Factors affecting biventricular function following surgical repair of tetralogy of Fallot

Right and left ventricular functions were assessed in children following surgical repair of tetralogy of Fallot. The results were analyzed with regard to the relative contribution of preoperative, perioperative and postoperative factors to postoperative functional abnormalities. Pulmonary regurgination of our Grade 3 or more depressed right and left ventricular ejection fractions and enlarged right ventricular end-diastolic volume. Right and left ventricular ejection fractions in patients with residual right ventricular outflow pressure gradients over 30 mmHg were significantly lower than those in patients with pressure gradients of 30 mmHg or less. The majority of those pressure gradients were at the pulmonary annulus or central pulmonary artery. Right and left ventricular ejection fractions were significantly lower in patients with a preoperative aortic oxygen saturation of less than 80% than in patients with one of 80% or more. The 3 variables of pulmonary regurgitation, residual pulmonary stenosis, preoperative aortic oxygen saturation were statistically independent. Left ventricular ejection fraction and end-diastolic volume correlated with the right ventricular ejection fraction and end-diastolic volume, respectively (r = 0.63, r = 0.68). These results show that severe pulmonary regurgitation, significant annular or central pulmonary stenosis and preoperative hypoxia are major contributing factors to right ventricular dysfunction after surgical repair of tetralogy of Fallot. The postoperative left ventricular dysfunction can be largely attributed to dysfunction of the right ventricle.