Aims To evaluate the effectiveness and safety of cryoballoon ablation (CBA) compared with radiofrequency ablation (RFA) for symptomatic paroxysmal or drug-refractory persistent atrial fibrillation (AF). Methods and results Prospective cluster cohort study in experienced CBA and RFA centres. Primary endpoint was ‘atrial arrhythmia recurrence’, secondary endpoints were as follows: procedural results, safety, and clinical course. A total of 4189 patients were included: CBA 2329 (55.6%) and RFA 1860 (44.4%). Cryoballoon ablation population was younger, with fewer comorbidities. Procedure time was longer in the RFA group (P = 0.01). Radiation exposure was 2487 (CBA) and 1792 cGycm2 (RFA) (P < 0.001). Follow-up duration was 441 (CBA) and 511 days (RFA) (P < 0.0001). Primary endpoint occurred in 30.7% (CBA) and 39.4% patients (RFA) [adjusted hazard ratio (adjHR) 0.85, 95% confidence interval (CI) 0.70–1.04; P = 0.12). In paroxysmal AF, CBA resulted in a lower risk of recurrence (adjHR 0.80, 95% CI 0.64–0.99; P = 0.047). In persistent AF, the primary outcome was not different between groups. Major adverse cardiovascular and cerebrovascular event rates were 1.0% (CBA) and 2.8% (RFA) (adjHR 0.53, 95% CI 0.26–1.10; P = 0.088). Re-ablations (adjHR 0.46, 95% CI 0.34–0.61; P < 0.0001) and adverse events during follow-up (adjHR 0.64, 95% CI 0.48–0.88; P = 0.005) were less common after CBA. Higher rehospitalization rates with RFA were caused by re-ablations. Conclusions The primary endpoint did not differ between CBA and RFA. Cryoballoon ablation was completed rapidly; the radiation exposure was greater. Rehospitalization due to re-ablations and adverse events during follow-up were observed significantly less frequently after CBA than after RFA. Subgroup analysis suggested a lower risk of recurrence after CBA in paroxysmal AF. Trial Registration ClinicalTrials.gov (NCT01360008), https://clinicaltrials.gov/ct2/show/NCT01360008.

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Aims Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management and outcome are sparse. Methods and results This international multicenter registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553,729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed at 214 centers in 35 countries. In 78 centers 138 patients (0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (p<0.0001)) were diagnosed with an oesophageal fistula. Periprocedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8%, and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) (odds ratio 7.463 (2.414, 23.072) p<0.001). Conclusions Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.

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M ustard repair for complete dextrotransposition of the great arteries (D-TGA) is associated with a 10% incidence of late recurrent atrial tachycardias.1 Most of these tachycardias (localized, as they are, in the pulmonary venous atrium) are not directly accessible for ablation and require either a retrograde approach or a transseptal approach. [2][3][4] We present a case of successful radiofrequency (RF) ablation of common atrioventricular nodal reentrant tachycardia (AVNRT), guided by nonfluoroscopic mapping with use of the EnSite NavX cardiac mapping system (St. Jude Medical, Inc.; St. Paul, Minn) in a patient who long before had undergone Mustard repair for D-TGA. Case ReportIn 2013, a 49-year-old woman with a 3-year history of recurrent supraventricular tachycardia at 175 beats/min (responsive to intravenous adenosine) was referred for catheter ablation. At the age of 4 years, she had undergone a Mustard repair for D-TGA. No detailed report of her surgical anatomy was available. Therefore, cardiac magnetic resonance imaging was performed before ablation: it showed the right and left pulmonary veins diverted to the right (pulmonary venous) atrium and the superior and inferior venae cavae (SVC and IVC) diverted by an atrial baffle to the left (systemic venous) atrium. A 12-lead electrocardiogram showed both sinus rhythm with criteria for right ventricular (RV) hypertrophy with right-axis deviation (Fig. 1A) and supraventricular tachycardia that suggested common AVNRT (Fig. 1B). During an electrophysiologic study performed after informed consent was obtained, diagnostic and ablation catheters were placed with use of fluoroscopy and were displayed on the screen of the EnSite NavX system. Via the right femoral vein, we deployed a 6F hexapolar catheter in the SVC for stimulation and recording from the pulmonary venous atrium, a 6F quadripolar catheter for stimulation and recording Case Reports