Electrocardiographic QRS duration at rest is associated with
sudden cardiac death and death from
coronary heart disease in the general population. However, its relation to cardiovascular events in American Indians, a population with persistently high
cardiovascular disease mortality, is unknown. The relation of QRS duration to incident
cardiovascular disease during 17.2 years of follow-up was assessed in 1,851 male and female Strong Heart Study participants aged 45 to 74 years without known
cardiovascular disease at baseline. Cox regression with robust standard error estimates was used to determine the association between quintiles of QRS duration and incident
cardiovascular disease in gender-stratified analyses, adjusted for age, systolic blood pressure,
hypertension,
antihypertensive medication use, body mass index, current smoking, diabetes, total
cholesterol,
high-density lipoprotein cholesterol, and
albuminuria. In women only, QRS duration in the highest quintile (≥105 ms) conferred significantly higher risk of
cardiovascular disease than QRS duration in the lowest quintile (64 to 84 ms) (hazard ratio 1.6, 95% CI 1.1 to 2.4) likely because of higher risks of
coronary heart disease (hazard ratio 1.8, 95% CI 1.1 to 3.1) and
myocardial infarction (hazard ratio 2.1, 95% CI 1.0 to 4.7). Furthermore, when added to the Strong Heart Study
Coronary Heart Disease Risk Calculator, QRS duration significantly improved prediction of future
coronary heart disease events in women (Net Reclassification Index 0.17, 95% CI 0.06 to 0.47). In conclusion, QRS duration is an independent predictor of
cardiovascular disease in women in the Strong Heart Study cohort and may have value in estimating risk in populations with similar risk profiles and a high lifetime incidence of
cardiovascular disease.