Ventricular conduction and long-term heart failure outcomes and mortality in African Americans: insights from the Jackson Heart Study
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Robert J Mentz1, Melissa A Greiner2, Adam D DeVore2
1From the Department of Medicine, Division of Cardiology, Duke University School of Medicine (R.J.M., A.D.D., T.A., P.K., T.C.R., Z.J.E., E.C.O'B., K.L.T., A.F.H.), and Duke Clinical Research Institute (R.J.M., M.A.G., A.D.D., T.C.R., Z.J.E., E.C.O'B., K.L.T., L.H.C., A.F.H.), Durham, NC; Department of Medicine, Mayo Clinic, Rochester, MN (S.M.D.); Vascular Research Laboratory, Providence VA Medical Center and Department of Medicine, Warren Alpert Medical School of Brown University, Providence, RI (G.C.); and Center of Biostatistics and Bioinformatics, University of Mississippi Medical Center, Jackson, MS (M.E.G.). robert.mentz@duke.edu.
Insights
QRS prolongation, a measure of heart
Area of Science:
- Cardiology
- Public Health
- Epidemiology
Background:
- QRS prolongation is linked to adverse outcomes in White populations.
- Its clinical significance in African Americans is not well-established.
- This study investigates QRS duration and mortality in African Americans.
Purpose of the Study:
- To investigate the association between QRS duration and mortality in African Americans.
- To identify factors associated with QRS prolongation in this population.
Main Methods:
- Analysis of 5146 African Americans from the Jackson Heart Study.
- Stratification by QRS duration on baseline 12-lead ECG (QRS prolongation defined as ≥100 ms).
- Cox proportional hazards models for mortality and heart failure hospitalization risk.
Main Results:
- 30% of participants had baseline QRS prolongation.
- QRS prolongation was associated with increased all-cause mortality (HR, 1.27; P=0.02).
- A linear relationship existed between QRS duration and mortality.
- Factors associated with QRS prolongation included older age, male sex, prior MI, lower EF, LVH, and LVD.
Conclusions:
- QRS prolongation in African Americans is linked to higher mortality and heart failure hospitalization.
- Age, male sex, prior myocardial infarction, and left ventricular abnormalities are associated with developing QRS prolongation.
Background:
QRS prolongation is associated with adverse outcomes in mostly white populations, but its clinical significance is not well established for other groups. We investigated the association between QRS duration and mortality in African Americans.
Methods And Results:
We analyzed data from 5146 African Americans in the Jackson Heart Study stratified by QRS duration on baseline 12-lead ECG. We defined QRS prolongation as QRS≥100 ms. We assessed the association between QRS duration and all-cause mortality using Cox proportional hazards models and reported the cumulative incidence of heart failure hospitalization. We identified factors associated with the development of QRS prolongation in patients with normal baseline QRS. At baseline, 30% (n=1528) of participants had QRS prolongation. The cumulative incidences of mortality and heart failure hospitalization were greater with versus without baseline QRS prolongation: 12.6% (95% confidence interval [CI], 11.0-14.4) versus 7.1% (95% CI, 6.3-8.0) and 8.2% (95% CI, 6.9-9.7) versus 4.4% (95% CI, 3.7-5.1), respectively. After risk adjustment, QRS prolongation was associated with increased mortality (hazard ratio, 1.27; 95% CI, 1.03-1.56; P=0.02). There was a linear relationship between QRS duration and mortality (hazard ratio per 10 ms increase, 1.06; 95% CI, 1.01-1.12). Older age, male sex, prior myocardial infarction, lower ejection fraction, left ventricular hypertrophy, and left ventricular dilatation were associated with the development of QRS prolongation.
Conclusions:
QRS prolongation in African Americans was associated with increased mortality and heart failure hospitalization. Factors associated with developing QRS prolongation included age, male sex, prior myocardial infarction, and left ventricular structural abnormalities.