Haigney Mark C, Zareba Wojciech, Nasir Javed M, McNitt Scott, McAdams Douglas, Gentlesk Philip J, Goldstein Robert E, Moss Arthur J
Division of Cardiology, Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.
Heart Rhythm. 2009 Feb;6(2):180-6. doi: 10.1016/j.hrthm.2008.10.045. Epub 2008 Nov 6.
Healthy women have longer QT intervals and more drug-induced proarrhythmia compared to men, yet those given implantable cardioverter-difibrillators (ICDs) for ischemic cardiomyopathy have fewer episodes of ventricular tachycardia/ventricular fibrillation (VT/VF) than men. The role of repolarization duration and stability in arrhythmogenesis in men and women with structural heart disease has not been explored.
The purpose of this study was to analyze repolarization differences between men and women and their relation to the risk of VT/VF.
Multicenter Automatic Defibrillator Trial II study patients underwent 10-minute, resting digitized recordings at study entry. QT and heart rate were measured for each beat with a semiautomated method. QT variance was normalized for mean QT (QTVN) or for heart rate variance (QTVI). Spectral analysis of heart rate and QT time series was performed; coherence was indexed to quantify consistency of heart rate and QT power spectra. The incidence of VT/VF was determined by ICD interrogation.
There were 805 usable recordings (142 females); 463 received ICDs (86 females). There was no gender difference in mean or median QT, QTc, or heart rate. QTVN and QTVI were slightly (but significantly) higher, and the mean coherence was lower in women. In a Cox multivariate analysis, increased QTVN or QTVI (top quartile) was associated with a significantly higher risk for VT/VF in men (QTVN hazard ratio (HR) 2.2; confidence interval [CI] 1.4-3.4; P = .001; QTVI HR 1.9; CI 1.2-3.0; P = .006) but not in women, while reduced coherence (bottom quartile) predicted VT/VF in women (HR 3.3; CI 1.2-9.0; P = .021) but not in men.
In post-myocardial infarcation patients with depressed ejection fraction, both women and men manifest increased temporal variability in the QT interval. In men, QT variability by itself raised arrhythmic risk. In women, however, QT variability dissociated from HR variability (low coherence) appeared to be a uniquely significant predictor of arrhythmic events.
与男性相比，健康女性的QT间期更长，药物诱发的心律失常更多，但因缺血性心肌病接受植入式心脏复律除颤器（ICD）治疗的女性，室性心动过速/心室颤动（VT/VF）发作次数比男性少。尚未探讨复极持续时间和稳定性在患有结构性心脏病的男性和女性心律失常发生中的作用。
本研究旨在分析男性和女性之间的复极差异及其与VT/VF风险的关系。
多中心自动除颤器试验II研究的患者在研究开始时进行了10分钟的静息数字化记录。使用半自动方法测量每搏的QT和心率。QT离散度通过平均QT（QTVN）或心率离散度（QTVI）进行标准化。对心率和QT时间序列进行频谱分析；相干性用于量化心率和QT功率谱的一致性。通过ICD问询确定VT/VF的发生率。
共有805份可用记录（142名女性）；463人接受了ICD治疗（86名女性）。QT、QTc或心率的均值或中位数无性别差异。女性的QTVN和QTVI略高（但有显著差异），平均相干性较低。在Cox多变量分析中，QTVN或QTVI增加（最高四分位数）与男性VT/VF风险显著升高相关（QTVN风险比（HR）2.2；置信区间[CI]1.4 - 3.4；P = 0.001；QTVI HR 1.9；CI 1.2 - 3.0；P = 0.006），但与女性无关，而相干性降低（最低四分位数）可预测女性的VT/VF（HR 3.3；CI 1.2 - 9.0；P = 0.021），但与男性无关。
在射血分数降低的心肌梗死后患者中，男性和女性的QT间期时间变异性均增加。在男性中，QT变异性本身会增加心律失常风险。然而，在女性中，与心率变异性无关的QT变异性（低相干性）似乎是心律失常事件的唯一重要预测因素。
