High density mapping of recurrent right atrial flutter in a biatrial orthotopic heart transplant recipient

Background: Atrial flutter in heart transplant recipients can vary from typical cavotricuspid isthmus dependent (CTI) flutter to scar related flutter with complex circuits Objective: We describe a case of typical right atrio-tricuspid flutter in a biatrial heart transplant patient using highdensity mapping and describe neo-anastomotic connections between donor and recipient atrium. Methods: N/A. Results: A 65-year-old female with ischemic cardiomyopathy status post biatrial heart transplant (1997), dual chamber pacemaker (2001) and CTI ablation in year 2003 was evaluated for symptomatic atrial flutter (Fig. A). High density (∼ 75,000) activation mapping during tachycardia (cycle length 240 ms) with ORION® basket catheter showed a counterclockwise reentrant circuit involving the donor atriotricuspid isthmus (Fig. B). Anastomosis line was clearly defined and conduction into the recipient atrium was noted at the superior-lateral rightatrium. Cathetermanipulation in recipient right atrium led to fast flutter/fibrillation in the recipient atrium which continued despite termination of donor flutter during ablation in the atrio-tricuspid isthmus (Fig. C). Further mapping showed unidirectional conduction into the recipient atrium (Fig. D). Patient has remained arrhythmia free for a year now post ablation. Conclusion: Typical rightatrial flutter can recur years after ablation in hearttransplant patient involving atrio-tricuspid isthmus and high-density mapping using basket catheter is successful indefining the reentrant circuit. Electrical conduction channels can develop between recipient and donor atria which may or may not participate in arrhythmogenesis