Department of Anesthesiology, Washington University, St. Louis, MO, USA.
Anesthesiology. 2012 Aug;117(2):321-8. doi: 10.1097/ALN.0b013e31825e6eb3.
Abnormal cardiac repolarization, indicated by a prolongation of the QT interval, increases the risk for torsades de pointes, a potentially life-threatening arrhythmia. Many perioperatively administered drugs and conditions prolong the QT interval. Despite several reports of perioperative torsades de pointes, systematic evidence regarding perioperative QT interval prolongation is limited.
Serial postoperative 12-lead electrocardiograms were obtained from 469 adult patients undergoing major noncardiac surgery under general anesthesia. Heart rate corrected QT-interval duration (Fridericia formula) was the primary outcome. All perioperatively administered drugs were recorded. Emphasis was placed on absolute QTc prolongation greater than 500 ms and relative increases of 30 and 60 ms.
At the end of surgery, 80% of the patients (345 of 429) experienced a significant QTc interval prolongation (ΔQTc 23 ± 26 ms (mean and SD), 95% CI 20-25 ms, P less than 0.001). Approximately 51% (219 of 429) had a QTc greater than 440 ms, and 4% (16 of 429) a QTc greater than 500 ms. In 39% (166 of 429), the ΔQTc was greater than 30 ms, in 8% (34 of 429) >60 ms, and in greater than 0.5% (2 of 429) >100 ms. No changes in ΔQTc occurred at subsequent time points. One patient developed torsades de pointes with a ΔQTc: 29 ms (0.4% incidence rate). Several drugs had a large effect on ΔQTc: isoflurane, methadone, ketorolac, cefoxitin, zosyn, unasyn, epinephrine, ephedrine, and calcium. Postoperative body temperature had a weak negative correlation with ΔQTc (r = -0.15, P = 0.02); serum magnesium, potassium, and calcium concentrations were not correlated.
Postoperative QT-interval prolongation is common. Several perioperatively administered drugs are associated with a substantial QT-interval prolongation. The exact cause and its clinical relevance are, however, unclear. Nevertheless, an association between postoperative QT prolongation and risk for torsades de pointes is likely.
QT 间期延长表明心脏复极异常，增加尖端扭转型室性心动过速（TdP）的风险，TdP 是一种潜在的危及生命的心律失常。许多围手术期给予的药物和情况会延长 QT 间期。尽管有几例围手术期尖端扭转型室性心动过速的报告，但关于围手术期 QT 间期延长的系统证据有限。
对 469 名在全身麻醉下接受非心脏大手术的成年患者进行术后连续 12 导联心电图检查。心率校正 QT 间期（Fridericia 公式）是主要观察终点。记录所有围手术期给予的药物。强调的是绝对 QTc 延长大于 500ms 和相对增加 30ms 和 60ms。
在手术结束时，80%的患者（429 例中的 345 例）经历了显著的 QTc 间期延长（ΔQTc 23±26ms（平均值和标准差），95%CI 20-25ms，P＜0.001）。约 51%（429 例中的 219 例）的 QTc 大于 440ms，4%（429 例中的 16 例）的 QTc 大于 500ms。39%（429 例中的 166 例）的 ΔQTc 大于 30ms，8%（429 例中的 34 例）大于 60ms，大于 0.5%（429 例中的 2 例）大于 100ms。在随后的时间点，ΔQTc 没有变化。1 例患者发生 TdP，ΔQTc 为 29ms（发生率为 0.4%）。几种药物对 ΔQTc 有很大的影响：异氟烷、美沙酮、酮咯酸、头孢西丁、Zosyn、Unasyn、肾上腺素、麻黄碱和钙。术后体温与 ΔQTc 呈弱负相关（r=-0.15，P=0.02）；血清镁、钾和钙浓度无相关性。
术后 QT 间期延长很常见。几种围手术期给予的药物与明显的 QT 间期延长有关。然而，确切的原因及其临床意义尚不清楚。尽管如此，术后 QT 延长与尖端扭转型室性心动过速的风险之间可能存在关联。
