Abstract 1733: Complete Ablation of Typical Atrial Flutter in Patients with Corrected Congenital Heart Defects: “Non-Traditional” Access to the Surgically Excluded Cavotricuspid Isthmus

Abstract

Background: Although multiple macroreentrant atrial flutters are seen in postoperative patients with congenital heart disease, cavotricuspid isthmus (CVTI) dependent flutter remains a fairly common arrhythmia in this group. When a Fontan or atrial switch (Mustard/Senning) type of procedure is performed, a portion of the CVTI is excluded from catheter access obtainable via a systemic venous route. We evaluated different techniques to access this excluded portion and completely ablate CVTI dependent flutter. Methods/Results: Between 1990 and 2007, 140 patients with surgically corrected congenital heart disease underwent an ablation procedure at our institution. Their records were reviewed to identify those with prior Fontan or atrial switch procedure who had documented CVTI dependent flutter requiring ablation. Data collected included methods of catheter access, circuits observed or induced, the location and number of ablation lines, immediate and long-term success, and complications. Results: Sixteen patients were identified (14, Fontan; 2, Mustard). In 12/16 (75%) patients bidirectional block of CVTI dependent flutter could not be achieved by right atrial (venous approach) ablation alone. In 7 of those, the excluded portion of the CVTI was targeted for ablation. This was accomplished by a retrograde transaortic approach via an interventricular communication then through the right atrioventricular valve (5 patients). Another retrograde transaortic approach was used with the catheter crossing the left atrioventricular valve then an atrial septal communication (one patient). A third approach involved an antegrade transconduit puncture (one patient). In all 7 patients, successful ablation of CVTI dependent flutter with bidirectional block was achieved. Post-procedure, one patient had temporary AV block requiring pacemaker placement. Follow-up was available on 4/7 patients (3 to 22 months, mean 10 months) with no documented recurrence of their CVTI dependent flutter. Conclusion: Even when surgical procedures exclude a portion of the CVTI, complete ablation for typical atrial flutter with resulting bidirectional block can be achieved via “non-traditional” approaches targeting the surgically excluded arrhythmogenic tissue.