Division of Cardiology, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, USA.
Heart Rhythm. 2011 Dec;8(12):1889-94. doi: 10.1016/j.hrthm.2011.07.029. Epub 2011 Jul 28.
Prediction of sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) could help to guide preventive interventions in at-risk patients. The QRST integral (∫QT) reflects intrinsic repolarization properties.
The objective of this study was to determine whether intracardiac ∫QT predicts VT/VF in the next few months in patients with implantable cardioverter defibrillators (ICDs).
Far-field (FF) and near-field (NF) right ventricular intracardiac electrograms (EGMs) were recorded via telemetry in 46 patients with structural heart disease and ICDs implanted for secondary prevention of sudden cardiac death. Epochs of 4.9 ± 0.4 minutes during sinus rhythm (mean heart rate 70.9 ± 15.2 beats/min) and ventricular pacing at 105 beats/min were analyzed. Mean ∫QT was calculated on FF and NF EGMs as the algebraic sum of areas under the QRST curve and adjusted by mean heart rate. Patients were followed up for at least 3 months. True VT/VF events treated by the ICD served as the end point.
During a mean follow-up of 4.6 months, 22 patients (48%) were treated for VT/VF. Unadjusted and adjusted by heart rate, FF EGM ∫QT in sinus rhythm was a significant predictor of VT/VF (unadjusted ∫QT hazard ratio 1.007; 95% confidence interval 1.002 to 1.0013; P = .007; adjusted ∫QT hazard ratio 1.68; 95% confidence interval 1.19 to 2.36; P = .002). The highest quartile of intracardiac ∫QT predicted VT/VF (log-rank test P = .042) and identified patients at risk with a specificity of 86% and positive predictive value of 73%.
Increased intracardiac FF EGM ∫QT predicts VT/VF in patients with structural heart disease and secondary prevention ICDs.
预测持续性室性心动过速（VT）/心室颤动（VF）有助于指导高危患者的预防干预。QRST 积分（∫QT）反映了内在复极特性。
本研究旨在确定结构性心脏病患者和植入埋藏式心脏复律除颤器（ICD）用于二级预防心源性猝死的患者中，心内∫QT 是否可预测未来数月的 VT/VF。
通过遥测技术记录 46 例结构性心脏病和植入 ICD 患者的远场（FF）和近场（NF）右心室内电图（EGM）。在窦性心律（平均心率 70.9±15.2 次/分）和 105 次/分的心室起搏时，分析 4.9±0.4 分钟的 EGM 段。FF 和 NF EGM 上的平均∫QT 通过 QRST 曲线下面积的代数和计算，并通过平均心率进行校正。患者至少随访 3 个月。ICD 治疗的真实 VT/VF 事件作为终点。
平均随访 4.6 个月期间，22 例患者（48%）因 VT/VF 接受治疗。未校正和校正心率后，窦性心律时的 FF EGM∫QT 是 VT/VF 的显著预测因子（未校正∫QT 危险比 1.007；95%置信区间 1.002 至 1.0013；P=0.007；校正∫QT 危险比 1.68；95%置信区间 1.19 至 2.36；P=0.002）。心内∫QT 的最高四分位数预测 VT/VF（对数秩检验 P=0.042），并识别出风险患者，特异性为 86%，阳性预测值为 73%。
结构性心脏病患者和二级预防 ICD 患者的 FF EGM 心内∫QT 增加可预测 VT/VF。
