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Aims: Cryoballoon ablation is safe and efficient for achieving pulmonary vein isolation (PVI) in atrial fibrillation. Structural oesophago-mediastinal lesions, which seem to be associated with an increased risk of the lethal complication of an atrio-oesophageal fistula, have been described. MADE-PVI (Mediastino-oesophageal Alterations Detected by Endosonography after PVI) aimed at evaluating safety of cryoballoon PVI in relation to two different freeze protocols. As time-to-isolation-(TTI)-guided protocol has been reported to be as effective as conventional 'two freeze protocol', we hypothesized a TTI-guided protocol causes less oesophago-mediastinal lesions., Methods and Results: Seventy consecutive patients were scheduled for cryoballoon (2nd generation) PVI employing either a conventional protocol (n = 35: 2 × 180 s per vein) or a TTI-guided approach (n = 35: TTI + 120 s per vein or 1 × 180 s in case TTI could not be measured). Oesophagogastroduodenoscopy and endoscopic ultrasound, assessing oesophago-mediastinal alterations (e.g. ulceration, oedema) were performed blinded prior and post-ablation. Post-interventional mediastinal oedematous alterations were detected in 70% with a mean diameter of 14 mm (±0.9 mm), while only 15% revealed large mediastinal oedema >20 mm. Oesophageal lesions due to PVI occurred in 5%. Freeze protocols had a distinct impact on oesophago-mediastinal alterations as mean diameter and frequency of large oedema were significantly increased in patients after conventional protocol PVI (17 mm vs. 11 mm; 26% vs. 6%). Furthermore, every oesophageal lesion was detected in patients with conventional protocol (9%). No major complication occurred in either group., Conclusion: The present prospective study demonstrates a significant impact of freeze protocol on oesophago-mediastinal alterations. A TTI-guided protocol reduces mediastino-oesophageal lesions and may reduce short- and long-term complications of cryoballoon PVI., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background: There is a lack of procedural and follow-up data on pulmonary vein isolation (PVI) with the second-generation pulmonary vein ablation catheter® (PVAC Gold) in patients with atrial fibrillation (AF). This study provides data on PVI procedures and 1-year follow-up results with PVAC Gold in patients with AF treated in clinical practice., Methods and Results: Three hundred and eighty four patients with documented symptomatic paroxysmal (n=198) or persistent (n=186) AF were included in a non-randomized prospectively designed database. Patients were enrolled consecutively at 2 high-volume centers. Procedural as well as 1year follow-up data were systematically analyzed. Average procedure times±standard deviations were 94±23min and 97±23min, respectively, in patients with paroxysmal and persistent AF. Average fluoroscopy times were 14.7±5.4min and 15.2±5.6min and total application times 18.1±5.0min and 18.8±5.2min, respectively, in the 2 patient cohorts. At 12months, 70.7% (70/99) and 61.9% (70/113) of patients with paroxysmal and persistent AF, respectively, were free from AF. Four early complications occurred. In the group with persistent AF, 1 posterior cerebral infarction occurred 2days after the procedure during initiation of anticoagulation. There was no phrenic nerve palsy or esophageal injury associated with the procedures. No thromboembolic events were recorded during follow-up., Conclusions: In patients with paroxysmal or persistent AF, second generation multi-electrode-phased radiofrequency ablation delivers favorable mid-term PVI success rates with few procedure-related or follow-up complications., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Increasing evidence supports a role of inflammation in the development of atrial fibrillation (AF). However, direct evidence of persistent inflammatory activity in the atria of AF patients is scarce. In this study, we used 18-Fluor-Deoxyglucose positron emission tomography computed tomography ( 18 F-FDG PET/CT) to determine atrial inflammation in patients with and without AF. Retrospectively, 18 F-FDG PET/CT scans were analyzed. 37 patients with a history of AF were compared to an age and sex matched control group with no history of AF. Standardized uptake values were obtained in the atrial walls, in the left ventricular wall, and in the right ventricular blood pool, respectively. Target to background ratios (TBR) were determined in the atrial and left ventricular walls and compared between the two groups. TBR values of the left atrial wall were slightly but not significantly higher in patients with AF (1.21 ± 0.27) compared to those without AF (1.14 ± 0.29; p = 0.85). Likewise, a weak but not significant difference was observed in signal intensities in the right atrial wall between patients in the AF (1.14 ± 0.45) and the control group (0.96 ± 0.2; p = 0.41). TBR values of the left ventricular myocardium did not differ between the groups; no significant correlation was found between the TBR in the left and right atrial wall and blood glucose levels. 18 F-FDG PET/CT performed under routine conditions did not detect a significant difference in inflammatory activity in the left or right atrium between patients with and without AF. Contrary to previous reports, these results therefore do not clearly support a role for ongoing atrial inflammation in patients with AF. Prospective clinical studies using myocardial glucose uptake suppression strategies may be helpful to clarify these issues.

