Division of Cardiovascular Surgery Division of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Japan.
J Cardiovasc Electrophysiol. 2012 Jun;23(6):645-9. doi: 10.1111/j.1540-8167.2011.02244.x. Epub 2012 Apr 4.
The aim of the present study was to determine the prognostic implication of preoperative QT interval in relation to overall death and sudden cardiac death after coronary bypass surgery and to investigate the course of QT interval after surgery.
Of 812 consecutive patients undergoing isolated off-pump coronary surgery, 656 were retrospectively analyzed after excluding the 48 patients who were taking QT prolonging drugs and the 108 patients who had any of the following electrocardiographic findings: atrial fibrillation, pacemaker, QRS of >120 milliseconds, bundle branch block. QT intervals were corrected for heart rate (QTc) using Bazett's formula. Prolonged QTc was defined as QTc of ≥450 milliseconds in men (n = 144) and ≥470 milliseconds in women (n = 36). The 5-year cumulative rate of sudden cardiac death in patients with prolonged QTc was 25% against 4% for those with normal QTc (P = 0.01). The risk-adjusted hazard ratio (95% confidence interval) for the association between preoperative QTc and overall death was 1.47 (1.21-1.74) per 1-SD increase in QTc; and 2.38 (1.50-3.45) for prolonged versus normal QT. For sudden cardiac death, the respective ratios were 1.63 (1.32-2.25) per 1-SD increase in QTc; and 3.32 (2.14-4.23). QTc interval did not change during the first year after surgery, but increased significantly during the subsequent years. Patients with prolonged QTc before surgery had consistently longer QTc even after revascularization than those with normal QTc.
Preoperative QT interval was an independent predictor of overall death and sudden cardiac death after isolated coronary bypass surgery.
本研究旨在确定术前 QT 间期与冠状动脉旁路手术后总死亡率和心脏性猝死之间的相关性，并探讨术后 QT 间期的变化。
在 812 例连续接受非体外循环冠状动脉手术的患者中，排除了 48 例正在服用 QT 延长药物的患者和 108 例存在以下心电图表现的患者后，对 656 例患者进行了回顾性分析：心房颤动、起搏器、QRS 波>120 毫秒、束支传导阻滞。使用 Bazett 公式对 QT 间期进行心率校正（QTc）。将男性 QTc≥450 毫秒（n=144）和女性 QTc≥470 毫秒（n=36）定义为 QTc 延长。与 QTc 正常的患者相比，QTc 延长的患者 5 年累积心脏性猝死发生率为 25%，而 QTc 正常的患者为 4%（P=0.01）。术前 QTc 与全因死亡的风险比（95%置信区间）为每增加 1-SD 的 QTc 增加 1.47（1.21-1.74）；而对于 QTc 延长的患者则为 2.38（1.50-3.45）。对于心脏性猝死，相应的比值分别为每增加 1-SD 的 QTc 增加 1.63（1.32-2.25）；和 3.32（2.14-4.23）。术后第一年 QTc 间期没有变化，但随后几年显著增加。术前 QTc 延长的患者即使在血管重建后，其 QTc 也始终长于 QTc 正常的患者。
术前 QT 间期是冠状动脉旁路手术后总死亡率和心脏性猝死的独立预测因子。
