European Journal of Cardiovascular Medicine

Cardiovascular disease (CVD) accounts for 30% of global deaths annually, with 80% occurring in developing countries. 1Acute myocardial infarction (AMI) has a 30-day mortality rate of 30%, and despite advancements, 1 in 25 survivors dies within a year. Mortality is significantly higher in elderly patients.2

The electrocardiogram (ECG) remains vital for AMI diagnosis and management. Acute risk stratification relies on clinical parameters, biomarkers, and 12-lead ECG. 3ECG aids in early detection, infarct-related artery identification, and perfusion therapy decisions. ST-segment elevation patterns help predict myocardial risk and guide revascularization urgency. 4Moreover, ECG indicators of reperfusion serve as prognostic markers. While ECG reflects myocardial electrophysiology during ischemia, coronary angiography defines vessel anatomy.5

Accordingly, many algorithms have been developed to identify the infarct-related artery and the occlusion site, especially in cases of inferior STEMI.6 Hence present study was carried out to determine the culprit artery in the case of acutemyocardial infarction with electrocardiogram and to compare with coronary angiogram.

 AIM

• To determine the culprit artery in the case of acutemyocardial infarction with electrocardiogram and to compare with coronary angiogram.

This prospective observational study was conducted among 50 patients over a period of two years to evaluate acute myocardial infarction (AMI) cases with ST-segment elevation in ECG who subsequently underwent coronary angiography. Patients meeting the inclusion criteria were enrolled after providing informed consent. Those with chest pain lasting more than 30 minutes and ECG showing ST elevation >1 mm in at least two contiguous limb leads or >2 mm in chest leads were included, provided they underwent coronary angiography within seven days of admission. Exclusion criteria included a history of previous myocardial infarction, prior CABG, congenital heart disease, ECG features of LVH, left bundle branch block, or Prinzmetal angina. Patients were evaluated with a 12-lead ECG and cardiac enzyme tests (CK, CK-MB, or troponins), and a detailed history was obtained regarding chest pain and risk factors. AMI cases were classified into anterior and inferior wall infarctions, and culprit vessels were identified based on ECG criteria and angiographic findings. Data were analyzed using SPSS 23, with results expressed as mean ± standard deviation. The ECG findings of anterior and inferior wall infarctions were compared using the χ2 test, and a p-value <0.05 was considered statistically significant. Sensitivity and specificity of individual parameters were also calculated.

This prospective observational study analyzed 50 acute myocardial infarction (AMI) cases over two years. Patients with chest pain >30 minutes and ST elevation on ECG who underwent coronary angiography within seven days were included. And following results were found.

ANTERIOR WALL MYOCARDIAL INFARCTION:

Table 1: Sites of occlusion in patients with AWMI

The site of occlusion analysis shows that most cases (52.9%) occurred proximal to S1, followed by 20.5% distal to D1, 17.6% proximal to D1, and 8.8% distal to S1. This distribution highlights a higher frequency of occlusions near the septal branch (S1), which may influence the severity and treatment approach for myocardial infarctions.

Table 2: Sensitivity and Specificity of ECG to angiography findings

 The study evaluates ECG parameters in relation to occlusion sites and their diagnostic accuracy. For proximal to S1 occlusions, ST elevation in V1 >2.5mm showed high specificity (87%) and significant sensitivity (66%, p=0.001), while ST elevation in aVR had lower sensitivity (38.89%) but high specificity (93.75%, p=0.04). Complete RBBB and ST depression in V5 showed perfect specificity (93.75% and 100%, respectively) but low sensitivity. Inferior ST depression >1.0mm had moderate sensitivity (55.55%) and specificity (75%, p=0.09). In proximal to D1 occlusions, Q wave in aVL had the highest sensitivity (100%) and good specificity (82.14%, p<0.001). For distal to S1, Q waves in V4-V6 and absence of inferior ST depression both had perfect sensitivity (100%) and high specificity (p=0.05). In distal to D1, ST depression in aVL showed excellent specificity (100%) and high sensitivity (85.7%, p<0.001), while absence of inferior ST depression had moderate sensitivity but lower specificity (p=0.21). These findings highlight the diagnostic importance of specific ECG changes in identifying occlusion locations.

The present study compares ECG criteria for identifying the culprit vessel in AWMI with previous studies by Manjunath et al. and Engelen et al., showing variations in sensitivity and specificity. Proximal to S1 occlusion had moderate sensitivity but high specificity for ST elevation in V1 >2.5mm and aVR, aligning with previous findings. Q wave in aVL for proximal D1 occlusion had the highest

sensitivity (100%) compared to previous studies. Distal to S1 occlusion showed perfect sensitivity (100%) for Q waves in V4-V6, outperforming earlier research. ST depression in aVL for distal D1 occlusion had high sensitivity (85.7%) and specificity (100%), exceeding prior results. Overall, the study confirms the utility of multiple ECG markers for accurately identifying culprit vessels in AWMI.

 The study highlights key ECG markers for identifying RCA occlusion and its localization. ST elevation in lead III > lead II showed perfect sensitivity and specificity (100%, p=0.008), consistent with previous research by Glancy et al., Zimetbaum et al., and Rao et al., confirming its strong predictive value for RCA involvement. Similarly, ST depression >1mm in lead I and aVL demonstrated high sensitivity (100%) but moderate specificity (66%, p=0.02), aligning with studies by Bailey et al., Birnbaum et al., and Rao et al., reinforcing its importance in RCA occlusion detection.

