Prognostic value of frontal QRS-T angle in patients without clinical evidence of cardiovascular disease (from the Multi-Ethnic Study of Atherosclerosis).
Abnormal frontal QRS-T angle on a 12-lead electrocardiogram is associated with incident coronary heart disease and total mortality in a biracial cohort, but there have been no studies to date examining QRS-T angle's prognostic value across multiple ethnicities. We studied 6,814 participants (52.7% women, mean age 62 years) from Multi-Ethnic Study of Atherosclerosis, a multiethnic cohort aged 45 to 84 years free of clinical cardiovascular disease (CVD) at enrollment. Baseline examination included measurement of traditional risk factors and 12-lead electrocardiograms. Frontal QRS-T axis was defined as normal (less than seventy-fifth percentile), borderline (seventy-fifth to ninety-fifth percentile), or abnormal (ninety-fifth percentile or more), and participants were followed for the composite end point of incident CVD events: cardiovascular death, myocardial infarction, angina pectoris, or heart failure. After 7.6 years of follow-up, there were 444 total events. Borderline (HR [hazard ratio] 1.37, 95% confidence interval [CI] 1.10 to 1.70) and abnormal QRS-T angles (HR 2.2, 95% CI 1.63 to 2.97) were associated with incident CVD events in multivariate-adjusted models. However, after adjusting for T-wave abnormalities, there was no statistically significant association of either borderline (HR 1.12, 95% CI 0.90 to 1.41) or abnormal (HR 1.31, 95% CI 0.93 to 1.84) QRS-T angle with incident CVD events. Abnormal frontal QRS-T angle predicts incident CVD events in a multiethnic population, and this increased risk is primarily mediated through T-wave abnormalities. QRS-T angle provides an easily interpretable continuous marker of abnormal ventricular repolarization that can aid the everyday clinician in risk prediction.
Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
Joseph A
JA
Walsh
Elsayed Z
EZ
Soliman
Leonard
L
Ilkhanoff
Hongyan
H
Ning
Kiang
K
Liu
Saman
S
Nazarian
Donald M
DM
Lloyd-Jones
D000368:Aged; D000369:Aged, 80 and over; D058070:Asymptomatic Diseases / Q000453:epidemiology; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000208:ethnology* / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D018570:Risk Assessment; D014481:United States / Q000453:epidemiology