Predictive value of ST-T change of avR lead in detection of coronary artery involvement Inferior MI patients

¯Abstract Background: In inferior MI, both circumflex (CX) and Right coronary artery (RCA) can be involved. Application of noninvasive paramedical evaluations in predicting of such events is considered to be worthwhile. Objective: Detection of coronary artery (RCA or CX) involvement in inferior myocardial infarction based on avR change. Methods: In 100 patients with inferior MI, 12-lead standard ECG was recorded in first 6 hours and ST-T change of avR evaluated. T-P segment was considered as isoelectric line. Data were analyzed using SPSS-12 and the sensitivity, specificity, positive and negative predictive values evaluated. Findings: RCA disease was seen in 72 patients and CX in 28. Isoelectric ST, ST depression and ST elevation in avR were seen in 61, 22 and 17 patients, respectively. Positive predictive value (PPV) of isoelectric ST for RCA disease was 78.7% compared with 21.3% for CX. PPV of ST elevation for RCA and CX diseases were 70.6% and 29.4%, respectively. PPP of ST depression for RCA disease was 54.5% compared to 45.5% for CX. Conclusion: Regarding the higher PPV of isoelectric ST, clinicians are suggested to employ this criterion in addition to other findings for RCA involvement prior to invasive procedure.