Together, the association between thickened PV-LA junction walls and AF and the increased bipolar voltage suggests that such wall thickening increases PV electrical activities, leading to initiation and maintenance of AF and perhaps to ATP-provoked dormant PV conduction.

Despite reverse remodeling, the inflammation and collagen turnover biomarker levels are quite progressive during the 1st year after ablation and may explain the late AF recurrence.

A thickened PV-LA junction wall is a robust predictor of ATP-provoked dormant conduction; EGM-based information appears to be insufficient for ensuring adequate lesions during CF-guided EEPVI.

LA-EAT tends to overlie the major anatomical GP areas including most of the active GP response sites and CFAEs associated with AF. Ablation of GPs and CFAEs may explain the long-term efficacy of EAT-based ablation following extensive encircling pulmonary vein isolation (EEPVI) for AF.

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Key Wordsatrial fibrillation, cryoballoon ablation, pulmonary vein isolation, pulmonary vein distension. IntroductionCryothermal energy has emerged as an alternative ablation energy that does not issue in the clot formation and excessive tissue damage that occur with radiofrequency (RF) energy-based catheter ablation. [1] Although cryothermal energy is a milder and safer form of energy than RF energy, pulmonary vein isolation (PVI) performed with a second-generation cryoballoon has been highly successful in cases of paroxysmal atrial fibrillation (AF) and comparable to PVI performed by point by point-based RF ablation [2]-[6] or even contact force (CF)-based RF ablation.[7], [8] Despite the efficacy of cryoballoon ablation (CBA), however, some patients suffer recurrence of the AF, due mainly to PV reconnections or to non-PV triggers.[9], [10] Thus far, the mechanisms explaining durable and non-durable lesion formation around the PV ostium by means of second-generation CBA have not been fully investigated. Because establishing good balloon surface-totissue contact is essential for successful CBA of AF, we investigated, by means of 3-dimensional (3D) geometric imaging, how the inflated balloon surface contacts the 4 PVs. We then characterized lesions created around the PV ostia by CBA and those created by CF-based ablation to clarify the mechanism responsible for the efficacy of CBA. Material and Methods Study PatientsThe study involved 112 consecutive patients treated for AF (symptomatic paroxysmal AF [n=88] or persistent AF [n=24]) at Nihon University Itabashi Hospital between September 2014 and December 2015. The patient series comprised 72 men and 40 women with a mean±SD age of 63.8±7.7 years and median duration of AF of 18 months (interquartile range, 6-48 months). Patients were blindly (but not randomly) assigned to 1 of 2 ablation procedures: PVI performed by means of second-generation CBA (CBA group, n=56) and PVI performed by means of CF-based RF catheter ablation (CF group, n=56). Written informed consent was obtained from all patients. All antiarrhythmic drugs were withdrawn for at least 5 half-lives prior to the procedure. Transesophageal and transthoracic echocardiography were performed 1 day before the ablation procedure with an ACUSON Sequoia C256 echocardiography system (Siemens Medical Solutions USA, Inc., Malvern, PA). LA diameter (LAD) and maximum LA volume (by the prolate ellipsoid method) were determined, and the left ventricular ejection fraction (LVEF) was determined by means of M-mode echocardiography (Teichholz method). Multi-slice computed tomography was performed with a 320-detector row, dynamic volume scanner (Aquilion ONE; Toshiba Medical Systems, Tokyo, Japan) in all patients for 3D reconstruction of the left atrium (LA) and PVs before ablation. Electrophysiologic Study and AblationElectrophysiologic study was performed in all patients under conscious sedation achieved with dexmedetomidine and fentanyl.www.jafib.com Apr-May 2017| Volume 9| Issue 6Abstract Background: The mechanism ex...

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The strict catheter stability setting for automated lesion tagging together with a target FTI of >400 g*s, vs. the moderate catheter stability setting with a target FTI of >300 g*s, produces less frequent ATP-provoked PV conduction and yields a comparably high mid-term success rate.