Case 2
A 11-year-old boy with Ebstein anomaly, who underwent tricuspid valve replacement using a 27 mm St Jude prothesis when he was nine, underwent ablation due to drug resistant atrial flutter. ECG revealed an atrial rate of 250 ms and 4:1 AV conduction. Echocardiography revealed no paravalvular regurgitation from prosthetic valve, thrombosis nor increase in transvalvular mean doppler gradient of the prosthetic valve, with a normal ventricular systolic function. He had history of several CV under medical treatment of amiodarone and propranolol. Since decapolar reference catheter could not be inserted into the coronary sinus, a quadripolar catheter (Esolo FIAB, Italy) was inserted into esophagus as a reference catheter. The EnSiteā„¢ NavX Precision system (St. Jude Medical St. Paul, MN, USA) is used as three dimensional mapping system and Tacticath TM Quartz Contact Force (St. Jude Medical St. Paul, MN, USA) for mapping and ablation procedure. Widespread scar areas were detected in the posterolateral region of right atrium. The patient had three distinctive type of tachycardia with different cycle lengths, two reentries detected involving scar areas in right atrium posterior and superior region. Ablation lines were applied on that region in low voltage scar areas forming isthmuses for the reentries. Since ablation of myocardium under mechanical valve could not be performed due to loss of contact of catheter. CTI dependent flutter could not be accomplished even though ablation line extended beyond mechanical valve. Even though, CTI ablation could not be accomplished, sinus rhythm achieved under medical treatment of flecainide and propranolol and remained for two years after ablation procedure.