Angiographic and clinical implications of combined ST-segment elevation in anterior and inferior leads in acute myocardial infarction

Inferior ST-Segment Elevation Can Predict In-Hospital Mortality in Patients with Anterior Myocardial Infarction Complicated by Ventricular Septal Rupture

Background

Electrocardiogram (ECG) findings in patients with anterior wall myocardial infarction (MI) complicated by ventricular septal rupture (VSR) have rarely been studied.

Methods

We conducted a single-center retrospective study among patients with anterior MI complicated by VSR over the past ten years. The presence of ST-segment elevation (STE) in inferior leads and new onset of complete right bundle branch block (RBBB) on ECG were studied for the prediction of in-hospital mortality.

Results

Among the 85 patients enrolled, 45 (52.9%) were male, with a median age of 70 years. Sixty-five patients (76.5%) died in the hospital, and the remaining 20 patients (23.5%) had improved conditions and were discharged. Inferior STE was present in 35 patients (41.2%), including 32 patients in the death group and 3 patients in the survival group (P = 0.005). New-onset RBBB was present in 25 patients (29.4%), with 22 patients in the death group and 3 patients in the survival group (P = 0.103). Multivariate logistic regression showed that inferior STE was an independent predictor of in-hospital death in patients with anterior MI and VSR (OR: 14.488; 95% CI: 1.708-122.887; P = 0.014).

Conclusions

In patients with anterior MI complicated by VSR, inferior STE was associated with a higher risk of in-hospital mortality.

Clinical Paradox: Anterior Wall Myocardial Infarction with Predominant Inferior ST Elevation and No Variation in Coronary Anatomy in a PAI-1 Homozygote

Changes of the ST segment are commonly used as predictors of the culprit vessel during an acute myocardial infarction. In case of combined ST elevation in both inferior and anterior leads, these changes can be due to a distal occlusion of a “wrapped” left anterior descending artery (LAD) or a two-vessel disease. Our case of anterior wall myocardial infarction with inferior ST elevation and anterior ST depression shows that electrocardiographic changes during acute myocardial infarction cannot always be explained by logical sequelae of the injury current, vessel anatomy, and their irrigation territory.

Combined ST Elevation in a Case of Acute Myocardial Infarction: How to Identify the Infarct-related Artery?

Combined ST elevation in anterior and inferior ECG leads in acute myocardial infarction is not a rarity. It is both interesting and challenging to indentify the infarct related culprit artery. We report the case of a middle aged male with acute myocardial infarction whose admission ECG shows ST elevation in lead II, III, aVF as well as from V₁-V₃. 90% of such cases are due to single vessel occlusion - majority due to proximal RCA occlusion and the remaining due to mid to distal LAD occlusion. ECG features to differentiate between these two vascular occlusions are discussed. In this case at hand, lead III ST elevation of 2.5 mm and V₂/V₃≥ 1 indicates proximal RCA as the IRA and the same has been confirmed by pre-discharge coronary angiogram .

Isolated right ventricular infarction during percutaneous coronary intervention

Isolated right ventricular infarction (RVI) is an increasingly recognized cause of precordial ST-segment elevation (STE). A patient is described who developed STE in leads V1-V5 secondary to occlusion of the right ventricular branch during stent angioplasty to the right coronary artery. The pattern of precordial STE was thought to be suggestive of anteroseptal myocardial infarction because of progressive STE toward lead V3. Repeat angiography disclosed a patent left anterior descending artery. Subsequent scrutiny of the electrocardiogram (ECG) revealed that leads V2 and V3 were switched and ECG interpretation considering this technical error revealed STE in V2>V3, which favored RVI. Furthermore, the mean spatial ST vector was approximately +120° in the frontal plane producing ST-segment depression in lead I which argued against anteroseptal myocardial infarction and indicated right ventricular epicardial injury. This report highlights that analysis of the ECG using vector concepts is a useful adjunct to pattern recognition for the diagnosis of RVI.

Dominant right coronary artery occlusion entailing diffuse ST-segment elevation in the precordial leads

Right ventricular infarction (RVI) during inferior myocardial infarction (MI) is readily diagnosed when ST-segment elevation (STE) is recorded in lead V4R. RVI may also yield precordial STE and such an electrocardiographic (ECG) pattern may be misinterpreted as a sign of anterior MI. We present a case of inferior-right ventricular (RV) MI due to occlusion of a dominant right coronary artery manifesting STE in the inferior, all precordial and right chest leads. RV dilation due to acute ischemic insult facilitated STE in leads V1-V4 despite the dominant opponent inferior and posterolateral left ventricular injury current. This case illustrates that dilation of an infarcted RV should be considered when such an ECG pattern is encountered during inferior MI, specifically a dominant one. Awareness of the circumstances under which this ECG pattern develops facilitates avoidance of misinterpretation as a sign of anterior MI and proper management.