Background: The outcome of patients with inferoposterior myocardial infarction (MI) due to occlusion of right coronary artery (RCA) depends mainly on the location of occlusion (distal vs. proximal). The aim of this study was to evaluate the value of new ECG criteria: the sum of ST depression in I and VL leads and ST changes in V1 lead to predict the location of RCA occlusion in the case of an inferoposterior MI.
Methods: The ECG and angiographical findings of 50 patients with acute inferoposterior MI due to RCA occlusion were analyzed. The value of new criteria was studied alone and in combination to predict proximal versus distal RCA occlusion and compared with previously described criterion based only on ST changes in VL.
Results: Isoelectric or elevated ST in V1 allowed predicting proximal RCA occlusion with 70% sensitivity and 87% specificity with high positive and negative predictive value (87% and 71%, respectively). The new criterion of the sum of ST depression in I and VL >or= 5.5 mm compared to the criterion based only on ST depression in VL was also more specific (91% vs. 72%) for proximal RCA occlusion with better positive and negative predictive values.
Conclusions: The new criterion based on the ST changes in V1 lead is highly accurate in detecting the location of occlusion in the RCA compared to the criteria based only on ST changes in lateral leads. The use of this criterion might increase the accuracy of ECG-based identification of myocardial involvement in acute inferoposterior MI.