A Prominent R Wave in V(1) but not in V(2) Is a Specific Sign of a Large Lateral Transmural Infarction

INTRODUCTION AND OBJECTIVES:In the absence of right ventricular hypertrophy or bundle-branch block, a prominent R wave in V(1) or V(2) is considered to reflect a lateral myocardial infarction. We investigated the differences in infarct location, size and transmural extent between patients with prominent R wave in V(1) and those with prominent R wave in V(2). METHODS: We studied 50 patients with a previous first infarction involving left ventricular inferior and/or lateral wall at contrast-enhanced magnetic resonance. RESULTS: A prominent R wave in V(1) was present in 8 patients (16%), in V(2) in 23 (46%). At magnetic resonance, the infarction involved the inferior wall in 11 patients (22%), the lateral wall in 6 (12%), and both walls in 33 patients (66%). The sensitivity of a prominent R wave in V(1) in detecting a lateral infarction was low (17.9%), while the specificity was high (90.9%). The sensitivity and specificity of a prominent R wave in V(2) were 46.2% and 54.5%, respectively. In patients with a prominent R wave in V(1), infarct size and lateral and transmural extent were greater than in patients without this pattern (P<.005, <.001, and <.05, respectively); conversely, infarct size and transmural extent in the inferior wall and in its basal-posterior segment were not significantly different. In patients with a prominent R wave in V(2), infarct size, lateral and transmural extent were not different from patients without this pattern. CONCLUSIONS: Only a prominent R wave in V(1) is a specific sign of large and transmural lateral infarction.