Scientific Publications

QT Interval and Long-Term Mortality Risk in the Framingham Heart Study.

Publication TypeJournal Article
AuthorsNoseworthy, PA, Peloso GM, Hwang SJ, Larson MG, Levy D., O'Donnell CJ, and Newton-Cheh C.
AbstractBackground: The association between QT interval and mortality has been demonstrated in large, prospective population-based studies, but the strength of the association varies considerably based on the method of heart rate correction. We examined the QT-mortality relationship in the Framingham Heart Study (FHS). Methods: Participants in the first (original cohort, n = 2,365) and second generation (offspring cohort, n = 4,530) cohorts were included in this study with a mean follow up of 27.5 years. QT interval measurements were obtained manually using a reproducible digital caliper technique. Results: Using Cox proportional hazards regression adjusting for age and sex, a 20 millisecond increase in QTc (using Bazett's correction; QT/RR(1/2) interval) was associated with a modest increase in risk of all-cause mortality (HR 1.14, 95% CI 1.10-1.18, P < 0.0001), coronary heart disease (CHD) mortality (HR 1.15, 95% CI 1.05-1.26, P = 0.003), and sudden cardiac death (SCD, HR 1.19, 95% CI 1.03-1.37, P = 0.02). However, adjustment for heart rate using RR interval in linear regression attenuated this association. The association of QT interval with all-cause mortality persisted after adjustment for cardiovascular risk factors, but associations with CHD mortality and SCD were no longer significant. Conclusion: In FHS, there is evidence of a graded relation between QTc and all-cause mortality, CHD death, and SCD; however, this association is attenuated by adjustment for RR interval. These data confirm that using Bazett's heart rate correction, QTc, overestimates the association with mortality. An association with all-cause mortality persists despite a more complete adjustment for heart rate and known cardiovascular risk factors.
Year of Publication2012
JournalAnnals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc
Date Published (YYYY/MM/DD)2012/10/01
ISSN Number1082-720X