CATHETER ABLATION OF ATRIOATRIAL CONDUCTION AS A CURE FOR ATRIAL ARRHYTHMIA AFTER ORTHOTOPIC HEART-TRANSPLANTATION

Objectives. We present three patients in whom atrial arrhythmia was tr eated by ablation of electrical conduction across a surgical suture li ne. Background. Conduction across the suture line separating the donor and native right atria has recently been described after orthotopic h eart transplantation. Methods. Mapping and pacing of both grafted and recipient right atrium was performed to assess the relation between bo th atria and its relevance to clinical arrhythmia, prior to successful radiofrequency at the site of electrical communication. Results. In c ases 1 and 3, atrioatrial conduction was bidirectional. In both, two t ypes of P waves were observed during sinus rhythm. In case 2, conducti on from the recipient to the grafted atrium yielded a very particular surface ECG pattern of atrial extrasystole. The block being unidirecti onal, the recipient atrial sinus rhythm was not perturbed and behaved like an atrial parasystole. Ablation was performed during sinus rhythm in case 1, recipient right atrial pacing in case 2 and grafted right atrial pacing in case 3 at the site with the shortest conduction time to the other tissue. At the successful ablation site multiple componen t potentials were recorded. Respectively, 1, 4 and 2 radiofrequency pu lses were followed by total atrioatrial conduction interruption. No ta chycardia could be induced at the end of the procedure and late follow -up was event free. Conclusions. The existence of arrhythmogenic atrio atrial conduction should be taken into account when evaluating atrial arrhythmias in the transplanted heart because it is potentially curabl e by radiofrequency catheter ablation. (C) 1998 by the American Colleg e of Cardiology.