Background: Ivabradine is an inhibitor of mixed Na + -K + -currents and routinely administered in chronic heart failure. Clinical studies reported divergent trends regarding proarrhythmic and antiarrhythmic effects in atrial fibrillation (AF)., Methods and Results: In 12 isolated rabbit hearts AF was induced in 7 of 12 hearts (13 episodes) under baseline conditions by a standardized protocol employing atrial burst pacing. Thereafter, a combination of acetylcholine and isoproterenol was employed to enhance AF occurrence. Monophasic action potential recordings showed a decrease of atrial action potential duration (aAPD,-37ms, p<0.05) and atrial effective refractory period (aERP;-39ms, p<0.05) after infusion of both acetycholine (1μM) and isoproterenol (1μM) as compared with baseline. This led to induction of AF in 11 of 12 hearts (124 episodes). Simultaneous infusion of ivabradine (3μM) led to a significant reduction of AF (6 of 11 hearts, 63 episodes). Ivabradine induced an increase of aAPD (+9ms) and aERP (+30ms, p<0.05) leading to a marked increase of atrial post-repolarization refractoriness (aPRR), defined as the difference of aERP and aAPD (+21ms, p<0.05). Results were compared to 10 rabbits treated with flecainide. Flecainide treatment also induced a significant increase of aPRR and resulted in induction of AF in 6 of 10 hearts (58 episodes) while 9 of 10 hearts were inducible during sole treatment with acetylcholine and isoproterenol (129 episodes)., Conclusion: In the present experimental study, administration of ivabradine reduced inducibility of AF and therefore may represent a supplemental therapeutic option in AF. Of note, its antiarrhythmic efficacy was comparable to the established agent flecainide., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Introduction: The antihistaminic antazoline (ANT) was reported to be highly effective and safe for rapid conversion of atrial fibrillation (AF). We therefore analyzed underlying mechanisms in an experimental whole-heart model., Methods and Results: Isolated and retrogradely perfused rabbit hearts underwent a standardized protocol employing atrial burst pacing-induced AF in five of 20 hearts under baseline conditions (seven episodes). Thereafter, a combination of acetylcholine and isoproterenol was employed to enhance AF occurrence. Two monophasic action potential recordings on the left- and two on the right atrial epicardium showed a decrease in atrial action potential duration (aAPD, -25 msec, P<.05) and atrial effective refractory period (aERP; -52 msec, P<.01) after infusion of acetylcholine (1 μmol/L) and isoproterenol (1 μmol/L). This led to induction of AF in 14 of 20 hearts (145 episodes). Simultaneous infusion of ANT (20 μmol/L) led to a complete suppression of AF in all inducible hearts. Treatment with ANT also led to a significant increase in aAPD (+41 msec, P<.01) and aERP (+74 msec, P<.05), leading to a marked increase in atrial postrepolarization refractoriness (aPRR, +33 msec, P<.01). Results were compared to 13 rabbits treated with flecainide. Flecainide induced a significant increase in aPRR and resulted in induction of AF in seven of 13 hearts (51 episodes) while 11 of 13 hearts were inducible with acetylcholine and isoproterenol (93 episodes)., Conclusion: Administration of ANT was highly effective in suppressing AF. The antiarrhythmic effect could be explained by a significant increase in postrepolarization refractoriness as a result of a more marked increase in aERP as compared with aAPD., (© 2016 John Wiley & Sons Ltd.)

