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Abstract Background Currently, two types of cryoballoon (CB) systems are available for catheter ablation of atrial fibrillation (AF). Since the POLARx (Boston Scientific) is softer during freezing than the Arctic Front Advance Pro (AFA‐Pro; Medtronic), it tends to go more deeply into the pulmonary vein (PV), risking PV stenosis. Methods Ninety‐one patients underwent initial CB ablation for paroxysmal AF (AFA‐Pro 56; POLARx 35). Twenty‐six from each group were extracted using propensity score matching. The PV cross‐sectional area (PVA) was measured by tracing the area within the PV plane at 5‐mm intervals from the PV ostium in a distal direction for 20 mm or to the bifurcation in each PV. The PVA was compared before and 3 months after ablation. Results Time to balloon temperatures of −30 and − 40°C was significantly shorter and the nadir temperature was significantly lower with POLARx than with AFA‐Pro. In the left inferior (LI) PV and right superior (RS) PV, the freezing balloon position was significantly deeper in POLARx than in AFA‐pro. The freezing position in RSPV with mild to moderate narrowing was deeper than those without (10.2 ± 3.3 mm vs. 8.2 ± 1.8 mm, p = .01). In RSPV, the reduction of PVA tended to be greater with the POLARx than with the AFA‐Pro (26.1% ± 14.1% vs. 19.9% ± 10.3%, p = .07). Conclusion There was no significant difference in the incidence of PV stenosis between POLARx and AFA‐Pro. However, if POLARx goes deep into the PVs, we will still have to be careful.

Abstract Background Atrioventricular nodal reentrant tachycardia (AVNRT) sometimes recurs even after anatomical slow pathway (SP) ablation targeting the rightward inferior extension (RIE). This multicenter study aimed to determine the reasons for AVNRT recurrence. Methods and Results Forty‐six patients were treated successfully for recurrent AVNRT. Initial treatment was for 38 slow‐fast AVNRTs, 3 fast‐slow AVNRTs, 2 slow‐slow AVNRTs, 2 slow‐fast and fast‐slow AVNRTs, and 1 noninducible AVNRT. All initial treatments were of RF application to the RIE; SP elimination was achieved in 11, dual AVN physiology was seen in 29, and AVNRT remained inducible in 5. The recurrent AVNRTs included 34 slow‐fast AVNRTs, 6 fast‐slow AVNRTs, 3 slow‐slow AVNRTs, 2 slow‐fast and fast‐slow AVNRTs, and 1 slow‐fast and slow‐slow AVNRTs. Successful ablation site was within the RIE in 39 and left inferior extension in 7. In 30 of 39, the successful RIE site was in the same area or higher than that of the initial procedure. Conclusion For a high majority (around 85%) of patients in whom AVNRT recurs after initial ablation success, the site of a second successful procedure will be within the RIE even though the RIE was originally targeted. Furthermore, a high majority (around 86%) of sites of successful ablation will be higher than those originally targeted.

Abstract Background Hyperuricemia (HU) has been reported to be associated with a high incidence of atrial fibrillation (AF). However, the relationship between HUA and recurrent AF after catheter ablation (CA) is unclear. Methods Four hundred consecutive AF patients (paroxysmal/persistent AF [PAF/PsAF]: 200/200) who underwent the initial CA were retrospectively enrolled. HU was defined as serum uric acid (SUA) level >7.0 mg/dL. We measured SUA levels 1 day before (pre‐CA) and 1 month after CA (post‐CA). A second‐generation 28 mm cryoballoon was used for pulmonary vein isolation (PVI) for PAF, while PVI plus linear ablation (roof and mitral isthmus lines) by radiofrequency catheter was conducted for PsAF. Results During 57 ± 24 months of follow‐up, AF recurred in 16% and 42% in PAF and PsAF patients (p

We present the case of a patient who developed regular, narrow QRS tachycardia after ablation for long-standing persistent atrial fibrillation. During the electrophysiological study, this tachycardia was diagnosed as macroreentrant atrial tachycardia circulating around the mitral annulus. Catheter ablation was performed to treat the tachycardia by targeting the linear region between the annulus and the left inferior pulmonary vein. Although linear radiofrequency application along the mitral isthmus (MI) line resulted in the termination of this tachycardia, a unidirectional conduction block was observed through the MI. Bidirectional conduction block was subsequently achieved by delivering supplemental radiofrequency energies at the gap on the MI.

The case of a patient with narrow QRS tachycardia is herein presented. During an electrophysiological study, this tachycardia was diagnosed as a focal atrial tachycardia with a high sensitivity to adenosine-5′-triphosphate (2 mg), and originating from near the His-bundle region. We could not ablate the earliest activation site in the right atrium because of the simultaneous recording of the His potential. The radiofrequency applications in the right atrium around the earliest activation site failed to terminate the tachycardia. Subsequent attempt of radiofrequency application in the non-coronary aortic cusp, where the earliest atrial activation without His potential was obtained, successfully eliminated the tachycardia without any atrioventricular nodal injury.