Successful Catheter Ablation of Right Atrial Tachycardia After Bilateral Lung Transplantation

A woman underwent bilateral lung transplantation for pulmonary fibrosis in June of 2013. The early postoperative period was complicated by continuous atrial arrhythmias that proved unresponsive to antiarrhythmic agents (propafenon and bisoprolol). Therefore, in February 2014, we performed an electrophysiological study after adequate antibiotic and antimycotic prophylaxis. During the procedure, the clinical tachycardia was easily inducible with burst atrial pacing and programmed atrial extrastimuli. Tachycardia cycle length varied between 380 ms and 420 ms, and A-A-V response after ventricular burst pacing suggested atrial tachycardia. Entrainment mapping from the area of early activation failed to demonstrate reentry as the underlying mechanism of the tachycardia, thus ectopic atrial tachycardia was diagnosed. Electroanatomical mapping was performedwith ENSITENavX system (Endocardial Solutions Inc.) during ongoing arrhythmia (Figure 1). Activation map showed that earliest activation was in the right atrium, corresponding to a scar of the extracorporeal membrane oxigenator (ECMO) cannula during lung transplantation. To avoid paralysis of the diaphragm, we paced the high right atrial regionwith high energy to demonstrate and mark the location of right phrenic nerve. Subsequently, we performed RF ablation with 3.5 mm irrigated tip catheter (AlCath Flux Blue G eXtra) using 40 W energy and 43°C temperature limit. After the application of one RF ablation at the site of earliest activation (ablation time 46 seconds), the arrhythmia stopped immediately and was no longer inducible even after administration of isoproterenol. The total procedure time was 75 minutes with a fluoroscopy time of 2.3 minutes. No procedural complications occurred. Outpatient visits