QT-interval evaluation in primary percutaneous coronary intervention of ST-segment elevation myocardial infarction for prediction of myocardial salvage index

Assessing the efficacy of revascularization therapy in patients with ST-segment elevation myocardial infarction (STEMI) is extremely important in order to guide subsequent management and assess prognosis. We aimed to determine the relationship between corrected QT-interval (QTc) changes on standard sequential ECG and myocardial salvage index in anterior STEMI patients after successful primary percutaneous coronary intervention. Fifty anterior STEMI patients treated by primary percutaneous coronary intervention underwent quantitative ECG analysis and cardiac magnetic resonance. For each patient the difference (ΔQTc) between the QTc of ischemic myocardium (maximum QTc in anterior leads) versus remote myocardium (minimum QTc in inferior leads) during the first six days after STEMI was measured. The QTc in anterior leads was significantly longer than QTc in inferior leads (p<0.0001). At multivariate analysis, ΔQTC and peak troponin I were the only independent predictors for late gadolium enhancement while ΔQTc and left ventricular ejection fraction were independent predictors of myocardial salvage index <60%. The receiver operative curve of ΔQTc showed an area under the curve of 0.77 to predict a myocardial salvage index <0.6. In conclusion, in a subset of patients with a first occurrence of early revascularized anterior STEMI, ΔQTc is inversely correlated with CMR-derived myocardial salvage index and may represent a useful parameter for assessing efficacy of reperfusion therapy.

评估ST段抬高型心肌梗死（ST-segment elevation myocardial infarction, STEMI）患者血运重建治疗的疗效，对于指导后续临床管理及预后评估均具有至关重要的意义。本研究旨在明确成功接受直接经皮冠状动脉介入治疗（primary percutaneous coronary intervention, PPCI）的前壁STEMI患者中，标准序列心电图上校正QT间期（corrected QT-interval, QTc）的变化与心肌挽救指数之间的关联。本研究共纳入50例接受直接经皮冠状动脉介入治疗的前壁STEMI患者，对其开展定量心电图分析与心脏磁共振（cardiac magnetic resonance, CMR）检查。针对每例患者，测量其于STEMI发病后前6日内，缺血心肌（前壁导联的最大QTc）与远隔非缺血心肌（下壁导联的最小QTc）之间的QTc差值（ΔQTc）。结果显示，前壁导联的QTc显著长于下壁导联（p<0.0001）。多变量分析表明，ΔQTc与肌钙蛋白I峰值是晚期钆强化的唯一独立预测因子；而ΔQTc与左心室射血分数则是心肌挽救指数<60%的独立预测因子。ΔQTc的受试者工作特征（receiver operating characteristic, ROC）曲线显示，其预测心肌挽救指数<0.6的曲线下面积为0.77。综上，在首次发生且接受早期血运重建的前壁STEMI患者亚组中，ΔQTc与心脏磁共振成像获取的心肌挽救指数呈负相关，或可作为评估再灌注治疗疗效的可靠参数。