Accuracy of 12 lead ECG for diagnosis of posterior myocardial infarction

Abstract

Objective: To determine the accuracy of 12 lead ECG for diagnosis of acutePosterior Myocardial Infarction (MI) after its confirmation by 15 leads ECG.Methodology: This study was conducted in Cardiology Department, LadyReading Hospital Peshawar from January to July, 2012. Patients presentingto CCU with typical chest pain, pain epigastrium, sweating, nausea or vomitingand with admitting diagnosis of acute coronary syndrome (ACS) wereincluded. The diagnostic criteria for posterior MI on 12 leads ECG was whenR:S was more than 1:1 in V2 or there was tall R wave in V1 or V2 (more than Sin the same leads) or more than 2mm ST segment depression in anterior lead.Posterior MI was confirmed on 15 leads ECG taking it as a standard when STsegment elevation of >1mm was present in C7,8,9.Results: Out of 176 randomly selected patients, 90(51.1%) were male and86(48.9%) female; with mean age of 63 years. Out of these, 70 were in theage range of 51 to 60 years and 40 each in 41-50 and 61-70 years. Eighteenpatients had changes of posterior MI on 12 leads ECG and amongst them 10patients had true posterior MI on 15 leads ECG. We had 8 false positive caseson 12 leads ECG with no false negative cases after confirmation with 15 leads.Conclusion: The accuracy of 12 leads ECG for detection of posterior MI was55% after confirmation with 15 leads and there was no age and gender differencein its accuracy.