The electrocardiogram and vectorcardiogram in ventricular septal defect∗

Abstract

1.1. The electrocardiogram and vectorcardiogram in ventricular septal defect may be normal or show variable degrees of left or right ventricular hypertrophy or of combined ventricular hypertrophy. The changes depend on the size of the defect, the magnitude of the left-to-right shunt, the severity of the pulmonary hypertension and infundibular hypertrophy of the right ventricle.2.2. A normal electrocardiogram and vectorcardiogram generally indicate a small defect and a small left-to-right shunt.3.3. Left ventricular overloading or hypertrophy indicates a moderate-sized to large leftto-right shunt.4.4. Combined ventricular hypertrophy is observed in moderate to severe defects with large left-to-right shunts, with or without pulmonary hypertension.5.5. Electrocardiographic and vectorcardiographic signs of pure right ventricular hypertrophy are uncommon and when present indicate either severe pulmonary hypertension or infundibular stenosis of the right ventricle due to hypertrophy of the crista. Increasing signs of right ventricular hypertrophy suggest increasing right ventricular hypertension due to one of these two factors.6.6. The electrocardiogram and vectorcardiogram can aid in the differentiation of ventricular septal defect from atrial septal defect, pulmonary stenosis, patent ductus arteriosus, common A-V canal, tetralogy of Fallot and Eisenmenger's complex.