Examined was the effect of surgical technique, particularly the insertion of a transannular patch, on right ventricular diastolic function, and the relationship of forward flow in the pulmonary arteries during late diastole to right ventricular diastolic function in patients with tetralogy of Fallot. Transtricuspid, superior caval venous and pulmonary arterial Doppler spectrals were obtained and compared between 44 patients who had been repaired with a transannular patch; 14 patients who had been repaired with muscular resection and/or pulmonary valvotomy; six who had been repaired with an infundubular patch; and 32 normal children. The velocities of forward flow during late diastole in the pulmonary arteries of normal children ranged from 19.8 to 29.4 cm s(-1) (mean 24.9 +/- 2.8 cm s(-1)) throughout the respiratory cycle. Restrictive right ventricular physiology, defined on the basis of increased forward flow in the pulmonary arteries during late diastole (> 30 cm s(-1)) was present in 25 (57%) of 44 patients with tetralogy of Fallot repaired using a transannular patch. Right ventricular volume was 50.1 +/- 23.7 cm(3) in patients with a restrictive right ventricle and 64.9 +/- 21.4 cm(3) in patients in whom the ventricle was non-restrictive (p < 0.03). QRS duration was 140 +/- 18 and 156 +/- 24 ms in patients with restrictive and non-restrictive right ventricular physiology respectively (p < 0.003). Restrictive physiology was not encountered in patients with tetralogy in whom the pulmonary valve had been preserved. It is concluded that right ventricular restriction is present in many patients with tetralogy of Fallot at mid-term follow-up subsequent to repair using a 'transannular' patch. Restriction is associated with smaller right ventricular size and less prolongation of the QRS complex.