Abstract

CASTILLO COSTA, Yanina B. et al. Importance of AVR Lead for the Identification of the Infarct-Related Artery in Inferior Myocardial Infarction. Rev. argent. cardiol. [online]. 2006, vol.74, n.1, pp.28-34. ISSN 1850-3748.

The ECG is the simplest method to diagnose an inferior myocardial infarction (infAMI); however, the ECG is less accurate for the identification of the culprit vessel. Objective We had two main objectives, 1) to assess ST segment changes in aVR lead as a predictor of occlusion of right coronary artery (RCA) or left circumflex artery (CX) and 2.) to determine the value of aVR changes in addition to the classic ECG criteria. Research Design and Methods Sixty five patients (pts) with infAMI submitted for coronary catheterization during CCU stay were included. Classic ECG criteria as well as ST segment shifts in aVR lead (↑ST ≥1mm, ↓ST ≥1mm or isoelectric ST (isoST) measured 0.08 sec from the J point were analyzed. Sensitivity (S), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and likelihood ratio (LR) were calculated. The aVR changes were included in a multivariate analysis in order to determine their independent predictive capacity in addition to the classic ECG changes. Results RCA was the culprit vessel in 47 pts (72%) and CX in 18 pts (28%). Classic ECG signs-RCA: ↑STD3/D2 ≥ 1 in 52 pts (91.5%; p = 0.001) and ↓STD1-aVL ≥ 1mm in 34 pts (61%; p< 0.05); CX: ↑STD2/D3 > 1 in 13 pts (50%; p = 0.001) and ↑STV5-V6 ≥ 1 mm in 12 pts (44%; p< 0.001). aVR lead-RCA: ↑ST or isoST in 46 pts (81%; p< 0.001); CX: ↓ST ≥ 1mm in 19 pts (56%; p< 0.01). In the multivariate analysis ↑ST or isoST in aVR lead were predictors for RCA (OR - 95%CI: 4.7 [1.1-19.8]; p = 0.03) whereas ↓ST aVR was a marker for CX. A diagnostic algorithm for culprit RCA was proposed where aVR changes evidenced an additive value to the classic EKG changes: ↑ST or isoST in aVR (PPV 94%; LR+:2). Conclusion During the course of an inferior myocardial infarction, aVR lead analysis seemed to be a useful tool for the identification of the culprit vessel, rendering valuable diagnostic information in addition to the classic ECG signs.

Keywords : Ischemic heart disease; Myocardial infarction; Electrocardiography; Diagnosis.

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