Vectorcardiographic Residua of Inferior Infarction

Abstract

Seventy-eight patients with well-documented inferior infarction were studied by the Frank vectorcardiographic technic. The commonest residual was superior and leftward orientation of the early forces that moved clockwise in the frontal projection. Quantitative data on the duration, magnitude, and leftward sweep of these forces are presented. In 52 cases, the entire frontal loop was clockwise. When sagittal loop reversal, partial or total, ocurred in this group, a high correlation with associated anterior infarction or left ventricular enlargement was noted. In 24 patients, the returning frontal limb was deformed due to upward bowing. When anterior forces were well preserved in the presence of this deformity, a characteristic "pollywog" shape in the sagittal loop resulted. Conduction defects were twice as common in the cases with mid-loop frontal deformity as in the cases without such defects. Anterior forces of prominent voltage and prolonged duration were noted in 19 cases. Quantitative data on these cases, presumably reflecting associated posterior infarction, are presented. The vectorcardiographic residua of inferior infarction may be classified according to rotational characteristics of the frontal and sagital loops. Classification may be of value in providing clues to associated anterior disease, left ventricular enlargement, and conduction defect.