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Background and Objectives: Long-term oral anticoagulation (OAC) following successful catheter ablation of atrial fibrillation (AF) remains controversial. Prospective data are missing. The ODIn-AF study aimed to evaluate the effect of OAC on the incidence of silent cerebral embolic events and clinically relevant cardioembolic events in patients at intermediate to high risk for embolic events, free from AF after pulmonary vein isolation (PVI)., Methods: This prospective, randomized, multicenter, open-label, blinded endpoint interventional trial enrolled patients who were scheduled for PVI to treat paroxysmal or persistent AF. Six months after PVI, AF-free patients were randomized to receive either continued OAC with dabigatran or no OAC. The primary endpoint was the incidence of new silent micro- and macro-embolic lesions detected on brain MRI at 12 months of follow-up compared to baseline. Safety analysis included bleedings, clinically evident cardioembolic, and serious adverse events (SAE)., Results: Between 2015 and 2021, 200 patients were randomized into 2 study arms (on OAC: n = 99, off OAC: n = 101). There was no significant difference in the occurrence of new cerebral microlesions between the on OAC and off OAC arm [2 (2%) versus 0 (0%); P = 0.1517] after 12 months. MRI showed no new macro-embolic lesion, no clinical apparent strokes were present in both groups. SAE were more frequent in the OAC arm [on OAC n = 34 (31.8%), off OAC n = 18 (19.4%); P = 0.0460]; bleedings did not differ., Conclusion: Discontinuation of OAC after successful PVI was not found to be associated with an elevated risk of cerebral embolic events compared with continued OAC after a follow-up of 12 months., (© 2023. The Author(s).)

Aims: Myocardial fibrosis is a hallmark of atrial fibrillation (AF) and its characterization could be used to guide ablation procedures. Late gadolinium enhanced-magnetic resonance imaging (LGE-MRI) detects areas of atrial fibrosis. However, its accuracy remains controversial. We aimed to analyse the accuracy of LGE-MRI to identify left atrial (LA) arrhythmogenic substrate by analysing voltage and conduction velocity at the areas of LGE., Methods and Results: Late gadolinium enhanced-magnetic resonance imaging was performed before ablation in 16 patients. Atrial wall intensity was normalized to blood pool and classified as healthy, interstitial fibrosis, and dense scar tissue depending of the resulting image intensity ratio. Bipolar voltage and local conduction velocity were measured in LA with high-density electroanatomic maps recorded in sinus rhythm and subsequently projected into the LGE-MRI. A semi-automatic, point-by-point correlation was made between LGE-MRI and electroanatomical mapping. Mean bipolar voltage and local velocity progressively decreased from healthy to interstitial fibrosis to scar. There was a significant negative correlation between LGE with voltage (r = -0.39, P < 0.001) and conduction velocity (r = -0.25, P < 0.001). In patients showing dilated atria (LA diameter ≥45 mm) the conduction velocity predictive capacity of LGE-MRI was weaker (r = -0.40 ± 0.09 vs. -0.20 ± 0.13, P = 0.02)., Conclusions: Areas with higher LGE show lower voltage and slower conduction in sinus rhythm. The enhancement intensity correlates with bipolar voltage and conduction velocity in a point-by-point analysis. The performance of LGE-MRI in assessing local velocity might be reduced in patients with dilated atria (LA diameter ≥45)., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

