Echocardiographic study of right and left ventricular dimension and left ventricular function in patients with tetralogy of Fallot before and after surgery

Abstract

Right and left ventricular dimensions and function were determined by one-dimensional echocardiography in patients with tetralogy of Fallot before and after corrective surgery. Thirty-five children (mean age: 5.9 years) were examined; 5 of them died immediately after operation; 5 had palliative operations only. The remaining 25 had repeat echocardiography 2 to 4 and/or 8 weeks after total correction. Compared with normal values, preoperative left ventricular dimensions were smaller than expected for body surface area (mean = 85.4% +/- 1.9 SEM, range 65 to 105% of normal); 21 values were below the 5th centile. Postoperatively, left ventricular dimensions increased significantly and reached normal values in most cases (mean = 103.2 +/- 2.0% SEM, range 81 to 121%). The main increase took place in the first 4 weeks (P less than 0.001; mean difference 0.7 +/- 0.14 cm). The 5 children who died after operation had smaller left ventricular dimensions than the survivors (P less than 0.01). Left ventricular function was evaluated by measuring mean circumferential fibre shortening, per cent shortening, and ejection fraction; they were normal in most patients and diminished only insignificantly after corrective surgery. Right ventricular dimensions were increased preoperatively but decreased significantly (P less than 0.001) postoperatively. Septal movement was normal in direction and excessive in displacement in most patients before operation; immediately after operation it became flat or showed paradoxical motion. Two months after operation 50 per cent of the children showed a return to normal septal movement. Early appearance of normal septal movement could be related to the presence of significant pulmonary stenosis. It is concluded that a high percentage of patients with tetralogy of Fallot have underdeveloped but normally functioning left ventricles which adapt well to the new postoperative state.