The vectorcardiogram in complete transposition of the great arteries: Correlation with anatomic and hemodynamic findings and calculated left ventricular mass

Abstract

The Frank vectorcardiograms of 28 patients with complete transposition were reviewed. It was found that the direction of inscription of the horizontal plane loop was a reliable predictor of left ventricular pressure in these patients. Patients with intact ventricular septum and a left ventricular peak systolic pressure of less than one-half systemic were found to have clockwise horizontal plane QRS vector loops directed predominatly to the right and anterior. Patients with systemic pressure in the left ventricle as a result of a large ventricular septal defect, or in one case severe pulmonary stenosis with intact ventricular septum, were found to have counterclockwise or figure-of-eight horizontal plane loops. Therefore, a clockwise horizontal plane loop is good evidence that left ventricular pressure is low and that the patient does not have an associated large ventricular septal defect, severe pulmonary stenosis, or severe pulmonary vascular disease. In patients with counterclockwise or figure-of-eight horizontal plane loops (systemic pressure in the left ventricle) the vectorcardiogram was not helpful in separating patients with large pulmonary flow from those with decreased pulmonary flow secondary to severe pulmonary stenosis, a pulmonary artery band, or severe pulmonary vascular disease.