Akylbekova Ermeg L, Crow Richard S, Johnson William D, Buxbaum Sarah G, Njemanze Stephanie, Fox Ervin, Sarpong Daniel F, Taylor Herman A, Newton-Cheh Christopher
Jackson State University, Jackson Heart Study, Jackson, Miss, USA.
Circ Arrhythm Electrophysiol. 2009 Aug;2(4):427-32. doi: 10.1161/CIRCEP.109.858894. Epub 2009 May 27.
Electrocardiographic QT interval prolongation is a risk factor for sudden cardiac death and drug-induced arrhythmia. The clinical correlates and heritability of QT interval duration in blacks have not been well studied despite their higher risk for sudden cardiac death compared with non-Hispanic whites. We sought to investigate potential correlates of the QT interval and estimate its heritability in the Jackson Heart Study.
The Jackson Heart Study comprises a sample of blacks residing in Jackson, Miss, of whom 5302 individuals with data at the baseline examination were available for study. Jackson Heart Study participants on QT-altering medications, with bundle-branch block, paced rhythm, atrial fibrillation/flutter, or other arrhythmias were excluded, resulting in a sample of 4660 individuals eligible for analyses. The relation between QT and potential covariates was tested using multivariable stepwise linear regression. Heritability was estimated using Sequential Oligogenic Linkage Analysis Routine in a subset of 1297 Jackson Heart Study participants in 292 families; the remaining sample included unrelated individuals. In stepwise multivariable linear regression analysis, covariates significantly associated with QT interval duration included R-R interval, sex, QRS duration, age, serum potassium, hypertension, body mass index, coronary heart disease, diuretic use, and Sokolow-Lyon voltage (P < or = 0.01 for all). The heritability of QT interval duration in the age-, sex-, and R-R interval-adjusted model and in the fully adjusted model was 0.41 (SE, 0.07) and 0.40 (SE, 0.07; P < 10(-11) for both), respectively.
There is substantial heritability of adjusted QT interval in blacks, supporting the need for further investigation to identify its genetic determinants.
心电图QT间期延长是心源性猝死和药物性心律失常的危险因素。尽管与非西班牙裔白人相比，黑人的心源性猝死风险更高，但关于黑人QT间期持续时间的临床相关性和遗传度尚未得到充分研究。我们试图在杰克逊心脏研究中调查QT间期的潜在相关性并估计其遗传度。
杰克逊心脏研究包括居住在密西西比州杰克逊市的黑人样本，其中5302名在基线检查时有数据的个体可供研究。排除正在服用改变QT间期药物、患有束支传导阻滞、起搏心律、心房颤动/扑动或其他心律失常的杰克逊心脏研究参与者，最终得到4660名符合分析条件的个体样本。使用多变量逐步线性回归测试QT与潜在协变量之间的关系。在292个家庭的1297名杰克逊心脏研究参与者的子集中，使用顺序寡基因连锁分析程序估计遗传度；其余样本包括无亲属关系的个体。在逐步多变量线性回归分析中，与QT间期持续时间显著相关的协变量包括R-R间期、性别、QRS波时限、年龄、血清钾、高血压、体重指数、冠心病、利尿剂使用和索科洛夫-里昂电压（所有P≤0.01）。在年龄、性别和R-R间期调整模型以及完全调整模型中，QT间期持续时间的遗传度分别为0.41（标准误，0.07）和0.40（标准误，0.07；两者P<10⁻¹¹）。
黑人中校正QT间期具有较高的遗传度，支持进一步研究以确定其遗传决定因素的必要性。