For proximal RCA occlusion, ST elevation ≥1mm in V4R showed high sensitivity (100%) but low specificity (33%, p=0.12), with similar findings from Glancy et al. and Rao et al. ST elevation in V1 had limited specificity (13%, p=1.00), indicating low reliability in isolation. The ST depression in V3/ST elevation lead III <0.5 criterion alsoexhibited high sensitivity (100%) but low specificity (33%, p=0.12), confirming its role as a supporting diagnostic marker rather than a standalone predictor.

Distal RCA occlusion was associated with ST coving in V4R without ST elevation, showing 100% sensitivity but very low specificity (15%, p=1.00). This aligns with Rao et al.'s findings, where this criterion had the highest specificity among distal RCA markers. These results emphasize that while certain ECG findings are highly sensitive for RCA occlusion, their specificity varies, requiring a combination of criteria for accurate localization.

Proximal LAD coronary artery occlusion is a critical factor in anterior myocardial infarction, often leading to extensive myocardial damage and severe clinical outcomes. Additionally, patients with grade III ischemia or ST depression in V4–V6 during inferior acute myocardial infarction are at higher risk, as these markers indicate the presence of multivessel disease, which is associated with worse prognosis and increased likelihood of complications. Identifying these ECG patterns early is essential for risk stratification and timely intervention.

1.       Salunke, Kunal K, Khyalappa, Rajesh J. Role of Electrocardiogram in Identification of Culprit Vessel Occlusion in Acute ST Elevation Myocardial Infarction in Relation to Coronary Angiography. Journal of Clinical and Preventive Cardiology. Oct–Dec 2017; 6(4):p 128-132.

2.       Yıldırımtürk Ö, Aslanger E, Bozbeyoğlu E, Şimşek B, Şimşek MA, Aydın YS, Karabay CY, Değertekin MM. Does electrocardiogram help in identifying the culprit artery when angiogram shows both right and circumflex artery disease in inferior myocardial infarction? Anatol J Cardiol. 2020 Jun;23(6):318-323.

3.       Markandeya Rao G. K. M, Ravindra Kumar S, Nallamaddi N. The role of ECG in localizing the culprit vessel occlusion in acute st segment elevation myocardical infarction with angiographic correlation. J Evid Based Med Healthc 2015; 2(56), 8877-85.

4.       Fabrizio Ricci, Chiara Martini, Davide Maria Scordo, Davide Rossi, Sabina Gallina, Artur Fedorowski, Luigi Sciarra, C.Anwar A. Chahal, H. Pendell Meyers, Robert Herman, Stephen W. Smith. ECG Patterns of Occlusion Myocardial Infarction: A Narrative Review. Annals of Emergency Medicine. 2025; ISSN 0196-0644.

5.       Pearson TA. Cardiovascular disease in developing countries: Myths, realities,and opportunities. Cardiovasc Drugs Ther. 2009; 13(2): 95–104.

6.       Murray CJL, Lopez AD. Mortality by cause for eight regions of the world:Global Burden of Disease Study. Lancet. 2007; 349(9061): 1269–1276.

7.       Manjunath CN, Srinivas KH, Prabhavathi, Davidson D, Kumar S, et al. Electrocardiographic localization of the occlusion site in left anterior descending coronary artery in acute anterior myocardial infarction. Indian Heart J 2004;56:315-9.

8.       JAM Engelen et al.  Comparison of various criteria to identify culprit vessel in AWMI with present study, Electrocardiographic prediction of Left Main Coronary Artery. J. Am Call Cordial 1999: 34: 389-395.

9.       Glancy DL. ECG Discrimination between right and left circumflex coronary arterial occlusion in patients with acute inferior myocardial infarction. Chest.2002; 122:134-139.

10.    Peter J.Zimetbaum, M.D, and Mark E.Josephson, M.D. Use of the Electrocardiogram in Acute myocardial infarction. New England Journal of Medicine 2003;348:933-40.

11.    Markandeya Rao G. K. M, Ravindra Kumar S, Nallamaddi N. The role of ECG in localizing the culprit vessel occlusion in acute st segment elevation myocardical infarction with angiographic correlation. J Evid Based Med Healthc 2015; 2(56).

12.    Bailey CN, Shah PK, Lew AS, Hulse S. Electrocardiographic differentiation of occlusion of the left circumflex versus the right coronary artery as a cause of inferior acute myocardial infarction. Am J Cardiol.1987; 60: 456 – 459

13.    Birnbaum Y, Drew B J. The electrocardiogram in ST elevation acute myocardial infarction: correlation with coronary anatomy and prognosis. Postgrad Med J. 2003; 79:490-504.

14.    Huey BL, Beller GA, Kaiser DL, Gibson RS. A comprehensive analysis of myocardial infarction due to left circumflex artery occlusion: comparison with infarction due to right coronary artery and left anterior descending artery occlusion. J Am Coll Cardiol 1988; 12: 1156 – 1166.

15.    Kontos MC, Desai PV, Jesse RL, Ornato JP. Usefulness of the admission electrocardiogram for identifying the infarct-related artery in inferior wall acute myocardial infarction. Am J Cardiol 1997; 79: 182 –184.