Sandwell and City Hospitals NHS Trust, Bham B18 7QH, UK.
Europace. 2010 Feb;12(2):266-70. doi: 10.1093/europace/eup376. Epub 2009 Nov 30.
Therapeutic hypothermia (TH) is used in neuroprotection following cardiac arrest due to ventricular tachycardia (VT) and ventricular fibrillation (VF). Accidental hypothermia is itself known to cause prolongation of the corrected QT interval (QTc). QTc prolongation can cause polymorphic VT and VF. If this also occurs in TH, it may induce refibrillation. We investigated the effect of TH on the QTc interval.
Prospective case series of all patients undergoing TH following cardiac arrest following VT/VF at our hospital between July 2008 and January 2009. We studied the effect of temperature on QTc. All electrocardiograms (ECGs) undertaken during TH were studied and compared with the ECG prior to this. Four patients underwent TH. A total of 10 ECGs were undertaken during TH. The QTc was normal prior to TH. It became prolonged (>460 ms) in all cases during TH and normalized after cessation of TH, apart from Patient 4 who did not have an ECG post-TH since she died from cardiogenic shock. There was a negative correlation between temperature and QTc (Pearson's correlation coefficient, r= -0.71).
Our series illustrates QTc prolongation during TH. This carries potential for refibrillation. Guidelines on ECG monitoring during TH are needed, especially since hypothermic myocardium is intrinsically prone to arrhythmias and commonly used antiarrythmic drugs such as amiodarone can prolong the QTc.
心脏骤停后，由于室性心动过速（VT）和心室颤动（VF），治疗性低温（TH）用于神经保护。众所周知，意外低温本身会导致校正 QT 间期（QTc）延长。QTc 延长可引起多形性 VT 和 VF。如果这也发生在 TH 中，它可能会引起再纤维颤动。我们研究了 TH 对 QTc 间期的影响。
这是我们医院 2008 年 7 月至 2009 年 1 月期间所有 VT/VF 心脏骤停后接受 TH 的患者的前瞻性病例系列研究。我们研究了温度对 QTc 的影响。研究了 TH 期间进行的所有心电图（ECG），并与之前的 ECG 进行了比较。有 4 名患者接受了 TH。在 TH 期间共进行了 10 次 ECG。TH 前 QTc 正常。在 TH 期间，所有病例的 QTc 均延长（>460 ms），除了第 4 例患者，由于她死于心源性休克，TH 后没有进行 ECG 检查。温度与 QTc 呈负相关（Pearson 相关系数，r=-0.71）。
我们的系列研究说明了 TH 期间 QTc 延长。这可能会导致再纤维颤动。需要制定 TH 期间 ECG 监测指南，特别是因为低温心肌本身容易发生心律失常，并且常用的抗心律失常药物（如胺碘酮）可延长 QTc。
