Electrocardiogram in patients with acute inferior myocardial infarction due to occlusion of circumflex artery

Diagnostic value of electrocardiographic indices in discriminating the culprit vessel based on the coronary dominancy in inferior acute myocardial infarction

BACKGROUND

Identifying the culprit during inferior myocardial infarction (MI) is still challenging. We determined the diagnostic effect of electrocardiographic (ECG) indices in identifying the culprit vessel of acute MI and the impact of coronary artery dominance on it.

METHODS

This cross-sectional study included patients with acute inferior MI who presented to Imam Khomeini Hospital and Tehran Heart Center and underwent primary PCI within 12 h of the onset of symptoms. A standard 12‑lead ECG was recorded and interpreted by two cardiologists. Based on the coronary angiography, the patients were divided into two groups of LCX or RCA involvement and were compared for general variables and ECG indices. The diagnostic values of the ECG indices for predicting the culprit vessel were then calculated.

RESULTS

We evaluated 411 patients with inferior STEMI (321 [77.5%] male, age 58.1 ± 11.1 years). RCA was the culprit vessel in 286 patients (69.1%) and LCX in 128 patients (30.9%). 321 patients (77.5%) were right dominant, 40 (9.7%) patients were left dominant, and 53 patients (12.8%), were codominant. Coronary dominance had minimal impact on the ECG indices regarding culprit identification even after adjustment for confounders. STE in lead III > lead II had the highest sensitivity for detecting RCA as the culprit (sensitivity: 89.2% and specificity: 57.8%). STE ≥0.1 mV in V5 or V6 leads had the highest sensitivity for detecting LCX as the culprit (sensitivity: 51.6, specificity: 93.7%).

CONCLUSION

In inferior STEMI, ECG indices can predict the culprit vessel with acceptable sensitivity and specificity independent of coronary artery dominance.

Correlations between Cardiovascular Risk Factors and Ventricular Arrhythmias Following Primary Percutaneous Coronary Intervention in Patients with ST-Elevation Myocardial Infarction

Background

Ventricular arrhythmias (VAs), which result from acute myocardial infarction and revascularization, are preventable causes of sudden cardiac death. This study aimed to determine the incidence, types, and risk factors of VAs in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention (PCI).

Methods

This cross-sectional study was conducted at the cardiology department of a tertiary care cardiac center in Zanjan, Iran. All the patients were monitored during hospitalization, and the incidence of cardiac arrhythmias and the outcomes were recorded.

Results

Among 315 patients, the mean age was 62.14±10.11 years, and 76.2% were male. Male gender was significantly associated with VA occurrence (P=0.038). Among the patients, 50.5% had VAs, of which 26.4% were sustained ventricular tachycardia (sustained VT) and ventricular fibrillation (VF). Sustained VT and VF, but not total arrhythmias, were more common in anterior infarctions. Most arrhythmias occurred during the first 12 hours, and frequent premature ventricular contractions (43.3%) and idioventricular rhythm (20.1%) were the most common. A history of PCI and coronary artery bypass grafting (CABG) was associated with substantially reduced arrhythmias (P=0.017 and P=0.013, respectively). However, cardiovascular risk factors exerted no statistically significant effects on the VA type.

Conclusion

Approximately half of our patients experienced reperfusion-induced VAs. Overall, gender and a history of PCI and CABG were significantly associated with VA occurrence. Therefore, males and patients without a positive history of PCI and CABG should receive antiarrhythmic drugs as a precaution.

Identifying the culprit artery via 12-lead electrocardiogram in inferior wall ST-segment elevation myocardial infarction: A meta-analysis

BACKGROUND

Inferior wall ST-segment elevation myocardial infarction (STEMI) is mostly caused by acute occlusion of right coronary artery (RCA) and left circumflex artery (LCX). Several methods and algorithms using 12-lead ECG were developed to localize the lesion in inferior wall STEMI. However, the diagnostic properties of these methods remain under-recognized.

AIMS

The aim of this meta-analysis is to compare the diagnostic properties among the methods of identifying culprit artery in inferior wall STEMI using 12-lead ECG.

METHODS

We performed a meta-analysis to calculate the pooled sensitive, specificity, area under the curve (AUC) and diagnostic odds ratio (DOR) of each method.

RESULTS

Thirty-three studies with 4414 participants were included in the analysis. Methods using double leads had better diagnostic properties, especially ST-segment elevation (STE) in III > II [with pooled sensitivity 0.89 (0.84-0.93), specificity 0.68 (0.57-0.79), DOR 17 (9-32), AUC 0.88 (0.85-0.91)], ST-segment depression (STD) in aVL > I [with pooled sensitivity 0.82 (0.72-0.90), specificity 0.69 (0.48-0.86), DOR 11 (4-29), AUC 0.85 (0.81-0.88)], and STD V3/STE III ≤1.2 [with pooled sensitivity 0.88 (0.78-0.95), specificity 0.59 (0.42-0.75), DOR 12 (5-27), AUC 0.82 (0.78-0.85)]. Diagnostic algorithms, including Jim score[pooled sensitivity 0.70 (0.55-0.85), specificity 0.88 (0.75-0.96)], Fiol's algorithm [pooled sensitivity 0.54 (0.44-0.62), specificity 0.92 (0.88-0.96)] and Tierala's algorithm [pooled sensitivity 0.60 (0.49-0.71), specificity 0.91 (0.86-0.96)], were not superior to these simple methods.

CONCLUSIONS

Our meta-analysis indicated that diagnostic methods using double leads had better properties. STE in III > II together with STD in aVL > I may be the most ideal method, for its accuracy and convenience.

Electrocardiographic Distinction of Left Circumflexand Right Coronary Artery Occlusion in PatientsWith Inferior Acute Myocardial Infarction

Previously reported electrocardiographic (ECG) criteria to distinguish left circumflex (LCCA) and right coronary artery (RCA) occlusion in patients with acute inferior ST-segment elevation myocardial infarction (STEMI) afford a modest diagnostic accuracy. We aimed to develop a new algorithm overcoming limitations of previous studies. Clinical, ECG, and coronary angiographic data were analyzed in 230 nonselected patients with acute inferior STEMI who underwent primary percutaneous coronary intervention. A decision-tree analysis was used to develop a new ECG algorithm. The diagnostic accuracy of reported ECG criteria was reviewed. LCCA occlusion occurred in 111 cases and RCA in 119. We developed a 3-step algorithm that identified LCCA and RCA occlusion with a sensitivity of 77%, specificity of 86%, accuracy of 82%, and Youden index of 0.63. The area under the ROC curve was 0.85 and resulted 0.82 after a 10-fold cross validation. The key leads for LCCA occlusion were V3 (ST depression in V3/ST elevation in III >1.2) and V6 (ST elevation ≥0.1 mV or greater than III). The key leads for RCA occlusion were I and aVL (ST depression ≥ 0.1 mV). Fifteen of 21 reviewed studies had less than 20 cases of LCCA occlusion, only 48% performed primary percutaneous coronary intervention, and previous infarction or multivessel disease were often excluded. The diagnostic accuracy of reported ECG criteria decreased when applied to our study population. In conclusion, we report a simple and highly discriminative 3-step ECG algorithm to differentiate LCCA and RCA occlusion in an "all comers" population of patients with acute inferior STEMI. The diagnostic key ECG leads were V3 and V6 for LCCA and I and aVL for RCA occlusion.