Evaluation of the electrocardiogram in identifying and quantifying lateral involvement in nonanterior wall infarction using cardiovascular magnetic resonance imaging

PurposeThe objective of this study was to assess the involvement and extent of lateral wall myocardial infarction (MI) in patients with a first nonanterior wall MI, as reflected by changes in precordial leads. Delayed enhancement cardiac magnetic resonance imaging was used as a gold standard to localize and quantify myocardial scar tissue.MethodsElectrocardiogram and cardiac magnetic resonance were studied in 56 patients. Areas involved were related to QRS changes in precordial leads.ResultsSignificant correlations were found between lateral wall involvement and R waves in V1 and V6 (P = 0.009-0.022). For patients with circumflex branch occlusions, the MI size of the apical and lateral segments correlated strongly with the characteristics of R waves in V1 and V2 (P = 0.001-0.034).ConclusionsTall and broad R waves in V1 reflect lateral wall MI, especially in circumflex occlusions.