Background: Assumption of different substrates is the basis for different ablation strategies in patients with paroxysmal and persistent atrial fibrillation (AF). We aimed to investigate pulmonary vein reconnection and influence on progression of initial paroxysmal (pAF) versus persistent atrial fibrillation (perAF)., Methods: Between January 2010 and November 2012, 149 patients (117 men, mean age 59 ± 11 years, range 27-80 years) underwent at least one redo antral pulmonary vein isolation (PVI) using NavX-guided irrigated-tip radiofrequency catheter ablation. We analyzed whether and where reconnection of pulmonary veins was detected, and whether there were differences between patients with pAF and perAF., Results: Of the 149 patients who underwent a redo antral PVI, 80 patients had pAF and 69 had perAF. One, two and three redo PVIs were performed in 149, 26 and 6 patients, respectively. Reconnection of at least one PV was detected in all patients at the second PVI, in 19 of 26 patients (73 %) at the third PVI and 5 of 6 patients (83 %) at the fourth PVI. 20 (29 %) patients with perAF prior to the first PVI had pAF at the second PVI, whereas 15 (19 %) patients with initial pAF had persistent AF at the time of the first redo procedure. From the second to the third PVI, four patients had developed perAF after previous pAF and two with per AF now had pAF. PV reconnection was observed independent of underlying AF type. At the second redo procedure, of those with reconnected veins 12 had pAF and 13 perAF. At the third redo procedure, four patients had pAF and four perAF., Conclusion: Most patients with recurrent AF after PVI showed at least one reconnected vein during redo procedures. Reconnection was identified irrespective of the underlying AF type. Progression from pAF to perAF and vice versa was observed irrespective of the initial AF type.

Background: Left atrial tachycardias (LAT) occur in about 5% of patients after irrigated-tip circumferential antral (CA) pulmonary vein isolation (PVI). They may cause debilitating symptoms in the patient and may be very difficult to treat., Objective: To assess the incidence of LAT after PVI with the multielectrode phased-radiofrequency pulmonary vein ablation catheter (PVAC) compared to circumferential antral PVI with an irrigated-tip catheter., Methods: We analyzed data from our ablation database. A total of 150 patients who underwent their first PVI with the PVAC system and 300 patients who underwent their first PVI with irrigated-tip circumferential antral (CA) radiofrequency ablation were matched by age and sex, as well as by type of atrial fibrillation., Results: Of 150 PVAC patients, only 1 patient (0.7%) developed LAT during mean follow-up of 21 ± 14 months. The mechanism was macroreentry and the patient underwent successful ablation at our institution. Eleven of 300 irrigated-tip CA PVI patients (3.7%) developed LAT during mean follow-up of 22 ± 14 months and subsequently underwent ablation (P = .05)., Conclusion: LAT occurs more frequently after irrigated-tip CA PVI compared to single-shot-device ablation with PVAC. Apart from being less technically demanding, lower incidence of LAT may influence choice of ablation technology., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Aims: The second-generation multi-electrode-phased radiofrequency pulmonary vein ablation catheter (PVAC GOLD(®)) was redesigned with the intent to improve its safety and efficacy., Methods and Results: Using a prospectively designed single-centre database, we retrospectively analysed 128 consecutive patients (102 paroxysmal and 43 female) who underwent their first pulmonary vein isolation with the PVAC GOLD(®). The analysis focused on procedural data as well as in-hospital complications. Baseline characteristics of the patient collective were as follows: mean age 57.9 years, mean CHA2DS2-VASC was 1.73 ± 1.30; structural heart disease was present in seven patients. The PVAC GOLD(®) exhibited procedure durations of 123.1 min ± 27.9, duration of energy delivery was 18.3 min ± 11.4, and fluoroscopy duration was 16.0 min ± 