MAPPING AND RADIOFREQUENCY ABLATION OF INTRAATRIAL REENTRANT TACHYCARDIA AFTER THE SENNING OR MUSTARD PROCEDURE FOR TRANSPOSITION OF THE GREAT-ARTERIES

The Senning and Mustard procedures are often associated with the devel opment of atrial tachyarrhythmias, which may be a cause of sudden deat h, We hypothesized that atrial surgery creates barriers to impulse pro pagation, establishing potential routes for atrial reentry, and that m apping combined with knowledge of the surgical anatomy could identify zones that are critical to the tachycardia to be targeted for radiofre quency catheter ablation, Patients underwent mapping to identify early sites of atrial activation that were related to anatomic or surgicall y created obstacles, with confirmation by pacing to demonstrate concea led entrainment, Radiofrequency lesions were placed to connect these o bstacles, while observing for tachycardia termination. Thirteen tachyc ardias were attempted in 10 patients, 10 successfully, Three patients held 2 distinct tachycardias. Successful sites were in right atrial ti ssue, although in many, a retrograde approach to the pulmonary venous atrium was necessary. Ablation of the clinically documented tachycardi a was successful in 9 of 10 patients, The most common successful site was the region of the coronary sinus mouth, approached antegrade or re trograde. Ablation of intraatrial reentrant tachycardias after the Sen ning or Mustard procedure is feasible using concealed entrainment mapp ing techniques, bur requires a detailed knowledge of the individual su rgical anatomy and the ability to approach the pulmonary venous atrium , Radiofrequency ablation offers significant advantages over other man agement modalities in this patient group.