A 21-year-old woman presented with recurrent palpitations in the setting of previously documented Tetralogy of Fallot. Primary repair had been performed at the age of 9 years, with requirement for dual-chamber pacemaker implantation in the early postoperative period. Unfortunately, no operative details were obtainable. Transthoracic and transoesophageal echocardiography confirmed the presence of severe RVOT obstruction with peak and mean gradients of 100 and 63 mmHg, respectively, together with trivial pulmonary regurgitation. In addition, moderate right ventricular dilatation with moderate/severe systolic dysfunction and elevated right ventricular systolic pressure (90 mmHg) were found. However, echocardiography was unable to localize the site of the RVOT/PA obstruction ( Fig. 1 , Video 1 ). CCT was carried out with a 64-row multidetector scanner after peripheral vein injection of 90 cc of the non-ionic contrast medium Ioversol (Optiray 320 mg/mL; Tyco Healthcare Canada, Inc., Pointe Claire, QC, Canada) as a bolus dose at the rate of 5 mL/s with retrospective electrocardiogram gating. CCT demonstrated a thickened small RVOT (9 mm) with a dynamic obstruction secondary to a hypertrophied muscle bundle. Additionally, there was a conduit placed between the upper right ventricular body and the normal-calibre right PA, with severe calcification and stenosis. The main PA had an unusual shape and was narrowed at the bifurcation (12 mm), with an enlarged origin of the left PA (25 mm) connected to the native RVOT ( Figs. 2 and 3 ). The origin and course of the coronary arteries were normal. The patient underwent successful conduit excision, resection of the native RVOT muscle bundles, RVOT/proximal main PA pericardial patch, arterioplasty of the distal main PA and the proximal portions of both PA branches and pulmonary valve replacement with a 27 mm mosaic bioprosthetic valve. Surgery was uneventful.