Background: The Micra transcatheter pacing system (Micra TPS) is often implanted in patients with atrial fibrillation and thus with increased thromboembolic risk. It is unknown whether the use of anticoagulants, associated with the use of a large venous introducer, implies an increased risk of bleeding in this group of patients., Objective: The purpose of this study was to assess the incidence of bleeding and thromboembolic complications after Micra TPS implantation with and without therapeutic anticoagulation., Methods: This single-center observational study included 107 consecutive patients receiving the Micra TPS from 2014 to 2018. At procedure completion, a figure-of-eight suture was placed at the femoral puncture site after sheath withdrawal and was maintained for 24 hours. In patients receiving enoxaparin or new oral anticoagulants, treatment was discontinued 12 or 24 hours before the procedure, respectively, and was reinitiated 4-6 hours postprocedure. In those receiving vitamin K antagonists (VKAs), dosing was not discontinued and the procedure was performed if the international normalized ratio was less than 3., Results: Sixty-four patients (60%) did not receive anticoagulants. Of the 43 (40%) who did, 29 (67%) received VKAs, 8 (19%) received new oral anticoagulants, and 6 (14%) received enoxaparin. Two patients presented hemorrhagic or thromboembolic complications during short-term follow-up: 1 woman receiving VKAs presented hemorrhagic pericardial effusion without tamponade and 1 woman not receiving anticoagulants presented thrombosis of the ipsilateral saphenous vein., Conclusion: Bleeding and thromboembolic complications after receiving Micra TPSs are infrequent. The use of anticoagulant therapy, regardless of the type, does not increase the complications associated with the procedure., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: There is limited knowledge about the impact of anatomic gaps as assessed by delayed gadolinium enhancement cardiac magnetic resonance on atrial fibrillation (AF) recurrence after first pulmonary vein (PV) isolation., Methods: Consecutive patients underwent delayed gadolinium enhancement cardiac magnetic resonance 3 months after radiofrequency circumferential PV isolation. Delayed gadolinium enhancement cardiac magnetic resonance images were assessed from 360 PV resulting in 2880 segments in the 2×8-segment model from 94 patients (52±11 years, 62% paroxysmal AF). Left atria were segmented using dedicated software. Anatomic gap was defined as discontinuation of the ablation line by ≥3 mm. Relative gap length was calculated as absolute gap length divided by the total length of the ablation line. AF recurrence was assessed after a mean follow-up duration of 15±10 months Results: Mean number of anatomic gaps was 5.4 per patient. Recurrence within the first year of ablation was observed in 21 patients with paroxysmal AF (36%) and 19 patients with persistent AF (53%). In the univariate analysis, CHA 2 DS 2 -VASc score, AF type, and relative gap length were predictive of recurrence. In the multivariate analysis, only relative gap length was significantly associated with recurrence (hazard ratio, 1.16 [1.02-1.31] per each 10% of gap)., Conclusions: The total relative gap length but not the number of anatomic gaps in the PV ablation line as assessed by delayed gadolinium enhancement cardiac magnetic resonance was associated with AF recurrence 1 year after first PV isolation. An increase of 10% relative gap length increased the likelihood of AF recurrence by 16%.

To determine the pre-procedural value of different fibrotic biomarkers and comprehensive cardiac magnetic resonance (CMR) for the prediction of poor response to ablation therapy in patients with atrial fibrillation (AF). Left atrial (LA) late gadolinium enhancement (LGE) and native LA T1 relaxation times were assessed using CMR. Plasma levels of relaxin, myeloperoxidase and serum levels of matrix metalloproteinase (MMP)-mediated cardiac specific titin fragmentation and MMP-mediated type IV collagen degradation were obtained. Poor outcome was defined by the recurrence of AF during 1-year follow-up. 61 patients were included in final analysis. Twenty (32.8%) patients had recurrence of AF. Patients with a recurrence of AF had a higher percentage of LA LGE (26.7 ± 12.5% vs. 17.0 ± 7.7%; P < 0.001), higher LA T1 relaxation times (856.7 ± 112.2 ms vs. 746.8 ± 91.0 ms; P < 0.001) and higher plasma levels of relaxin (0.69 ± 1.34 pg/ml vs. 0.37 ± 0.88 pg/ml; P = 0.035). In the multivariate Cox regression analysis, poor ablation outcome was best predicted by advanced LGE stage (hazard ratio (HR):5.487; P = 0.001) and T1 relaxation times (HR:1.007; P = 0.001). Pre-procedural CMR is a valuable tool for prediction of poor response to catheter ablation therapy in patients with AF. It offers various imaging techniques for outcome prediction and might be valuable for a better patient selection prior to ablation therapy.

