缺血分级对急性心肌梗死患者心律失常的影响

Effects of grade of ischemia on arrhythmia in patients with acute myocardial infarction

目的 通过对急性ST段抬高心肌梗死（STEMI）患者入院时心电图QRS波群形态进行缺血分级,探讨缺血分级对急性ST段抬高心肌梗死（STEMI）患者发生严重心律失常的预测意义.方法 为前瞻性观察研究,选择2003年7月至2008年4月在河北医科大学第二医院急诊科收治STEMI患者223例,纳入标准：（1）缺血性胸痛≥30 min.（2）心电图可见相邻两个或两个以上导联ST段抬高.（3）发病时间≤12 h.排除标准：（1）有束支传导阻滞；（2）有左室肥厚者.根据入院时心电图QRS波群形态进行缺血分级：2级缺血组（134例）：ST段抬高但QRS波终末部无改变；3级缺血组（89例）：除ST段抬高外,QRS波终末部扭曲且常伴R波增高与S波消失.两组患者在年龄、性别、冠心病危险因素等方面具有可比性.两组患者在发病12 h内均行溶栓治疗,观察心电图ST段变化；住院期间观察严重心律失常的发生率.结果 入院时和溶栓后2h,3级缺血组ST段抬高的幅度（∑ST）均显著大于2级缺血组（P＜0.01）,溶栓后2h,ST段回降率显著低于2级缺血组（P＜0.01）；3级缺血组肌酸激酶MB同工酶峰值显著高于2级缺血组（P＜0.01）；两组患者严重心律失常如室早、室速或室颤、Ⅱ度或Ⅲ度房室传导阻滞、窦性停搏的发生率差异无统计学意义（P＜0.05）,但3级缺血组严重心律失常的发生率有高于2级缺血组的趋势；多元Logistic回归分析显示：从发病到溶栓的时间和入院时心电图∑ST是急性ST段抬高心肌梗死（STEMI）患者发生严重心律失常发生的独立预测因素,而3级缺血的预测意义最强.结论 STEMI患者入院时心电图呈3级缺血,溶栓后易于出现ST段回降不良,是发生严重心律失常的独立预测因素.

Objective To evaluate clinical significance of the grade of ischemia by QRS complex on the admission electrocardiogram（ECG）to predict severe arrithmia in patients with acute ST-segment elevation myocardial infarction（STEMI）.Methods Patients with acute ST-segment elevation myocardial infarction（STEMI）admitted to emergency department from July 2003 to April 2008 were enrolled.A total of 223 patients met the criteria（ischemic chest pain ≥ 30 min,2 or more adjacent leads of ST segment elevation and onset time within 12 h）.Exclusion criteria were bundle branch block and left ventricular hypertrophy.All enrolled patients were divided into two groups based on the enrollment electrocardiogram：grade 2 ischemia（ST elevation without terminal QRS distortion; n =134）and grade 3 ischemia（ST elevation with terminal QRS distortion; n =89）.Patients of the two groups had comparable genderproportion,average age and coronary heart disease risk factors etc.All patients received thrombolytic therapy.The incidence rate of ST segment resolution（STR）and severe arrithmia in hospital stay were observed.Numerical variables were expressed mean ± standard deviation and compared by unpaired Student＇t test,Categorical variables were expressed percentage and compared by chi square test.Multiple logistic regression analysis was used to determine independent predictors of severe arrithmia.Results Patients with grade 3 ischemia had greater Σ ST on admission and 2 h after thrombolysis ECGs（P 〈 0.01）,the incidence rate of STR in patients with grade 3 ischemia was lower than that in patients with grade 2 ischemia（P 〈0.01）.The peak creatine kinase MB fraction was higher in patients with grade 3 ischemia than that in patients with grade 2 ischemia（P 〈 0.01）.There was no significant difference of the incidence of severe arrithmia,such as ventricular premature beat,ventricular tachycardia or fibrillation,second-degree or third-degree atrioventricular block,and sinus arrest between the two groups（P 〉 0.05）,but there was a trend of higher incidence of severe arrithmia in patients with grade 3 ischemia compared with that in patients with grade 2 ischemia.Multiple logistic regression analysis demonstrated that the independent predictors of severe arrithmia were duration from symptom to thrombolysis and initial.Σ ST,whereas grade 3 ischemia remained a strong predictor of severe arrithmia.Conclusions Grade 3 ischemia on admission is associated with lower incidence of STR in patients with ST-segment elevation myocardial infarction（STEMI）after thrombolysis and a strong predictor of severe arrithmia.