7.7. The redesigned catheter shows major complication [major bleeding, transitory ischaemic attack (TIA), and pericardial tamponade] rates of 2.3% (n = 3). The overall rate of adverse events was 5.4% (n = 7). Bleeding complications were observed in three patients (2.3%), in particular there were two cases (1.6%) of minor bleeding and one case (0.8%) of major bleeding. Two patients suffered pericardial effusion, but there was no need for pericardiocentesis. Besides one TIA, there was no other thrombo-embolic event. Furthermore, one case of post-procedural fever was observed. No deaths, stroke, or haemorrhagic shock occurred. Of the 510 pulmonary veins, 508 could be reached with the PVAC GOLD(®) device using a non-steerable long sheath., Conclusion: The PVAC GOLD(®) seems to have an acceptable safety profile. The handling is comparable with the previous generation PVAC(®)., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Background: The development of esophageal lesions following atrial fibrillation (AF) ablation has frequently been reported. Mediastinal tissue layers and the posterior wall of the left atrium are in close proximity to the site of ablation. Hence, mucosal lesions might solely represent the "tip of the iceberg." We therefore investigated patients undergoing multielectrode phased radiofrequency (RF) ablation (PVAC®, Medtronic Inc., Minneapolis, MN, USA) for symptomatic AF by radial endosonography (EUS) in conjunction with conventional endoscopy esophago-gastro-duodenoscopy (EGD) to visualize potential mediastinal injuries following pulmonary vein isolation (PVI)., Methods and Results: Eighteen patients (six women, mean age 52.8 ± 12.8 years, range 32-72 years) underwent PVI using multielectrode phased RF ablation and EGD and EUS following PVI within 48 hours. Postablation periesophageal lesions were detected by EUS in 10 out of 18 patients (56%). Four out of 10 lesions consisted of mild changes like small pericardial effusions, whereas six out of 10 patients had more severe lesions of the mediastinum, including one patient with changes of the esophageal mucosa. No atrio-esophageal fistula developed during follow-up (FU; mean FU 215 ± 105 days)., Conclusions: Mediastinal and esophageal structural changes occurred in a substantial number of patients. These findings highlight the necessity of close FU and the awareness of the potential development of an atrio-esophageal fistula also after multielectrode catheter ablation., (© 2015 Wiley Periodicals, Inc.)

Background: Silent cerebral lesions with the multielectrode-phased radiofrequency (RF) pulmonary vein ablation catheter (PVAC(®)) have recently been investigated. However, comparative data on safety in relation to irrigated RF ablation are missing., Methods and Results: One hundred and fifty consecutive patients (58 ± 12 years, 56 female) underwent first pulmonary vein isolation (PVI) for atrial fibrillation (61% paroxysmal) using PVAC(®) (PVAC). Procedure data as well as in-hospital complications were compared with 300 matched patients who underwent PVI using irrigated RF (iRF). Procedure duration (148 ± 63 vs. 208 ± 70 min; P < 0.001), RF duration (24 ± 10 vs. 49 ± 25 min; P < 0.001), and fluoroscopy time (21 ± 10 vs. 35 ± 13 min; P < 0.001) were significantly shorter using PVAC. Major complication rates [major bleeding, transitoric ischaemic attack (TIA), and pericardial tamponade] were not significantly different between groups (PVAC, n = 3; 2% vs. iRF n = 17; 6%). Overall complication rate, including minor events, was similar in both groups [n = 21 (14%) vs. n = 48 (16%)]. Most of these were bleeding complications due to vascular access [n = 8 (5.3%) vs. n = 22 (7.3%)], which required surgical intervention in five patients [n = 1 (0.7%) vs. n = 4 (1.3%)]. Pericardial effusion [n = 4 (2.7%) vs. n = 19 (6.3%); pericardial tamponade requiring drainage n = 0 vs. n = 6] occurred more frequently using iRF. Two patients in each group developed a TIA (1.3% vs. 0.6%). Of note, four of five thromboembolic events in the PVAC group (two TIAs and three transient ST elevations during