Transcatheter creation of a de novo communication across an extracardiac Fontan conduit for catheter ablation of a “left-sided” accessory pathway

Abstract

Extracardiac polytetrafluoroethylene (PTFE) conduits are often used in modified Fontan procedures for separating systemic and pulmonary circulations in morphological and functional single ventricles [1]. However, most arrhythmia substrates of congenital and acquired supraventricular tachycardias will then be located ‘‘left-sided’’ across the extracardiac conduit. Remote magnetic navigation not only may facilitate a retrograde approach, but may also fail to reach the arrhythmia substrate [2]. Hybrid intervention consisting of transcatheter ablation via a sternotomy approach and atriotomy incision [3] as well as catheter ablation via direct transthoracic percutaneous access [4] have been described, but appear to be associated with frequent complications. An antegrade approach via femoral access requires special techniques for traversing the stiff PTFE material, the pericardial space and the atrial muscular wall. This is the first report that describes a modified transseptal puncture technique using no more than mechanical force [5] for successful catheter ablation across an extracardiac PTFE Fontan conduit. A 23-year-old male patient with double-outlet right ventricle, mitral atresia, severe left ventricular hypoplasia, subpulmonary ventricular septal defect, valvular pulmonary stenosis and D-transposition of the great arteries after modified Fontan anastomosis presented with a 15-year history of recurrent supraventricular tachycardia. Bidirectional superior cavopulmonary anastomosis (Glenn) had been performed at the age of 6 years, modified Fontan anastomosis with an extracardiac non-fenestrated 19 mm PTFE conduit connecting the inferior vena cava and the pulmonary arteries 2 years later. Tricuspid valve (TV) repair employing an anuloplasty ring was carried out for tricuspid regurgitation at the age of 17 years. Despite various oral antiarrhythmic medications [propafenone (up to 600 mg per day, 13 mg/kg per day); propafenone (up to 600 mg per day, 13 mg/kg per day) plus bisoprolol (2,5 mg per day) plus digoxin (aiming at serum levels of 1–2 ng/ ml); sotalol (up to 320 mg per day, 5 mg/kg per day); sotalol (160 mg per day) plus digoxin (aiming at serum levels of 1–2 ng/ml)], the patient continued to experience recurrent adenosine-sensitive supraventricular tachycardias (cycle length 340 ms). After discontinuation of antiarrhythmic medication, electrophysiology testing was performed with one steerable quadripolar catheter placed retrograde across the aortic valve in a right ventricular (RV) position and with one steerable decapolar catheter at the junction of the left pulmonary artery and the calcified extracardiac conduit where atrial sensing and pacing was possible. A supraventricular tachycardia (cycle length 350 ms) characteristic for orthodromic atrioventricular reciprocating tachycardia (AVRT) was easily induced by programmed ventricular pacing (Fig. 1a, b). Electroanatomical mapping of earliest retrograde atrial activation during tachycardia was performed using the EnSite Velocity Cardiac Mapping System (EnSite NavX, St. Jude Medical, St. Paul, MN, USA). Using the steerable quadripolar catheter placed retrograde across the aortic valve, the G. Kerst (&) D. Schranz M. B. Gonzalez y Gonzalez Department of Pediatric Cardiology, Pediatric Heart Center Giessen, University Children’s Hospital, Feulgenstr. 10-12, 35392 Giessen, Germany e-mail: gunter.kerst@paediat.med.uni-giessen.de