Impact of arrhythmia circuit cryoablation during fontan conversion for refractory atrial tachycardia

Refractory atrial arrhythmias in late postoperative Fontan patients are usu ally associated with residual hemodynamic abnormalities and result in signi ficant morbidity and mortality. Surgical revision of the Fontan anastomosis may improve hemodynamics without eliminating tachycardia. This study sough t to assess the impact of surgical cryoablation of the arrhythmia circuit a t the time of Fontan conversion on the clinical recurrence of tachycardia. Sixteen consecutive atriopulmonary Fontan patients with refractory atrial a rrhythmias underwent surgical conversion to lateral tunnel total cavopulmon ary anastomosis (15) or Fontan revision (1 patient). The initial 4 patients underwent Fontan conversions alone, without specific arrhythmia surgery. T he subsequent 12 patients underwent electrophysiologically guided cryoablat ion of the tachycardia circuits at the time of surgical conversion. The mea n age at Fontan revision was 15.6 +/- 3.8 years. Cryoablation was directed to 3 identified major tachycardia circuits: the inferomedial right atrium, the superior rim of the prior atrial septal defect patch, and along the lat eral right atrial wall. Transmural antitachycardia pacemakers were implante d in 11 of the 16 patients. There was no surgical mortality in either group , and all patients improved in functional classification. All patients not undergoing cryoablation experienced recurrent symptomatic tachycardia requi ring antiarrhythmic therapy (median follow-up, 54 months) versus 2 of 12 pa tients receiving cryoablation (median follow-up, 25 months; p <0.02). Thus, surgical cryoablation of the arrhythmia circuit at the time of Fontan conv ersion is highly effective in the management of refractory atrial arrhythmi as, and is superior to Fontan conversion alone. (C) 1999 by Excerpta Medica , Inc.