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

•ST-segment elevation in V6 in the acute phase of non-anterior myocardial infarction predicts lateral involvement as expressed by the R/S ratio in V1 and Q-waves in V6 in the post reperfusion phase.•In lead I ST-segment deviation predicts lateral involvement being correlated to height and surface of R in V1 and Q-waves in V6.•A small group of Cx occluded patients (n = 10) showed a high correlation between ST-segment elevation in V6 with R/S ratio in V1. These findings suggest further research in this group.•Lead V2 is no indicator of lateral involvement as expressed by QRS changes in V1 and V6 in the post reperfusion phase of non-anterior myocardial infarction.

PurposeRecent research has established that a tall R-wave in V1 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.MethodsECGs of 69 patients were analyzed. ST-segment changes in representative leads for lateral wall infarction such as V1, V2, V6 and I were correlated with the extent of QRS-wave changes in V1 and V6.ResultsST-segment elevation in V6 showed correlations with R/S ratio in V1 (r = 0.802, B = 0.440, P = < 0.001) and with the depth of Q-waves in V6 (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 V1 (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 V6 (r = 0.538, B = 0.114, P = 0.006). ST-segment changes in V2 showed no significant correlation with either R- or Q-wave measurements.ConclusionsST-segment elevation in V6 in the acute phase of non-anterior MI predicts lateral involvement as expressed by the R/S ratio in V1 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 V1 and Q-waves in V6.