Directional analysis of the 12-lead electrocardiogram

Describes a method whereby one can calculate the direction of the instantaneous vectors of the heart's electrical forces using standard digital electrocardiographic (EKG) data. Using this method, the authors developed criteria for healed inferior myocardial infarction (IMI) that performed better than criteria using the traditional parameters of the durations and amplitudes of Q waves in Lead AVF (Specificity/Sensitivity(%)=95/75, 92/61, and 95/64 respectively). In contrast to the directions of the forces of depolarization, the magnitudes of these forces did not discriminate between the normals and the patients with healed IMI. The method permits one to study prospectively and retrospectively the separate effects of direction and magnitude of the electrical forces recorded by the EKG. The calculations needed to apply the method can be performed in the EKG machines themselves by modifying their diagnostic algorithms.