Background: Pulmonary vein isolation (PVI) has become a widely accepted therapy in patients suffering from symptomatic atrial fibrillation (AF)., Hypothesis: AF-free survival differs in patients with left common pulmonary vein (LCPV) after PVI with second-generation cryoballoon., Methods: We included patients scheduled for first PVI for paroxysmal or persistent AF. Symptomatic and/or documented arrhythmia episodes (>30 seconds) were defined as AF recurrence, excluding a 3-month blanking period., Results: We observed a LCPV in 37 of 270 consecutive patients (13.7%). Analyses were performed in a 1:1 propensity score matched cohort of 68 patients. During a median follow-up of 77.0 weeks, 37 patients (54.4%) had recurrent AF. The prevalence of LCPV was numerically higher in patients with AF recurrence (62.2% vs 35.5%, P  =  0.051) and Kaplan-Meier analysis showed lower AF-free survival in patients with existence of a LCPV (P  =  0.028). At 1-year follow-up, 70.6% of patients without versus 55.1% of patients with LCPV were free of AF. Multivariate Cox regression analysis revealed presence of a LCPV (hazard ratio [HR]: 2.996), chronic heart failure (HR: 3.423), and mitral regurgitation > I° (HR: 2.571) as predictors of AF recurrence., Conclusion: Patients with LCPV had significantly reduced AF-free survival after ablation with the second-generation cryoballoon, despite similar acutely successful PVIs., (© 2017 Wiley Periodicals, Inc.)

Background: Relaxin-2 (RLX) is a peptide hormone that exerts beneficial anti-fibrotic and anti-inflammatory effects in diverse models of cardiovascular disease. The goal of this study was to determine the effects of RLX treatment on the susceptibility to atrial fibrillation (AF) after myocardial infarction (MI)., Methods: Mice with cryoinfarction of the left anterior ventricular wall were treated for two weeks with either RLX (75 μg/kg/d) or vehicle (sodium acetate) delivered via subcutaneously implanted osmotic minipumps., Results: RLX treatment significantly attenuated the increase in AF-inducibility following cryoinfarction and reduced the mean duration of AF episodes. Furthermore, epicardial mapping of both atria revealed an increase in conduction velocity. In addition to an attenuation of atrial hypertrophy, chronic application of RLX reduced atrial fibrosis, which was linked to a significant reduction in atrial mRNA expression of connective tissue growth factor. Transcript levels of the pro-inflammatory cytokines interleukin-6 and interleukin-1β were reduced in RLX treated mice, but macrophage infiltration into atrial myocardium was similar in the vehicle and RLX treated groups., Conclusion: Treatment with RLX in mice after MI reduces susceptibility to AF due to anti-inflammatory and anti-fibrotic properties. Because to these favorable actions, RLX may become a new therapeutic option in the treatment of AF, even when complicating MI., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Visually guided laserballoon (LB) ablation has recently been introduced for pulmonary vein (PV) isolation (PVI). We analyzed efficacy and safety results of the newly introduced LB ablation technique in patients with persistent and longstanding persistent atrial fibrillation (AF), and compared this with an established standard method using the cryoballoon (CB)., Methods: A total of 35 patients with symptomatic persistent AF underwent LB ablation and were followed-up for 1 year. Results were compared to 35 patients who underwent CB ablation at the same institution and case matched for age, sex, CHA 2 DS 2 -VASc score, and left atrial volume., Results: Complete isolation of all PVs was achieved in 68.6% in the LB and 97.1% in the CB group (P < 0.01). No significant differences were found for AF-free survival after 12 months in the complete cohort of all patients (LB: 53.3% vs CB: 70.4%; P = n.s.) and after excluding patients without complete PVI (LB: 57.8% vs CB: 72.5%; P = n.s.). LB ablation resulted in longer procedure (158.5 ± 37.9 minutes vs 110.9 ± 26.5 minutes; P < 0.01) and fluoroscopy durations (28.4 ± 11.1 minutes vs 23.5 ± 9.4 minutes; P = 0.04.), and a trend toward more major complications (14.3% vs 2.9%; P = n.s.). Procedure durations and complications declined over time and were level with CB-treated patients when reaching the last quartile of the LB patients., Conclusion: PVI in patients with persistent AF using the LB or the CB resulted in comparable success rates. Initial prolongations in procedure and safety parameters as a result of a learning curve effect for the LB have to be considered before starting to use this technique., (© 2016 Wiley Periodicals, Inc.)

