The vectorcardiogram in infants undergoing arterial switch repair

The vectorcardiogram in 4 children undergoing the arterial switch repair

Four children with complete transposition (concordant atrioventricular and discordant ventriculo-arterial connections), aged 1.2 to 16.4 years, underwent a delayed repair by the arterial switch procedure from March 1985 to October 1986. Three children had undergone previous atrial diversion repairs in early childhood. Two of these children had developed right ventricular dysfunction with tricuspid incompetence as well as having recurrent and symptomatic supraventricular tachyarrhythmias. They underwent banding of the pulmonary trunk 0.7 and 1 year prior to the final repair. The third child had dynamic obstruction of the left ventricular outflow tract and prior banding was not performed. A fourth child had right ventricular dysfunction on initial assessment in early infancy and then had banding of the pulmonary trunk. Two patients survived the arterial switch operation. Vectorcardiograms were performed on these 4 children before arterial switch repair. The left maximal spatial voltage did not correlate with elevated left to right ventricular pressure ratio at cardiac catheterization before arterial switch repair nor did it relate to survival after operation. The horizontal loop was clockwise in all patients preoperatively. The vectorcardiogram in these children was not a useful indicator that the left ventricle was suitably prepared for the arterial switch repair.