Significance of ST-segment deviation in lead aVR for prediction of culprit artery and infarct size in acute inferior wall ST-elevation myocardial infarction

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.

The Value of Lead aVR ST Segment Changes in Localizing Culprit Lesion in Acute Inferior Myocardial Infarction and Its Prognostic Impact

BACKGROUND

Identifying infarct-related artery (IRA) in patients with inferior ST elevation myocardial infarction (STEMI) has prognostic and therapeutic benefits.

OBJECTIVES

To differentiate IRA and the location of culprit lesion in inferior STEMI, using ST segment changes in lead aVR.

METHODS

ST segment changes in lead aVR were recorded in 150 patients, admitted with first inferior STEMI. The association of IRA and the location of culprit lesion with ST segment changes in aVR were investigated.

RESULTS

ST elevation ≥ 0.5 mm in lead aVR was present in 17 patients (11.3%), ST depression ≥ 0.5 mm in 74 patients (49.3%) and 59 patients (39.3%) did not have significant ST segment changes. Right coronary artery (RCA) was the IRA in 117 patients (78%) and left circumflex artery (LCX) in 33 patients (22%). Prevalence of RCA involvement as the IRA was different in three study groups (94.1% in ST elevation group, 83.1% in isoelectric group and 70.3% in ST depression group, P = 0.049). Presence of ST elevation had a sensitivity and specificity of 13.68 % and 96.97%, for detecting RCA lesions, respectively. ST depression had 66.67% sensitivity and 55.56% specificity for identifying LCX lesions. Clinical complications were low in our study with no significant difference among patients of three groups.

CONCLUSIONS

Presence of ST elevation is highly suggestive of RCA lesions versus LCX lesions, whereas absence of ST elevation cannot rule out RCA lesions. Presence of ST depression has a moderate sensitivity and specificity for LCX lesions.