O'Neal Wesley T, Efird Jimmy T, Kamel Hooman, Nazarian Saman, Alonso Alvaro, Heckbert Susan R, Longstreth W T, Soliman Elsayed Z
Department of Internal Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, USA,
Clin Res Cardiol. 2015 Sep;104(9):743-50. doi: 10.1007/s00392-015-0838-z. Epub 2015 Mar 10.
Prolongation of the QT interval is associated with an increased risk of atrial fibrillation (AF) and stroke.
The purpose of this analysis was to determine if AF explains the association between prolonged QT and stroke.
A total of 6305 participants (mean age 62 ± 10 years; 54% women; 38% whites; 27% blacks; 23% Hispanics; 12% Chinese-Americans) from the Multi-Ethnic Study of Atherosclerosis (MESA) were included in this analysis. A linear scale was used to compute heart rate-adjusted QT (QT(a)). Prolonged QT(a) was defined as ≥ 460 ms in women and ≥ 450 ms in men. Incident AF cases were identified using hospital discharge records and Medicare claims data. Vascular neurologists adjudicated stroke events by medical record review. Cox regression was used to examine the association between prolonged QT(a) and stroke with and without AF.
A total of 216 (3.4%) of study participants had prolonged QT(a). Over a median follow-up of 8.5 years, 280 (4.4%) participants developed AF and 128 (2.0%) participants developed stroke. In a multivariable Cox regression analysis adjusted for socio-demographics, cardiovascular risk factors, and potential confounders, prolonged QT(a) was associated with an increased risk of AF (HR = 1.7, 95% CI 1.1, 2.6) and stroke (HR = 2.3, 95% CI 1.3, 4.1). When AF was included as a time-dependent covariate, the association between prolonged QT(a) and stroke was not substantively altered (HR = 2.4, 95% CI 1.3, 4.3).
The increased risk of stroke in those with prolonged QT potentially is not explained by documented AF. Further research is needed to determine if subclinical AF explains the association between the QT interval and stroke.
QT间期延长与心房颤动（AF）和中风风险增加相关。
本分析的目的是确定AF是否能解释QT延长与中风之间的关联。
多民族动脉粥样硬化研究（MESA）中的6305名参与者（平均年龄62±10岁；54%为女性；38%为白人；27%为黑人；23%为西班牙裔；12%为华裔美国人）纳入本分析。使用线性量表计算心率校正QT（QT(a)）。QT(a)延长定义为女性≥460毫秒，男性≥450毫秒。通过医院出院记录和医疗保险理赔数据确定新发AF病例。血管神经科医生通过病历审查判定中风事件。采用Cox回归分析有或无AF时QT(a)延长与中风之间的关联。
共有216名（3.4%）研究参与者QT(a)延长。在中位随访8.5年期间，280名（4.4%）参与者发生AF，128名（2.0%）参与者发生中风。在对社会人口统计学、心血管危险因素和潜在混杂因素进行校正的多变量Cox回归分析中，QT(a)延长与AF风险增加（HR = 1.7，95%CI 1.1，2.6）和中风风险增加（HR = 2.3，95%CI 1.3，4.1）相关。当将AF作为时间依赖性协变量纳入时，QT(a)延长与中风之间的关联没有实质性改变（HR = 2.4，95%CI 1.3，4.3）。
QT延长者中风风险增加可能无法用已记录的AF来解释。需要进一步研究以确定亚临床AF是否能解释QT间期与中风之间的关联。
