The electrocardiogram in complete transposition of the great vessels

The electrocardiograms of 53 patients with complete transposition of the great vessels were analyzed. They showed the following: 1. 1. In 88.68 per cent the ÂQRS was located in sextants IV and V of Bayley's triaxial system. 2. 2. The P wave was normal in 41.51 per cent, tall and peaked or notched in 28.30 per cent, peaked in 16.98 per cent, and notched in 13.21 per cent. 3. 3. The P-R interval was normal in 52 patients. It was prolonged in 1 with single ventricle and pulmonary stenosis. 4. 4. An R in Lead aV R was greater than 5 mm., and the R S or R Q ratio was greater than 1.0 in 50 per cent. 5. 5. A Q wave in Leads V 4R and V 1 was present in 13.21 per cent. Both marked right axis deviation and a Q wave in the right precordial leads were absent in patients under 3 months of age. 6. 6. An RSR′ pattern in the right precordial leads was present in 13.21 per cent; an rs, rS, Rs, or RS was present in 66.04 per cent, of which rs alone constituted 54.72 per cent. 7. 7. A low, notched, flat, diphasic, or “juvenile” T wave in the left precordial leads was associated with right ventricular hypertrophy and upright T wave in the right chest leads in 18.87 per cent. 8. 8. Right ventricular hypertrophy (RVH) was diagnosed in 62.26 per cent, left ventricular hypertrophy (LVH) in 15.09 per cent, and combined ventricular hypertrophy (CVH) in 9.43 per cent, and in 13.21 per cent the electrocardiograms were normal. All patients with a “normal” electrocardiogram were under 1 month old. 9. 9. The electrocardiogram in 6 patients with single ventricle showed dominance of the left ventricular pattern. All patients in whom the ÂQRS was in sextants I, II, and VI of Bayley's triaxial system had single ventricle.