Vectorcardiographic criteria for acute right ventricular infarction.

Based on serial vectorcardiographic and cardiac scintigraphic studies of 62 patients with acute myocardial infarction, we propose vectorcardiographic criteria for the diagnosis of acute right ventricular infarction. These criteria are: (1) the direction of the maximal spatial ST vector points either to the right-anterior-inferior or to the right-posterior-inferior octant, and (2) the magnitude of the projection of the maximal spatial ST vector is greater than or equal to 0.15 mV in the horizontal plane. By using these criteria correlated with scintigraphic results, 92% sensitivity was achieved together with 98% specificity; the Kappa statistic was 0.90. In patients with acute inferior and right ventricular infarction, the serial maximal spatial ST vector swung to-and-fro like a 'tug of war' between right-anterior-inferior and right-posterior-inferior octants during the acute stage. In patients with acute inferior-posterior and right ventricular infarction, the serial maximal spatial ST vector pointed to the right-posterior-inferior octant during the whole course of the acute stage. Failure to recognize this electrical phenomenon may make the clinician inaccurate when judging the clinical course of acute right ventricular infarction or over-estimate the result of therapeutic intervention.