Abstract 14697: Ventricular Conduction and Long-term Outcomes in African Americans: Insights from the Jackson Heart Study
Background: Prolonged QRS duration has been associated with adverse outcomes in mostly white populations, but its clinical significance is not well established in other races.
Hypothesis: QRS prolongation is associated with increased mortality in African Americans.
Methods: We analyzed data from 5,146 African Americans in the Jackson Heart Study stratified by QRS duration measured on baseline 12-lead ECG. QRS prolongation was defined as QRS≥100 msec, and divided into mild (100-119 msec), moderate (120-149 msec) and severe (≥150 msec) conduction delay. We assessed the association between QRS duration and all-cause mortality using Cox proportional hazards models. We also identified factors associated with the development of QRS prolongation in patients with normal QRS at baseline using modified Poisson regression.
Results: At baseline, 30% (n=1,528) of participants had a prolonged QRS (n=1,360 mild, n=88 moderate and n=80 severe). The cumulative incidence of death within 8 years among those with any QRS prolongation was 12.6% (95% CI: 11.0-14.4) vs. 7.1% (95% CI: 6.3-8.0) without prolongation. The Figure presents the cumulative incidence of death by QRS duration. Following adjustment for baseline characteristics, any QRS prolongation was associated with increased mortality compared with no prolongation (HR 1.27, 95% CI: 1.03-1.56; p=0.02). Severe delay was associated with a 57% increase in mortality (95% CI: 1.01-2.45; p=0.047). There was a linear relationship between QRS duration and mortality (HR per 10 msec increase = 1.06, 95% CI: 1.01-1.12). Older age, male sex, prior MI, lower ejection fraction, left ventricular hypertrophy and dilatation were associated with the development of QRS prolongation.
Conclusion: QRS prolongation in African Americans is associated with increased mortality. Factors associated with developing QRS prolongation among African Americans include age, male sex, prior MI, and left ventricular structural abnormalities.
Author Disclosures: R.J. Mentz: Research Grant; Significant; BMS, AstraZeneca, GSK, Novartis, Gilead, Otsuka. M.A. Greiner: None. A.D. DeVore: Other Research Support; Modest; AHA, Novartis, Thoratec. S.M. Dunlay: None. G. Choudhary: None. P. Khazanie: None. T. Ahmad: Research Grant; Modest; Thoratec, Daland Clinical Research Fellowship. T. Randolph: None. Z.J. Eapen: Honoraria; Modest; Janssen. Consultant/Advisory Board; Modest; Cytokinetics, Novartis. E.C. O’Brien: None. K.L. Thomas: Research Grant; Significant; Boston scientific. Consultant/Advisory Board; Modest; Boston scientific. L.H. Curtis: None. A.F. Hernandez: Research Grant; Significant; Janssen, Novartis, BMS, GSK. Honoraria; Modest; Amgen, Janssen, BMS, Novartis.
- © 2014 by American Heart Association, Inc.