Dataset Information

The QT interval and risk of incident atrial fibrillation.

ABSTRACT: Abnormal atrial repolarization is important in the development of atrial fibrillation (AF), but no direct measurement is available in clinical medicine.To determine whether the QT interval, a marker of ventricular repolarization, could be used to predict incident AF.We examined a prolonged QT interval corrected by using the Framingham formula (QT(Fram)) as a predictor of incident AF in the Atherosclerosis Risk in Communities (ARIC) study. The Cardiovascular Health Study (CHS) and Health, Aging, and Body Composition (ABC) study were used for validation. Secondary predictors included QT duration as a continuous variable, a short QT interval, and QT intervals corrected by using other formulas.Among 14,538 ARIC study participants, a prolonged QT(Fram) predicted a roughly 2-fold increased risk of AF (hazard ratio [HR] 2.05; 95% confidence interval [CI] 1.42-2.96; P < .001). No substantive attenuation was observed after adjustment for age, race, sex, study center, body mass index, hypertension, diabetes, coronary disease, and heart failure. The findings were validated in Cardiovascular Health Study and Health, Aging, and Body Composition study and were similar across various QT correction methods. Also in the ARIC study, each 10-ms increase in QT(Fram) was associated with an increased unadjusted (HR 1.14; 95% CI 1.10-1.17; P < .001) and adjusted (HR 1.11; 95% CI 1.07-1.14; P < .001) risk of AF. Findings regarding a short QT interval were inconsistent across cohorts.A prolonged QT interval is associated with an increased risk of incident AF.

SUBMITTER: Mandyam MC

PROVIDER: S-EPMC3787974 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

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The QT interval and risk of incident atrial fibrillation.

Mandyam Mala C MC Soliman Elsayed Z EZ Alonso Alvaro A Dewland Thomas A TA Heckbert Susan R SR Vittinghoff Eric E Cummings Steven R SR Ellinor Patrick T PT Chaitman Bernard R BR Stocke Karen K Applegate William B WB Arking Dan E DE Butler Javed J Loehr Laura R LR Magnani Jared W JW Murphy Rachel A RA Satterfield Suzanne S Newman Anne B AB Marcus Gregory M GM

Heart rhythm 20130718 10

<h4>Background</h4>Abnormal atrial repolarization is important in the development of atrial fibrillation (AF), but no direct measurement is available in clinical medicine.<h4>Objective</h4>To determine whether the QT interval, a marker of ventricular repolarization, could be used to predict incident AF.<h4>Methods</h4>We examined a prolonged QT interval corrected by using the Framingham formula (QT(Fram)) as a predictor of incident AF in the Atherosclerosis Risk in Communities (ARIC) study. The ...[more]

PMID: 23872693

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Project description:BackgroundThe QT interval measures cardiac repolarization, and prolongation is associated with adverse cardiovascular outcomes and death. The exponential Bazett correction formula overestimates the QT interval during tachycardia.ObjectiveWe evaluated 4 formulas of QT interval correction in individuals with sinus tachycardia for the identification of coronary artery disease, heart failure, and mortality.MethodsThe Penn Atrial Fibrillation Free study is a large cohort study of patients without atrial fibrillation. The present study examined 6723 Penn Atrial Fibrillation Free study patients without a history of heart failure and with baseline sinus rate ≥100 beats/min. Medical records were queried for index clinical parameters, incident cardiovascular events, and all-cause mortality. The QT interval was corrected by using Bazett (QT/RR(0.5)), Fridericia (QT/RR(0.33)), Framingham [QT + 0.154 * (1000 - RR)], and Hodges (QT + 105 * (1/RR - 1)) formulas.ResultsIn 6723 patients with a median follow-up of 4.5 years (interquartile range 1.9-6.4 years), the annualized cardiovascular event rate was 2.3% and the annualized mortality rate was 2.2%. QT prolongation was diagnosed in 39% of the cohort using the Bazett formula, 6.2% using the Fridericia formula, 3.7% using the Framingham formula, and 8.7% using the Hodges formula. Only the Hodges formula was an independent risk marker for death across the range of QT values (highest tertile: hazard ratio 1.26; 95% confidence interval 1.03-1.55).ConclusionAlthough all correction formulas demonstrated an association between QTc values and cardiovascular events, only the Hodges formula identified one-third of individuals with tachycardia that are at higher risk of all-cause mortality. Furthermore, the Bazett correction formula overestimates the number of patients with a prolonged QT interval and was not associated with mortality. Future work may validate these findings and result in changes to automated algorithms for QT interval assessment.

Project description:OBJECTIVES:This study sought to identify modifiable risk factors and estimate the impact of risk factor modification on heart failure (HF) risk in women with new-onset atrial fibrillation (AF). BACKGROUND:Incident HF is the most common nonfatal event in patients with AF, although strategies for HF prevention are lacking. METHODS:We assessed 34,736 participants in the Women's Health Study who were free of prevalent cardiovascular disease at baseline. Cox models with time-varying assessment of risk factors after AF diagnosis were used to identify significant modifiable risk factors for incident HF. RESULTS:Over a median follow-up of 20.6 years, 1,495 women developed AF without prevalent HF. In multivariable models, new-onset AF was associated with an increased risk of HF (hazard ratio [HR]: 9.03; 95% confidence interval [CI]: 7.52 to 10.85). Once women with AF developed HF, all-cause (HR: 1.83; 95% CI: 1.37 to 2.45) and cardiovascular mortality (HR: 2.87; 95% CI: 1.70 to 4.85) increased. In time-updated, multivariable models accounting for changes in risk factors after AF diagnosis, systolic blood pressure >120 mm Hg, body mass index ?30 kg/m2, current tobacco use, and diabetes mellitus were each associated with incident HF. The combination of these 4 modifiable risk factors accounted for an estimated 62% (95% CI: 23% to 83%) of the population-attributable risk of HF. Compared with women with 3 or 4 risk factors, those who maintained or achieved optimal risk factor control had a progressive decreased risk of HF (HR for 2 risk factors: 0.60; 95% CI: 0.37 to 0.95; 1 risk factor: 0.40; 95% CI: 0.25 to 0.63; and 0 risk factors: 0.14; 95% CI: 0.07 to 0.29). CONCLUSIONS:In women with new-onset AF, modifiable risk factors including obesity, hypertension, smoking, and diabetes accounted for the majority of the population risk of HF. Optimal levels of modifiable risk factors were associated with decreased HF risk. Prospective assessment of risk factor modification at the time of AF diagnosis may warrant future investigation.

Dataset Information

The QT interval and risk of incident atrial fibrillation.

Publications

The QT interval and risk of incident atrial fibrillation.

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