From the Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada (M.D., A.M.S., S.N., K.V., D.A.S., G.T., R.D., V.S.C.); Department of Cardiology, Freeman Hospital, Newcastle Upon Tyne, United Kingdom (M.D.); Division of Cardiology, St. Michael's Hospital, Toronto, Ontario, Canada (A.P.); Division of Cardiology, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada (E.C.); and Department of Electrical and Computer Engineering, Ryerson University, Toronto, Ontario, Canada (S.K.).
Circ Arrhythm Electrophysiol. 2017 Jul;10(7). doi: 10.1161/CIRCEP.116.004874.
Cardiomyopathy patients are at risk of sudden death, typically from scar-related abnormalities of electrical activation that promote ventricular tachyarrhythmias. Abnormal intra-QRS peaks may provide a measure of altered activation. We hypothesized that quantification of such QRS peaks (QRSp) in high-resolution ECGs would predict arrhythmic events in implantable cardioverter-defibrillator (ICD)-eligible cardiomyopathy patients.
Ninety-nine patients with ischemic or non-ischemic dilated cardiomyopathy undergoing prophylactic ICD implantation were prospectively enrolled (age 62±11 years, left ventricular ejection fraction 27±7%). High-resolution (1024 Hz) digital 12-lead ECGs were recorded during intrinsic rhythm. QRSp was quantified for each precordial lead as the total number of low-amplitude deflections that deviated from their respective naive QRS template. The primary end point of arrhythmic events was defined as appropriate ICD therapy or sustained ventricular tachyarrhythmias. After a median follow-up of 24 (15-43) months, 20 (20%) patients had arrhythmic events. Both QRSp and QRS duration were greater in those with arrhythmic events (both <0.001) and this was consistent for QRSp for both cardiomyopathy types. In a multivariable Cox regression model that included age, left ventricular ejection fraction, QRS duration, and QRSp, only QRSp was an independent predictor of arrhythmic events (hazard ratio, 2.1; <0.001). Receiver operating characteristic analysis revealed that a QRSp ≥2.25 identified arrhythmic events with greater sensitivity (100% versus 70%, <0.05) and negative predictive value (100% versus 89%, <0.05) than QRS duration ≥120 ms.
QRSp measured from high-resolution digital 12-lead ECGs independently predicts ventricular tachyarrhythmias in ICD-eligible cardiomyopathy patients. This novel QRS morphology index has the potential to improve sudden death risk stratification and patient selection for prophylactic ICD therapy.
心肌病患者有发生猝死的风险，通常是由疤痕相关的电激活异常引起的室性心动过速和心律失常。异常的 QRS 波峰可能是激活改变的一种度量。我们假设在植入式心脏复律除颤器（ICD）合格的心肌病患者中，对高分辨率心电图（ECG）中的这种 QRS 波峰（QRSp）进行定量分析，将预测心律失常事件。
前瞻性纳入 99 例缺血性或非缺血性扩张型心肌病行预防性 ICD 植入的患者（年龄 62±11 岁，左心室射血分数 27±7%）。在固有节律期间记录高分辨率（1024 Hz）数字 12 导联 ECG。每个前导导联的 QRSp 均作为偏离各自原始 QRS 模板的低幅度偏转的总数进行量化。心律失常事件的主要终点定义为适当的 ICD 治疗或持续性室性心动过速和心律失常。中位随访 24（15-43）个月后，20（20%）例患者发生心律失常事件。有和无心律失常事件的患者的 QRSp 和 QRS 持续时间均较大（均<0.001），且这两种类型的心肌病的 QRSp 均一致。在包括年龄、左心室射血分数、QRS 持续时间和 QRSp 的多变量 Cox 回归模型中，只有 QRSp 是心律失常事件的独立预测因子（危险比，2.1；<0.001）。接受者操作特征分析显示，QRSp≥2.25 比 QRS 持续时间≥120 ms 能更敏感（100%比 70%，<0.05）和更具阴性预测值（100%比 89%，<0.05）地识别心律失常事件。
从高分辨率数字 12 导联 ECG 测量的 QRSp 独立预测 ICD 合格的心肌病患者的室性心动过速和心律失常。这种新的 QRS 形态学指数有可能改善猝死风险分层和预防性 ICD 治疗的患者选择。
