Persistent Truncus Arteriosus

An Electrovectorcardiographic Study in 14 Infants

¹ Department of Pediatrics and the Human Development Center, University of Florida College of Medicine, Gainesville, Fla.

The electrocardiograms and vectorcardiograms in 14 infants with type I and II persistent truncus arteriosus have been analyzed in detail. Each case still had markedly increased pulmonary flow and signs of congestive heart failure. In many respects the clinical findings resembled other forms of large left-to-right shunts below the atrioventricular valve. Since a corrective procedure has been devised for persistent truncus arteriosus, it is imperative that the diagnosis be suspected in any infant with heart failure secondary to congenital heart disease. The common electrovectorcardiographic findings, showed that: (a) abnormal P waves were a constant feature and left or biatrial enlargement was more common than pure right atrial enlargement; (b) the mean QRS axis in the frontal plane did not show extreme variation. All of them fell into a relatively narrow range (+55° to +130°); and more interestingly, the mean QRS vector in each patient was within the normal limits for age; (c) combined ventricular hypertrophy was the most common electrovectorcardiographic pattern (70 per cent of the cases). An abnormally small, biphasic or negative T wave in V₆ was also a frequent finding. Thus, the electrovectorcardiogram in persisent truncus arteriosus in infants with increased pulmonary flow has a more consistent picture than previously described.