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

Purpose: The 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. Methods: Electrocardiogram and cardiac magnetic resonance were studied in 56 patients. Areas involved were related to QRS changes in precordial leads. Results: Significant correlations were found between lateral wall involvement and R waves in V-1 and V-6 (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 V-1 and V-2 (P = 0.001-0.034). Conclusions: Tall and broad R waves in V-1 reflect lateral wall MI, especially in circumflex occlusions.