Histopathological changes of right ventricle outflow tract myocardium in relation to age in tetralogy of Fallot and its relation to clinical outcome

Background: Right ventricle outflow tract myocardium in tetralogy of Fallot reflects the effect of hemodynamic stresses on right ventricle muscle and correlates with clinical right ventricle dysfunction. It may be a useful adjunct in determining the time for intracardiac repair and predicting the clinical outcome. Methods: Septal and parietal bands of infundibular septum and obstructing muscle bands were excised in 48 patients undergoing intracardiac repair for tetralogy of Fallot. Microscopic study of histopathological changes in resected muscle bands was done. Post operative 2D echocardiography and tissue doppler imaging were done at the end of first and third month evaluating the right ventricular function. Results: Moderate myocardial fibrosis was seen in 42.9% (12/28) patients with age >5 years compared to 37.5% (6/16) patients with age between 1-5 years and 0% patients with age