Oral anticoagulation treatment following clinically successful catheter ablation of atrial fibrillation is controversial. Recent guidelines recommend continuation of oral anticoagulation in all patients with CHA2DS2VASc score ≥ 2 even if there is no evidence of recurrent atrial fibrillation. Due to lack of prospective data, the net clinical benefit of oral anticoagulation after successful ablation in these patients is unclear. As oral anticoagulation bears the risk of severe bleeding events, the ODIn-AF study aims to evaluate the effect of oral anticoagulation on the incidence of silent cerebral embolic events in patients with a high risk for embolic events, but free from symptomatic atrial fibrillation after successful pulmonary vein ablation.

Introduction: Right phrenic nerve palsy (PNP) is a typical complication of cryoballoon ablation of the right-sided pulmonary veins (PVs). Phrenic nerve function can be monitored by palpating the abdomen during phrenic nerve pacing from the superior vena cava (SVC pacing) or by fluoroscopy of spontaneous breathing. We sought to compare the sensitivity of these 2 techniques during cryoballoon ablation for detection of PNP., Methods and Results: A total of 133 patients undergoing cryoballoon ablation were monitored with both SVC pacing and fluoroscopy of spontaneous breathing during ablation of the right superior PV. PNP occurred in 27/133 patients (20.0%). Most patients (89%) had spontaneous recovery of phrenic nerve function at the end of the procedure or on the following day. Three patients were discharged with persistent PNP. All PNP were detected first by fluoroscopic observation of diaphragm movement during spontaneous breathing, while diaphragm could still be stimulated by SVC pacing. In patients with no recovery until discharge, PNP occurred at a significantly earlier time (86 ± 34 seconds vs. 296 ± 159 seconds, P < 0.001). No recovery occurred in 2/4 patients who were ablated with a 23 mm cryoballoon as opposed to 1/23 patients with a 28 mm cryoballoon (P = 0.049)., Conclusion: Fluoroscopic assessment of diaphragm movement during spontaneous breathing is more sensitive for detection PNP as compared to SVC pacing. PNP as assessed by fluoroscopy is frequent (20.0%) and carries a high rate of recovery (89%) until discharge. Early onset of PNP and use of 23 mm cryoballoon are associated with PNP persisting beyond hospital discharge., (© 2014 Wiley Periodicals, Inc.)

Purpose: Identification of reliable risk factors for recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) has important implications. Left atrial (LA) pressure is a largely observator-independent parameter that can easily be determined after transseptal puncture. The purpose of this study was to investigate the predictive value of LA pressure for AF recurrence after PVI., Methods: Two hundred five consecutive patients with paroxysmal or persistent AF scheduled for first PVI were included. Baseline clinical data were collected. During PVI, LA pressure was determined invasively after transseptal puncture. PVI was performed with radiofrequency or cryoenergy, and patients were followed for 25 ± 7 months., Results: One hundred five (51 %) patients had AF recurrence. Patients with persistent AF prior to ablation had significantly more recurrences than patients with paroxysmal AF (70.1 vs. 42.0 %, p < 0.001). Mean LA pressure was significantly higher in patients with recurrence of AF (13.4 ± 7.1 vs. 11.0 ± 5.2 mmHg, p = 0.007), as was mean LA volume index (40.1 ± 18.5 vs. 33.0 ± 11.2 mL/m(2), p < 0.001). In the multivariate analysis, mean LA pressure was predictive in patients with normal or mildly enlarged LA, while AF type was not predictive. For each 1-mmHg increase in LA pressure, the risk of AF recurrence increased by 11 % in this subgroup. In patients with moderately or severely enlarged LA, AF type was predictive whereas LA pressure was not., Conclusion: LA pressure, AF type, and LA volume index are independent predictors for recurrence of AF after PVI. LA pressure may be helpful especially in patients with small atria, where AF type is not predictive.