ablation) occurred when all 10 electrodes were used for ablation., Conclusion: Pulmonary vein isolation using PVAC as a 'one-shot-system' has a comparable complication rate but a different risk profile. Pericardial effusion and tamponade occurred more frequently using iRF, whereas thromboembolic events were more prevalent using PVAC. Occurrence of clinically relevant thromboembolic events might be reduced by avoidance of electrode 1 and 10 interaction and uninterrupted anticoagulation, whereas contact force sensing for iRF might minimize pericardial effusion., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Aims: Phased radiofrequency (RF) ablation for atrial fibrillation is associated with an increased number of silent cerebral lesions on magnetic resonance imaging and cerebral microembolic signals (MESs) on transcranial Doppler ultrasound imaging compared with irrigated RF. The increased rate of embolic events may be due to a specific electrical interference of ablation electrodes attributed to the catheter design. The purpose of this study was to elucidate the effect of deactivating the culprit electrodes on cerebral MESs., Methods and Results: Twenty-nine consecutive patients (60 ± 11 years, 10 female) underwent their first pulmonary vein isolation using phased RF energy. Electrode pairs 1 or 5 were deactivated to avoid electrical interference between electrodes 1 and 10 ('modified'). Detection of MESs by transcranial Doppler ultrasound was performed throughout the procedure to assess cerebral microembolism. Results were compared with the numbers of MESs in 31 patients ablated using all available electrodes ('conventional') and to 30 patients undergoing irrigated RF ablation of a previous randomized study. Ablation with 'modified' phased RF was associated with a marked decrease in MESs when compared with 'conventional' phased RF (566 ± 332 vs. 1530 ± 980; P < 0.001). This difference was mainly triggered by the reduction of MES during delivery of phased RF energy, resulting in MES numbers comparable to irrigated RF ablation (646 ± 449; P = 0.7). Total procedure duration as well as time of RF delivery was comparable between phased RF groups. Both times, however, were significantly shorter compared with the irrigated RF group (123 ± 28 vs. 195 ± 38; 15 ± 4 vs. 30 ± 9; P < 0.001, respectively)., Conclusion: Pulmonary vein isolation with 'modified' phased RF is associated with a decreased number of cerebral microembolism especially during the delivery of ablation impulses, supporting the significance of electrical interference between ablation electrodes 1 and 10. Deactivation of electrode pairs 1 or 5 might increase the safety of this approach without an increase in procedure duration or RF delivery time.

Background and Purpose: A significant number of patients with cryptogenic stroke suffer from intermittent atrial fibrillation (iAF) which was not detected during the standard diagnostic procedures. We investigated whether implantation of an insertable cardiac monitor (ICM) is feasible in patients with cryptogenic stroke, and compared the iAF detection rate of the ICM with 7-day Holter monitoring., Methods: Sixty patients (median age 63; interquartile range, 48.5-72 years) with acute cryptogenic stroke were included. ICM was implanted 13 days (interquartile range; 10-65 days) after the qualifying event. Seven-day Holter was performed after the ICM was implanted., Results: The iAF was detected by the ICM in 10 patients (17%; 95% CI, 7% to 26%). Only 1 patient (1.7%; 95% CI, 0% to 5%) had iAF during 7-day Holter monitoring as well (P=0.0077). Episodes of iAF lasting 2 minutes or more were detected 64 (range, 1-556) days after implantation. There were no recurrent strokes during the observation period. The implantation procedure was well tolerated with no adverse events; the daily data transmission protocol was easy to handle by the patients., Conclusions: ICM implantation for the detection of iAF during outpatient follow-up is feasible in patients with cryptogenic stroke. ICMs offer a much higher diagnostic yield than 7-day Holter monitoring.

