRS ≥ 120 ms, only LBBB morphology was significantly associated with incident HF (HR 2.99, 95%CI 1.54-5.78), while RBBB and IVCD were not (Fig B).
Conclusion: Among middle aged African-Americans, LBBB, but not RBBB or IVCD, was associated with an increased risk of HF independent of cardiac structure and function.
- © 2013 by American Heart Association, Inc.