Introduction: In order to optimize power delivery into the myocardium during radiofrequency ablation (RFA) without overheating the electrode tip, active cooling of the tip electrode as well as electrode tips made of gold have evolved. Recently, an externally irrigated gold tip electrode ablation catheter has been developed to combine the advantages of these 2 technologies. We sought to investigate the procedural parameters tip temperature, delivered power and cooling flow requirements of the irrigated gold tip catheter in comparison to the conventional irrigated platinum iridium (Pt) tip catheter in pulmonary vein isolation (PVI) and cavotricuspid isthmus (CTI) ablation., Methods and Results: Sixty patients referred for first PVI were randomized into ablation with irrigated gold tip catheter versus irrigated Pt tip catheter. Forty-nine patients received ablation of CTI following PVI. Mean and standard deviation from all measurements were calculated for each patient. During RFA of pulmonary veins, mean catheter tip temperature was significantly lower in the gold group (35.4 ± 0.9 °C vs 38.2 ± 0.8 °C, P < 0.001), and total amount of delivered energy was higher (1303.1 ± 81.1 W vs 1223.7 ± 115.6 W, P = 0.004). During CTI ablation, necessary saline flow was almost 2.5-fold lower in the gold group (22.5 ± 5.9 mL/min vs 52.5 ± 9.7 mL/min, P < 0.001), accompanied by significantly lower tip temperature (39.1 ± 0.6 °C vs 40.5 ± 1.4 °C, P < 0.001)., Conclusion: The irrigated gold tip electrode allows to deliver significantly more energy at a lower electrode tip temperature in RFA of PV and CTI in comparison to the irrigated Pt tip electrode. The required saline flow during CTI ablation is much lower than in Pt., (© 2012 Wiley Periodicals, Inc.)

Aims: Left atrial catheter ablation of the pulmonary veins (PV) has evolved as an important therapeutic option for the treatment of atrial fibrillation (AF). We aimed to investigate the incidence and predictors of silent cerebral embolism associated with PV catheter ablation, detected by diffusion-weighted magnetic resonance imaging (DW-MRI)., Methods and Results: We performed a prospective analysis of 53 consecutive patients with persistent or paroxysmal AF that underwent PV ablation and post-procedural cerebral MRI 1 day after lasso catheter-guided ostial PV ablation. Patients were analysed for possible demographical, medical, echocardiographical, and procedural predictors of embolic events. A mean of 3.5 +/- 0.5 PVs were ablated per patient. In six patients, DW-MRI depicted new clinically silent microembolism after PV ablation (11%). The number of ineffective medical antiarrhythmic agents prior to ablation procedure was significantly higher in the embolism group (3.3 +/- 0.5 vs. 2.2 +/- 1.4, P = 0.014). Coronary heart disease (CAD) was more frequent in patients with cerebral embolisms (33 vs. 2%, P = 0.031); left ventricular volume (130 +/- 12 vs. 103 +/- 26 mL, P = 0.002), and septal wall thickness (13.0 +/- 1.4 vs. 7.9 +/- 4.8 mm, P = 0.025) were significantly increased., Conclusion: This study shows a high incidence of silent micro-embolic events after PV ablation. CAD, left ventricular dilatation, and hypertrophy were potential predictors of this complication.