Background: The risk of developing a stroke or systemic embolus due to a left atrial (LA) thrombus in patients with atrial fibrillation (AF) and/or atrial flutter (AFL) is estimated by the CHADS(2) score and more recently the CHA(2)DS(2)-VASc score. We aimed to further characterize AF/AFL patients who were found to have a LA thrombus on a transesophageal echocardiogram (TEE)., Methods and Results: Of 3,165 TEE between 2005 and 2011 for a broad spectrum of indications, we detected 65 AF patients with LA thrombus (2 %). There were 40 men and 25 women, mean age was 65 ± 13 years (range 36-88 years). Mean CHADS(2) score was 1.8 ± 1.1 and mean CHA(2)DS(2)-VASc score was 3.0 ± 1.6. 11 patients (17 %) had a CHADS(2) score of 0, 12 patients (18 %) of 1, 28 patients (43 %) of 2 and 12 patients (18 %) of 3. Hypertension was the most frequent risk factor (72 %), followed by congestive heart failure (32 %), diabetes (23 %) and age ≥75 years (23 %). Mean difference between CHADS(2) and CHA(2)DS(2)-VASc was 1.25 ± 0.91. Of the 11 patients (17 %) with a LA thrombus despite a CHADS(2) score of 0, five had a CHA(2)DS(2)-VASc score of 0, four a CHA(2)DS(2)-VASc score of 1 and two a CHA(2)DS(2)-VASc score of 2., Conclusion: In an unselected TEE population with newly detected LA thrombus about one-third of patients fell into the low-risk group when classified based on the CHADS(2) score, while a much lower population fell in the same low-risk group when classified according to the CHA(2)DS(2)-VASc score. However, this does not prove clinical superiority of the CHA(2)DS(2)-VASc score over the established CHADS(2) score. Whether our observation has clinical implications (e.g. TEE prior to LA ablation irrespective of CHADS(2) score), or argues for use of the CHA(2)DS(2)-VASc score needs to be evaluated in prospective studies.

Aims: Ranolazine (RAN) was reported to be effective and safe in converting atrial fibrillation (AF) to sinus rhythm by administration of a single dose ('pill in the pocket') to patients with structural heart disease. This study examines the underlying mechanisms for the antiarrhythmic benefit of RAN application in chronic heart failure (CHF)., Methods and Results: In 10 female rabbits, CHF was induced by rapid ventricular pacing, leading to a significant decrease in ejection fraction in the presence of a dilated left ventricle and atrial enlargement. Twelve rabbits were sham-operated and served as controls. Isolated hearts were perfused using the Langendorff method. Burst pacing was used to induce AF. Monophasic action potential recordings showed an increase of atrial action potential duration (aAPD) and effective refractory period (aERP) in CHF hearts compared with sham hearts. Infusion of acetylcholine (1 µM) and isoproterenol (1 µM) led to AF in all failing hearts and in 11 sham hearts. Simultaneous infusion of RAN (10 µM) remarkably reduced inducibility of AF in 50% of sham and 50% of failing hearts. RAN had no effect on aAPD but significantly increased aERP, leading to a marked increase in atrial post-repolarization refractoriness. Moreover, RAN application moderately increased interatrial conduction time., Conclusion: RAN has been shown to be effective in reducing the inducibility of AF in an experimental model of AF. The antiarrhythmic effect is mainly due to development of atrial post-repolarization refractoriness and a moderate increase in conduction time. The described electrophysiological mechanisms remain preserved in the setting of CHF.

