The predictive value of aVR in determining the infarct related artery during primary percutaneous coronary intervention.

Background: Isolation of infract related artery and timely revascularisation remains vital in the setting of primary percutaneous coronary intervention.

Objectives: To analyse the predictive value of ST-T changes in lead aVR in inferior myocardial infarction in terms of prognosis and timely risk stratification.

Methods: We conducted a prospective analysis of acute inferior wall myocardial infarction patients. One hundred patients were categorised into two groups according to the culprit artery: group I, right coronary artery (RCA) and group II, left circumflex coronary artery (LCX), with 50 patients in each group. A comparative study was performed between the two groups, comprising the following data outputs: electrocardiogram (ECG) changes that could help determine the culprit artery, cardiac enzyme levels, echocardiographic findings, coronary angiography findings and in-hospital complications. The same patients were divided into two groups according to the presence or absence of 1 mm ST depression in lead aVR. A comparison analysis was performed between the two groups including: cardiac enzyme levels, echocardiographic findings, coronary angiography findings and in-hospital complications.

Results: ST depression in aVR ≥ 1 mm predicted the LCX as a culprit artery with sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) recorded at 66%, 84%, 80.5% and 71.2%, respectively. Also, patients with ST depression in aVR ≥ 1 mm showed significantly higher cardiac enzyme levels, indicating larger infarct size, with mean peak creatinine kinase (CK) = 1560 (1057-2375) IU/L versus 970 (613-1683) IU/L, (P value = 0.014), lower ejection fraction (Ef) with mean Ef = 47.93 ± 8.04 versus 54.66 ± 6.52, (P value < 0.001) and more significant mitral regurgitation: 17 (41.5%) patients versus 11 (18.6%) patients (P value = 0.012). Regarding in-hospital complications, there were no significant differences.

Conclusions: ST depression of >1 mm in lead aVR predicts LCX as the infarct related artery and is a predictor of poor outcome in patients with inferior myocardial infarction.