Relation between precordial ST segment depression and coronary lesion characteristic and its clinical implication in patients with acute inferior myocardial infarction

Objective:To investigate the relationship between coronary lesion characteristics and precordial ST segment depression and its clinical implication in patients with acute inferior myocardial infarction.Method:Sixty patients with first acute inferior myocardial infarction were divided into four groups on the basis of admission electrocardiogram.Group Ⅰ:patients with no precordial ST segment depression( n= 22),Group Ⅱ:those with St segment depression in leads v\-1 to v\-3( n= 12),Group Ⅲ:those with ST segment depression in leads v\-4 to v\-6( n= 12) and Group Ⅳ:those with ST segment depression in leads v\-1 to v\-6( n= 14).Data including history,ECG,myocardial enzymes,echocardiogram,coronary angiograms and postinfarction complications were analyzed.Result:The patients in Group Ⅱ had less LAD lesion than those in group Ⅰ(9.1% VS 47.1% P 0 05).Although similar frequence of LAD lesion in group Ⅰ,Ⅲ and Ⅳ,the patients with LAD stenosis more than 90% accounted for only 12.5% in goup Ⅰ but 83 3%,87 5% in group Ⅲ,Ⅳrespectively( P 0 05).compared with those in group Ⅰ,Those in group Ⅲ and Ⅳ had more LCX lesion,the patients in group Ⅳ had more multivessel involvement,lower LVEF and more hypotension condition.Conclusion:The precordial ST segment depression in v\-1 to v\-3 in patients with acute inferior myocardial infarction suggests lover incidence of LAD lesion,whereas the cause of ST segment depression in v\-4 to v\-6 or v\-1 to v\-6 may be due to extensive myocardial ischemia caused by severe stenosis of LAD and/or LCX.Patients with widespred precordial ST segment depression had higher incidence of hypotension and heart failure,more attention should be payed to these subgroup of patients. [