Assessment of validity of the ‘Culprit Score’ for predicting the culprit lesion in patients with acute inferior wall myocardial infarction

INTRODUCTION: Many electrocardiographic criteria have been developed to determine the infarct-related artery in acute inferior wall myocardial infarction. The aim of this study was to test the commonly used criteria and devise a simplified score to further improve the diagnostic accuracy. MATERIALS AND METHODS: From 2011 to 2013, 100 patients with acute inferior wall myocardial infarction were recruited for electrocardiographic and angiographic analyses. RESULTS: The mean age of the patients was 65 ± 12 years with 74% of patients being male. In our study population, significantly more ST-segment depression was seen in lead aVL and ST elevation in lead III in those with right coronary artery (RCA) occlusions. In left circumflex artery (LCX) occlusions, significantly more ST depression was seen in leads V1–3 (most significantly in lead V2) and ST elevation in lead II. In addition, more prominent ST depression was seen in lead aVL and ST elevation in V1 in proximal RCA occlusions. Based on the findings, we devised a score named Culprit Score, which was defined as [II − V2/III + V1 − aVL]. The sensitivity and specificity of Culprit Score ≤0.5 to predict proximal RCA occlusions; 0.5 to ≤1.5 to predict distal RCA occlusions; and score >1.5 to predict LCX occlusions were 85% and 85%; 80% and 86%; and 80% and 94%, respectively. Similarly, the negative predictive value was more than 80%. CONCLUSION: The Culprit Score was found to have high specificity and negative predictive value to identify the infarct-related artery in inferior wall myocardial infarction.