急性下壁心肌梗死患者心电图胸前导联ST段改变的临床意义

目的探讨急性下壁心肌梗死患者心电图胸前导联ST段改变与冠状动脉造影(CAG)所见冠状动脉病变部位的关系及其临床意义。方法 187例急性下壁心肌梗死患者,按入院时18导心电图胸前导联ST段改变分为3组,ST段无变化组(47例),ST段抬高组(16例),ST段压低组(124例);所有患者均行CAG。结果急性下壁心肌梗死伴胸前导联ST段抬高时多为右冠状动脉(RCA)近段闭塞(14例,82.3%),尤其是伴圆锥支动脉闭塞,与RCA中远端闭塞(2例,5.9%)比较差异有统计学意义(P0.01),且14例(73.7%)伴有右心功能不全和血流动力学障碍。下壁心肌梗死胸前导联ST段压低者可见于RCA、回旋支(LCX)闭塞及RCA、LCX闭塞与前降支(LAD)、对角支(D)病变的不同组合,其中LCX闭塞伴RCA病变者多表现为朐前ST V_4～V_6的压低,RCA闭塞伴LAD近端病变多有胸前ST V_1～V_6的压低,RCA伴D病变胸前ST V_1～V_3压低,与对照组比较差异有统计学意义(P0.05)。结论急性下壁心肌梗死合并胸前导联ST段抬高表明为RCA近段或丌口闭塞且多伴右心室心肌梗死和心功能不全;下壁心肌梗死伴胸前导联ST段压低提示为多支病变,ST V_1～V_3压低多伴有对角支严重狭窄,STV_1～V_6压低多伴有前降支的严重狭窄。

Clinical implications of precordial ST segment changes in patients with acute inferior myocardial infarction

Objective To study the implications of precordial ST segment changes in patients with acute inferior infarction and their relation to coronary artery lesions. Methods A total of 187 patients with new onset inferior myocardial infarction were divided into 3 groups according to the change pattern of precordial ST segment on admission electrocardiogram： patients with no precordial ST segment change （n = 47 ）, ST segment elevation （n = 16） and ST segment depression （n = 124）. All patients underwent coronary angiography. Results Fourteen patients with precordial ST segment elevation had the occluded fight coronary artery（RCA） at proximal part（ 82. 3% ）, especially conus branch occlusion and usually had unstable hemodynamic status due to fight ventricular infarction and dysfunction. Acute inferior myocardial infarction with chest leads ST segment depression indicated occlusion of RCA/left circumflex coronary artery （LCX） and different combination of RCA, LCX, left anterior descending coronary artery （LAD） and diagonal （D）. Most patients with ST segment depression in leads V4 - V6 were caused by occlusion of LCX with RCA stenosis;ST segment depression in leads V1 - V6 was caused by severe stenosis of LAD with occlusion of RCA （P 〈 0. 05 ） , whereas ST V1 - V3 segment depression meant lesion of diagonal coronary artery with occluded RCA （ P 〈 0. 05）. Conclusions Precordial ST segment elevation in patients with acute inferior myocardial infarction suggests occlusion of proximal or ostial RCA and usually have fight ventricular infarction and dysfunction. Acute inferior myocardial infarction with precordial ST segment depression indicates multivessel involvement.