Electrocardiographic intervals associated with incident atrial fibrillation: Dissecting the QT interval

• Type of Material: Article
• Authors: Jason D. Roberts, Western University; Elsayed Z. Soliman, Wake Forest University; Alvaro Alonso, Emory University; Eric Vittinghoff, University of California San Francisco; Lin Y. Chen, University of Minnesota; Laura Loehr, University of North Carolina; Gregory M. Marcus, University of California San Francisco
• Language: English
• Date: 2017-05-01
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2017 Heart Rhythm Society
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.hrthm.2017.02.005
• Title of Journal or Parent Work: Heart Rhythm
• ISSN: 1547-5271
• Volume: 14
• Issue: 5
• Start Page: 654
• End Page: 660
• Grant/Funding Information: JDR is supported by a Canadian Stroke Prevention Intervention Network (C-SPIN) Bayer Junior Faculty Fellowship Award and a Heart and Stroke Foundation of Ontario Emerging Research Leaders Initiative Award.; AA is supported by American Heart Association grant 16EIA26410001.; The Atherosclerosis Risk in Communities Study is carried out as a collaborative study supported by National Heart, Lung, and Blood Institute contracts (HHSN268201100005C, HHSN268201100006C, HHSN268201100007C, HHSN268201100008C, HHSN268201100009C, HHSN268201100010C, HHSN268201100011C, and HHSN268201100012C).
• Keywords: ECG; Atrial fibrillation; QT interval; RHYTHM CONTROL; DELAYED AFTERDEPOLARIZATIONS; RISK; Life Sciences & Biomedicine; HEART-FAILURE; ABLATION; Cardiovascular System & Cardiology; Arrhythmia; Science & Technology; IMPACT; Electrocardiography; Cardiac & Cardiovascular Systems; Epidemiology; PREVALENCE
• Research Categories: Biology, Biostatistics; Health Sciences, Epidemiology

Abstract

Background Prolongation of the QT interval has been associated with an increased risk of developing atrial fibrillation (AF), but the responsible mechanism remains unknown. Objectives The aims of this study were to subdivide the QT interval into its components and identify the resultant electrocardiographic interval(s) responsible for the association with AF. Methods Predefined QT-interval components were assessed for association with incident AF in the Atherosclerosis Risk in Communities study using Cox proportional hazards models. Hazard ratios (HRs) were calculated per 1-SD increase in each component. Among QT-interval components exhibiting significant associations, additional analyses evaluating long extremes, defined as greater than the 95th percentile, were performed. Results Of the 14,625 individuals, 1505 (10.3%) were diagnosed with incident AF during a mean follow-up period of 17.6 years. After multivariable adjustment, QT-interval components involved in repolarization, but not depolarization, exhibited significant associations with incident AF, including a longer ST segment (HR 1.27; 95% confidence interval [CI] 1.14–1.41; P <.001) and a prolonged T-wave onset to T-wave peak (T-onset to T-peak) (HR 1.13; 95% CI 1.07–1.20; P <.001). Marked prolongation of the ST segment (HR 1.31; 95% CI 1.04–1.64; P =.022) and T-onset to T-peak (HR 1.36; 95% CI 1.09–1.69; P =.006) was also associated with an increased risk of incident AF. Conclusion The association between a prolonged QT interval and incident AF is primarily explained by components involved in ventricular repolarization: prolongation of the ST segment and T-onset to T-peak. These observations suggest that prolongation of phases 2 and 3 of the cardiac action potential drives the association between the QT interval and AF risk.