Standardized patch infundibuloplasty for tetralogy of Fallot.

To preserve right ventricular function after intracardiac repair of tetralogy of Fallot, we developed a standardized patch infundibuloplasty with minimum ventriculotomy and myocardial resection. An experimental study suggested that short and medium-length patch infundibuloplasty, less than 50% of the right ventricular length, did not reduce the right ventricular function. A morphologic study showed that the ratio of the infundibular septal and the right ventricular lengths ranged from 0% to 34% with an average of 14% in 100 cases of tetralogy of Fallot. The optimal infundibuloplasty patch length was determined to be between 30% and 45% of the right ventricular length. The standard formulas for determining minimum (30%) and maximum (45%) patch infundibuloplasty lengths were as follows: 1.28 X body surface area (m2) + 1.10 cm (minimum) and 1.93 X body surface area (m2) + 1.65 cm (maximum). In clinical experience, a patch infundibuloplasty length shorter than 45% of the right ventricular length resulted in an intraoperative right ventricular to systemic arterial pressure ratio of 55% +/- 15% (n = 90).