Electrocardiographic prediction of lateral involvement in acute non-anterior wall myocardial infarction

Purpose: Recent research has established that a tall R-wave in VI indicates lateral wall involvement in non-anterior wall myocardial infarction (MI). The objective of this study was to assess the value of the admission electrocardiogram (ECG) to predict R-waves and consequently lateral wall damage in the late phase of non-anterior MI. Methods: ECGs of 69 patients were analyzed. ST-segment changes in representative leads for lateral wall infarction such as V-1, V-2, V-6 and I were correlated with the extent of QRS-wave changes in V-1 and V6. Results: ST-segment elevation in V-6 showed correlations with R/S ratio in V-1 (r = 0.802, B = 0.440, P = <0.001) and with the depth of Q-waves in V-6 (r = 0.671, B = 0.441, P = 0.007). This correlation was higher in a small subgroup where the left circumflex branch (Cx) was the culprit vessel (r = 0.888, B = 1.469 and P = 0.018). ST-segment depression in lead I correlated with the height of R and the surface of R in V, (height times width of R) (r = 0.542, B = -0.150, P = 0.005 and r = 0.538, B = -0.153, P = 0.005 respectively), especially in the subgroup without proximal occlusions of RCA (r = 0.711 and r = 0.699). ST-segment depression in lead I also predicted Q-waves in V-6 (r = 0.538, B = 0.114, P = 0.006). ST-segment changes in V-2 showed no significant correlation with either R- or Q-wave measurements. Conclusions: ST-segment elevation in V6 in the acute phase of non-anterior MI predicts lateral involvement as expressed by the R/S ratio in VI in the post reperfusion phase. A subgroup with Cx occlusion showed especially strong correlations, although the size of the group was small. In lead I ST-segment depression is correlated to height and surface of R in V-1 and Q-waves in V-6. (C) 2015 Elsevier Inc. All rights reserved.