Clinical Significance of ST Segment Elevation in Posterior Leads V7, V8 and V9 in Patients with Acute Inferior Wall Myocardial Infarction

Dipesh Pradhan,Rajina Shrestha,Sun Jian,Madhu Gupta,Sanaya Karki

doi:10.4172/2329-9517.1000106

Dipesh Pradhan, Rajina Shrestha + Show 3 more

Open Access

https://doi.org/10.4172/2329-9517.1000106

Copy DOI

Abstract

Objectives: The aim of the study was to assess the role of ST segment elevation in the Posterior leads V7, V8, and V9 for the diagnosis of acute posterior wall infarction and the identification of infarct related artery (IRA) in patients with acute inferior wall MI. Background: The posterior wall infarction is difficult to diagnose through standard 12 lead ECG alone, especially in the acute setting. Methods: In our retrospective study, 121 patients (101 male, 20 female) with an inferior acute MI, were included. They were divided into two groups according to the presence (Group A: mean age 60.00±10.05 years) or absence (Group B: mean age 57.65 ± 12.86 years) of ST segment elevation in leads V7, V8, V9. Complete demographic data were recorded in all subjects, the infarct size was estimated by CPK MB, left ventricular function was assessed by echocardiographically and infarct related artery patency was evaluated by coronary angiography. Results: Group A patients had a higher frequency of Left cirucumflex occlusion than group B patients (n=33, 27.3% vs. n=4, 3.3%, p=0.0001). Group A had a more extensive infarction, as is shown by CPK MB values (90.12 ± 33.42 vs 45 ± 38.28, P= 0.0001) but with no difference in left ventricular ejection fraction. Conclusion: ST segment elevation in posterior leads helps to diagnose left circumflex artery as a culprit IRA in an acute inferior wall MI with extensive infarct area involving posterolateral walls.

Highlights

ECG diagnosis of a posterior wall myocardial infarction is difficult to diagnose through the standard 12 lead ECG, especially in the acute stage
The posterior wall MI may occur as an isolated event or often associated with an inferior wall myocardial infarction Posterior leads V7, V8 and V9 are usually ignored but it is suggested that these leads can provide ECG information that is useful for characterization of inferior AMI and diagnosis of posterior wall MI [1,2]. 15 or 18 leads ECG should be performed to correctly diagnose culprit artery in inferior wall MI
Inferior wall MI with ST elevation in lead III>II was frequently associated with group B patients than group A patients (n=72, 59.5% vs. n=19, 15.7%, p=0.0001) whereas ST elevation II>III favors group A patients than Group B patients (n=22, 18.2% vs. n=8, 6.6%, P=0.0001) as shown in table 2

Summary

Introduction

ECG diagnosis of a posterior wall myocardial infarction is difficult to diagnose through the standard 12 lead ECG, especially in the acute stage. 15 or 18 leads ECG should be performed to correctly diagnose culprit artery in inferior wall MI. ST elevation in inferior and posterior leads (V7, V8 and V9) is usually associated with occlusion of the left circumflex artery with the involvement of large infarct zone and complications [3,4]. ECG detection of posterior infarction is associated with concomitant ST depression in leads V1 to V3. These changes are neither sensitive nor specific [5,6,7]. The posterior wall infarction is difficult to diagnose through standard 12 lead ECG alone, especially in the acute setting

Objectives

Methods

Results

Discussion

Conclusion