Aims: Pulmonary veins (PV) play a pivotal role in atrial fibrillation (AF). Anatomical variants of PV have been described and related to a higher arrhythmogenic potential. The aim of this study was to compare the prevalence of PV variants and diameters of PV ostia in AF patients and controls., Methods and Results: Variants of PV were defined as right or left common ostia (RCO, LCO), a right middle or right top PV . A long common trunk (LCT) was defined as an LCO with a distance to the first branching ≥ 10 mm. Multislice contrast-enhanced thoracic computed tomography was performed prior to AF ablation in 166 consecutive patients, 47.6% with paroxysmal, 52.4% with persistent AF, as well as in a sex- and age-matched control group without AF, for non-cardiological indications. Images were evaluated by two independent observers. The mean age was 59 ± 10 years, 108 were men (65.1%). A higher prevalence of LCO was found in the AF group: 33.7 vs. 19.9% (P= 0.004), odds ratio (OR) 2.1; 15.4% in patients vs. 10.2% in controls had an LCT (P= 0.14). No differences in other PV variants were found. The ostial diameters were greater in AF-patients (P< 0.001)., Conclusions: To the best of our knowledge, the present study shows for the first time a higher prevalence of an LCO in patients with AF as compared with controls, with an OR of 2.1. This suggests a pre-disposing role of LCO in the development of AF.

Background: Pulmonary vein (PV) electrical isolation is a therapeutic option in atrial fibrillation (AF). New technologies may reduce the complexity of the procedure., Objective: The aim of the present study was to compare immediate results and short-term efficacy of a new circular ablation catheter (PVAC) with a conventional point-by-point ablation., Methods: The prospective study enrolled 80 consecutive patients with paroxysmal AF or persistent AF, refractory to antiarrhythmic drugs, who were randomized to radiofrequency ablation using duty-cycled bipolar and unipolar radiofrequency by a decapolar circular catheter (PVAC group) or to point-by-point ablation supported by a 3-dimensional mapping system (3D group)., Results: Forty patients per group were included. Mean age was 58 ± 10 years, 64% were male; 55% had paroxysmal AF, 45% had persistent AF. There were no significant differences between groups. Complete electrical isolation was reached in all but 1 PV, which was not isolated in the PVAC group because of phrenic nerve capture. Procedure and fluoroscopy times were lower in the PVAC group: 171 ± 40 minutes vs. 224 ± 27 minutes, P < .001; 26 ± 8 minutes vs. 35 ± 9 minutes, P < .001; respectively. There were no major complications. During a mean follow-up of 254 ± 99 days, 72% in the PVAC group and 68% in the 3D group were free of AF recurrences irrespective of the initial AF type (P = NS)., Conclusion: PVAC represents a safe alternative for PV isolation. It reduces both procedure and fluoroscopy time. The short- and middle-term efficacy is comparable to a conventional point-by-point antral ablation technique., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

AimsIn atrial fibrillation, increased function of the Na+/Ca2+-exchanger (NCX) is one among several electrical remodeling mechanisms.Methods/resultsUsing the patch-clamp- and Ca2+ imaging-methods, we investigated atrial myocytes from NCX-homozygous-overexpressor (OE)- and heterozygous-knockout (KO)-mice and their corresponding wildtypes (WTOE; WTKO). NCX mediated Ca2+ extrusion capacity was reduced in KO and increased in OE. There was no evidence for structural or molecular remodeling. During a proarrhythmic pacing-protocol, the number of low amplitude delayed afterdepolarizations (DADs) was unaltered in OE vs. WTOE and KO vs. WTKO. However, DADs triggered full spontaneous action potentials (sAP) significantly more often in OE vs. WTOE (ratio sAP/DAD: OE:0.18±0.05; WTOE:0.02±0.02; p

