Department of Medicine I, Klinikum Grosshadern, Ludwig Maximilians University, Munich, Germany.
Am J Cardiol. 2010 Jul 15;106(2):216-20. doi: 10.1016/j.amjcard.2010.02.033.
The high incidence of sudden cardiac death in heart failure (HF) reflects electrophysiologic changes in response to myocardial failure. We previously showed that short-term variability of QT intervals (STV(QT)) identifies latent repolarization disorders in patients with drug-induced or congenital long QT syndrome. This study sought to determine (1) if STV(QT) is increased in patients with dilated cardiomyopathy (DC) and moderate congestive HF and (2) if increased STV(QT) is associated with ventricular arrhythmia in patients with HF. Sixty patients (53 +/- 12 years of age, 14 women) with DC and moderate HF (New York Heart Association classes II to III) were compared to matched controls. Twenty patients had implantable cardiac defibrillators secondary to a history of ventricular tachycardia (VT). Two cardiologists blinded to diagnosis manually measured QT intervals. Beat-to-beat variability of repolarization was determined from Poincaré plots of 30 consecutive QT intervals as was STV(QT). QTc intervals were comparable in patients and controls (419 +/- 36 vs 415 +/- 32 ms, respectively, p >0.05), whereas STV(QT) was significantly higher in patients with HF (7.8 +/- 3 vs 4.1 +/- 2 ms, respectively, p <0.05). STV(QT) was more increased in patients with a history of VT compared to those without VT (10.1 +/- 2 vs 6.6 +/- 2 ms, respectively, p <0.05). Increased STV(QT) and decreased ejection fraction were associated with a history of VT; however, STV(QT) was the strongest indicator. In conclusion, the present study demonstrates for the first time that STV(QT) is increased in patients with DC with HF. Patients with DC and HF and implantable cardiac defibrillators for secondary prevention had the highest STV(QT). Thus, increased STV(QT) in the context of moderate HF may reflect a latent repolarization disorder and increased susceptibility to sudden death in patients with DC, which is not identified by a prolonged QT interval.
心力衰竭（HF）中心律失常性猝死的高发率反映了心肌衰竭时电生理的变化。我们之前的研究表明，QT 间期短期变异（STV（QT））可识别药物诱导或先天性长 QT 综合征患者的潜在复极障碍。本研究旨在确定：（1）扩张型心肌病（DC）和中度充血性 HF 患者的 STV（QT）是否增加；（2）HF 患者中，STV（QT）增加是否与室性心律失常相关。将 60 例 DC 合并中度 HF（纽约心脏协会心功能 II 至 III 级）患者（53 ± 12 岁，14 例女性）与匹配的对照组进行比较。20 例患者因室性心动过速（VT）病史植入了心脏除颤器。两位对诊断不知情的心脏病专家手动测量 QT 间期。通过 30 个连续 QT 间期的 Poincaré 图确定复极的逐搏变异性，并确定 STV（QT）。患者和对照组的 QTc 间期相似（分别为 419 ± 36 ms 和 415 ± 32 ms，p > 0.05），而 HF 患者的 STV（QT）明显更高（分别为 7.8 ± 3 ms 和 4.1 ± 2 ms，p < 0.05）。有 VT 病史的患者的 STV（QT）比无 VT 病史的患者更高（分别为 10.1 ± 2 ms 和 6.6 ± 2 ms，p < 0.05）。增加的 STV（QT）和降低的射血分数与 VT 病史相关；然而，STV（QT）是最强的指标。总之，本研究首次证明，HF 患者的 DC 中 STV（QT）增加。HF 合并 DC 且植入心脏除颤器用于二级预防的患者的 STV（QT）最高。因此，中度 HF 时 STV（QT）的增加可能反映了潜在的复极障碍，增加了 DC 患者猝死的易感性，而这一点不能通过延长 QT 间期来识别。
