Whiting School of Engineering, Department of Biomedical Engineering, The Johns Hopkins University Baltimore, MD, USA.
Front Physiol. 2013 Aug 12;4:208. doi: 10.3389/fphys.2013.00208. eCollection 2013.
While it is known that elevated baseline intracardiac repolarization lability is associated with the risk of fast ventricular tachycardia (FVT)/ventricular fibrillation (VF), the effect of its longitudinal changes on the risk of FVT/VF is unknown.
Near-field (NF) right ventricular (RV) intracardiac electrograms (EGMs) were recorded every 3-6 months at rest in 248 patients with structural heart disease [mean age 61.2 ± 13.3; 185(75%) male; 162(65.3%) ischemic cardiomyopathy] and implanted cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) [201 (81%) primary prevention]. Intracardiac beat-to-beat QT variability index (QTVINF) was measured on NF RV EGM. During the first study phase (median 18 months), participants made on average 2.4 visits. Then remote follow-up was continued for an additional median period of 3 years. Average QTVINF did not change during the first year after ICD implantation (-0.342 ± 0.603 at baseline vs. -0.262 ± 0.552 at 6 months vs. -0.334 ± 0.603 at 12 months); however, it decreased thereafter (-0.510 ± 0.603 at 18 months; P = 0.042). Adjusted population-averaged GEE model showed that the odds of developing FVT/VF increased by 75% for each 1 unit increase in QTVINF. (OR 1.75 [95%CI 1.05-2.92]; P = 0.031). However, individual patient-specific QTVINF trends (increasing, decreasing, flat) varied from patient to patient. For a given patient, the odds of developing FVT/VF were not associated with increasing or decreasing QTVINF over time [OR 1.27; (95%CI 0.05-30.10); P = 0.881].
While on average the odds of FVT/VF increased with an increase in QTVINF, patient-specific longitudinal trends in QTVINF did not affect the odds of FVT/VF.
虽然已知基础心内复极不稳定性升高与快速室性心动过速（FVT）/心室颤动（VF）风险相关，但尚不清楚其纵向变化对 FVT/VF 风险的影响。
248 例结构性心脏病患者[平均年龄 61.2±13.3；185（75%）男性；162（65.3%）缺血性心肌病]和植入式心脏复律除颤器（ICD）或心脏再同步治疗除颤器（CRT-D）[201（81%）一级预防]接受了每 3-6 个月在休息时进行的近场（NF）右心室（RV）心内电图（EGM）记录。在 NF RV EGM 上测量心内逐搏 QT 变异性指数（QTVINF）。在第一个研究阶段（中位时间 18 个月），参与者平均就诊 2.4 次。然后继续进行远程随访，中位时间另外 3 年。ICD 植入后第一年平均 QTVINF 无变化（植入前-0.342±0.603 与植入后 6 个月-0.262±0.552 与植入后 12 个月-0.334±0.603）；然而，此后有所下降（植入后 18 个月-0.510±0.603；P=0.042）。调整后的人群平均 GEE 模型显示，QTVINF 每增加 1 单位，FVT/VF 发生的几率增加 75%。（OR 1.75[95%CI 1.05-2.92]；P=0.031）。然而，每位患者的特定个体 QTVINF 趋势（增加、减少、平稳）各不相同。对于特定患者，随着时间的推移，QTVINF 的增加或减少与 FVT/VF 的发生无关[OR 1.27；（95%CI 0.05-30.10）；P=0.881]。
虽然平均而言，QTVINF 增加与 FVT/VF 发生的几率增加相关，但特定患者的 QTVINF 纵向趋势并不影响 FVT/VF 发生的几率。