Background: Silent cerebral lesions with the multielectrode-phased radiofrequency (RF) pulmonary vein ablation catheter (PVAC(®)) have recently been investigated. However, comparative data on safety in relation to irrigated RF ablation are missing.Methods and Results: One hundred and fifty consecutive patients (58 ± 12 years, 56 female) underwent first pulmonary vein isolation (PVI) for atrial fibrillation (61% paroxysmal) using PVAC(®) (PVAC). Procedure data as well as in-hospital complications were compared with 300 matched patients who underwent PVI using irrigated RF (iRF). Procedure duration (148 ± 63 vs. 208 ± 70 min; P < 0.001), RF duration (24 ± 10 vs. 49 ± 25 min; P < 0.001), and fluoroscopy time (21 ± 10 vs. 35 ± 13 min; P < 0.001) were significantly shorter using PVAC. Major complication rates [major bleeding, transitoric ischaemic attack (TIA), and pericardial tamponade] were not significantly different between groups (PVAC, n = 3; 2% vs. iRF n = 17; 6%). Overall complication rate, including minor events, was similar in both groups [n = 21 (14%) vs. n = 48 (16%)]. Most of these were bleeding complications due to vascular access [n = 8 (5.3%) vs. n = 22 (7.3%)], which required surgical intervention in five patients [n = 1 (0.7%) vs. n = 4 (1.3%)]. Pericardial effusion [n = 4 (2.7%) vs. n = 19 (6.3%); pericardial tamponade requiring drainage n = 0 vs. n = 6] occurred more frequently using iRF. Two patients in each group developed a TIA (1.3% vs. 0.6%). Of note, four of five thromboembolic events in the PVAC group (two TIAs and three transient ST elevations during ablation) occurred when all 10 electrodes were used for ablation.Conclusion: Pulmonary vein isolation using PVAC as a 'one-shot-system' has a comparable complication rate but a different risk profile. Pericardial effusion and tamponade occurred more frequently using iRF, whereas thromboembolic events were more prevalent using PVAC. Occurrence of clinically relevant thromboembolic events might be reduced by avoidance of electrode 1 and 10 interaction and uninterrupted anticoagulation, whereas contact force sensing for iRF might minimize pericardial effusion. [ABSTRACT FROM AUTHOR]

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Aims In atrial fibrillation, increased function of the Na + /Ca 2 + -exchanger (NCX) is one among several electrical remodeling mechanisms. Methods/results Using the patch-clamp- and Ca 2 + imaging-methods, we investigated atrial myocytes from NCX-homozygous-overexpressor (OE)- and heterozygous-knockout (KO)-mice and their corresponding wildtypes (WT OE ; WT KO ). NCX mediated Ca 2 + extrusion capacity was reduced in KO and increased in OE. There was no evidence for structural or molecular remodeling. During a proarrhythmic pacing-protocol, the number of low amplitude delayed afterdepolarizations (DADs) was unaltered in OE vs. WT OE and KO vs. WT KO . However, DADs triggered full spontaneous action potentials (sAP) significantly more often in OE vs. WT OE (ratio sAP/DAD: OE:0.18 ± 0.05; WT OE :0.02 ± 0.02; p < 0.001). Using the same protocol, a DAD triggered an sAP by tendency less often in KO vs. WT KO ( p = 0.06) and significantly less often under a more aggressive proarrhythmic protocol (ratio sAP/DAD: KO:0.01 ± 0.003; WT KO: 0.12 ± 0.05; p = 0.007). The DAD amplitude was increased in OE vs. WT OE and decreased in KO vs. WT KO . There were no differences in SR-Ca 2 + -load, the number of spontaneous Ca 2 + -release-events or IKACh/IK1. Conclusions Atrial myocytes with increased NCX expression exhibited increased vulnerability towards sAPs while atriomyocytes with reduced NCX expression were protected. The underlying mechanism consists of a modification of the DAD-amplitude by the level of NCX-activity. Thus, although the number of spontaneous Ca 2 + -releases and therefore DADs is unaltered, the higher DAD-amplitude in OE made a transgression of the voltage-threshold of an sAP more likely. These findings indicate that the level of NCX activity could influence triggered activity in atrial myocytes independent of possible remodeling processes. [ABSTRACT FROM AUTHOR]