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Purpose: 68  Ga-fibroblast-activation protein inhibitor (FAPI) positron emission tomography (PET) is a novel technique targeting FAP-alpha. This protein is expressed by activated fibroblasts which are the main contributors to tissue remodeling. The aim of this proof-of-concept study was to assess 68  Ga-FAPI uptake in the pulmonary vein (PV) region of the left atrium after pulmonary vein isolation (PVI) with cryoballoon ablation (CBA) and radiofrequency (RFA) as a surrogate for thermal damage., Methods: Twelve PVI patients (5 RFA, 7 CBA) underwent 68  Ga-FAPI-PET 20.5 ± 12.8 days after PVI. Five patients without atrial fibrillation or previous ablation served as controls. Standardized uptake values of localized tracer uptake were calculated., Results: Focal FAPI uptake around the PVs was observed in 10/12 (83.3%) PVI patients, no uptake was observed in 2 PVI patients and all controls. Patients after PVI had higher FAPI uptake in PVs compared to controls (SUV max : 4.3 ± 2.2 vs. 1.6 ± 0.2, p < 0.01; SUV peak : 2.9 ± 1.4 vs. 1.3 ± 0.2, p < 0.01). All CBA patients had an intense uptake, while in the RFA, group 2 (40%), 1 (20%), and 2 (40%) patients had an intense, moderate, and no uptake, respectively. We observed higher uptake values (SUV peak ) in CBA compared to RFA patients (4.4 ± 1.5 vs. 2.5 ± 0.8, p = 0.02)., Conclusion: We demonstrate in-vivo visualization of 68  Ga-FAPI uptake as a surrogate for fibroblast activation after PVI. CBA seems to cause more pronounced fibroblast activation following tissue injury than RFA. Future studies are warranted to assess if this modality can contribute to a better understanding of the mechanisms of AF recurrence after PVI by lesion creation and gap assessment., (© 2021. The Author(s).)

Pulmonary vein isolation (PVI) using cryoenergy is safe and efficient for treatment of atrial fibrillation (AF). Pre-existing upper gastrointestinal (GI) pathologies have been shown to increase the risk for AF. Therefore, this study aimed at assessing incidental pathologies of the upper GI tract in patients scheduled for PVI and to analyse the impact of patients' characteristics on PVI safety outcome. In 71 AF patients, who participated in the MADE-PVI trial, oesophagogastroduodenoscopy and endosonography were prospectively performed directly before and the day after PVI to assess pre-existing upper GI pathologies and post-interventional occurrence of PVI-associated lesions. Subgroup analysis of the MADE-PVI trial identified clinically relevant incidental findings in 53 patients (74.6%) with age > 50 years being a significant risk factor. Pre-existing reflux oesophagitis increased risk for PVI-associated mediastinal oedema, while patients already treated with proton pump inhibitors (PPI) had significantly fewer mediastinal oedema. Our results suggest that AF patients with pre-existing reflux oesophagitis are at higher risk for PVI-associated mediastinal lesions, which is decreased in patients with constant PPI-treatment prior to PVI. Since PVI-associated mediastinal lesions are regarded as surrogate parameter for an increased risk of the fatal complication of an oesophago-atrial fistula, our findings hint at a beneficial effect of pre-interventional prophylactic PPI-treatment to reduce risk for PVI-associated complications.German Clinical Trials Register (DRKS00016006; date of registration: 17/12/2018).

Introduction: Left atrial flutter predominantly occurs after surgical or ablation procedures but this entity has also been recently reported in individuals without previous interventions. The use of high-density electroanatomical mapping-systems (HDM) has improved the understanding of underlying mechanisms beyond entrainment maneuvers and substrate analyses. We aimed to evaluate the mechanism of left atrial (LA) flutters in preablated vs ablation-naïve individuals and sought to assess the efficacy of empiric ablations sets in these groups., Methods and Results: We included 55 patients admitted for ablation of LA flutter between July 2017 and August 2019. On the basis of HDM analyses the arrhythmia mechanism was determined with consecutive ablation targeting the suspected critical isthmus. Mean age was 69.8 ± 10.7 years, with 26 of 55 (47.3%) male patients. Thirty-nine (71%) patients had previously undergone LA ablation. Arrhythmia mechanisms differed between preablated and ablation-naïve patients as anatomical structure-related LA flutters (perimitral, roof-dependent, within-pulmonary veins) were more frequent in the preablated cohort compared to ablation-naïve individuals (74.4% vs 43.8%; P = .03). In ablation-naïve patients, most flutters (9 of 16, 56.3%) were related to low-voltage areas at the anterior/posterior wall. Acute termination rates were high (>90%) in both groups. Empirical mitral isthmus or roof lines showed a potential higher success rate in preablated patients., Conclusion: We identified different mechanisms of LA flutters in preablated vs ablation-naïve patients. In ablation-naïve patients, most tachycardias involved low-voltage areas rather than anatomical structures. Using HDM, acute success rates were high. Hypothetical linear ablations were less successful in ablation-naïve individuals, further highlighting the need to identify the specific individual tachycardia mechanism in these patients., (© 2020 Wiley Periodicals LLC.)

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: 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.

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.)

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.