Introduction: Ablation of pulmonary veins (PV) is an established therapeutic option for patients with symptomatic drug-refractory paroxysmal atrial fibrillation (AF). Radiofrequency (RF) is currently the most widespread energy source for PV ablation. Cryothermal energy applied with a cryoballoon technique as an alternative has recently evolved., Methods and Results: In a case-control setting, we compared 20 patients with paroxysmal AF who underwent their first PV ablation with the cryoballoon technique to 20 matched patients with conventional RF ablation. In the case of persistent electrical potentials after cryoballoon ablation, it was combined with ablation with a conventional cryocatheter. All patients performed daily event recording for 3 months after ablation procedure. Ablation parameters and success rate after 3 and 6 months were compared. In the cryoballoon group, the overall success rate was 55% (50% in the cryoballoon only group [14 patients] and 66% in the combination group [6 patients]), as opposed to the RF group with 45%. AF episode burden was lower after cryoballoon ablation. There was no significant difference between cryoballoon and RF ablation regarding procedure parameters. In the cryoballoon group, 3 phrenic nerve palsies occurred using the 23 mm balloon that resolved spontaneously., Conclusion: PV ablation with the cryoballoon technique is feasible and seems to have a similar success rate in comparison to RF ablation. Procedure- and fluoroscopy duration are not longer than in conventional RF ablation.

Background: Patients with atrial fibrillation (AF) often exhibit abnormalities of P wave morphology during sinus rhythm. We examined a novel method for automatic P wave analysis in the 24-hour-Holter-ECG of 60 patients with paroxysmal or persistent AF and 12 healthy subjects., Methods: Recorded ECG signals were transferred to the analysis program where 5-10 P and R waves were manually marked. A wavelet transform performed a time-frequency decomposition to train neural networks. Afterwards, the detected P waves were described using a Gauss function optimized to fit the individual morphology and providing amplitude and duration at half P wave height., Results: >96% of P waves were detected, 47.4 +/- 20.7% successfully analyzed afterwards. In the patient population, the mean amplitude was 0.073 +/- 0.028 mV (mean variance 0.020 +/- 0.008 mV(2)), the mean duration at half height 23.5 +/- 2.7 ms (mean variance 4.2 +/- 1.6 ms(2)). In the control group, the mean amplitude (0.105 +/- 0.020 ms) was significantly higher (P < 0.0005), the mean variance of duration at half height (2.9 +/- 0.6 ms(2)) significantly lower (P < 0.0085)., Conclusions: This method shows promise for identification of triggering factors of AF.

Cardioversion of atrial fibrillation as an element of rhythm control strategy is indicated in patients with first episode of atrial fibrillation, hemodynamic instability, recurrent atrial fibrillation with low probability of spontaneous conversion, or severe symptoms. Early cardioversion is performed within 48 h of onset of atrial fibrillation. The best point in time is still unknown. It can be performed by pharmacological, or, preferentially, by electrical cardioversion. The advantages of electrical cardioversion are higher efficacy and no proarrhythmic risk, however, short time general anaesthesia is needed. Electrical cardioversion is most effective when biphasic shocks are delivered. For pharmacological cardioversion, several antiarrhythmic drugs are available which have to be considered individually. Thromboembolic risk does not differ between the two methods. Early cardioversion and maintenance of sinus rhythm is most effective in atrial fibrillation of short duration, normal left atrial size and no or only mild structural heart disease.

Objectives: The VIP registry investigated the efficacy of preventive pacing algorithm selection in reducing atrial fibrillation (AF) burden., Background: There are few data identifying which patients might benefit most from which preventive pacing algorithms., Methods: Patients, with at least one documented AF episode and a conventional antibradycardia indication for pacemaker therapy, were enrolled. They received pacemakers with AF diagnostics and four preventive algorithms (Selection and PreventAF series, Vitatron). A 3-month Diagnostic Phase with conventional pacing identified a Substrate Group (>70% of AF episodes with <2 premature atrial contractions [PACs] before AF onset) and a Trigger Group (< or =70% of AF episodes with <2 PACs before AF onset). This was followed by a 3-month Therapeutic Phase where in the Trigger Group algorithms were enabled aimed at avoiding or preventing a PAC and in the Substrate Group continuous atrial overdrive pacing was enabled., Results: One hundred and twenty-six patients were evaluated. In the Trigger Group (n = 73), there was a statistically significant 28% improvement in AF burden (median AF burden: 2.06 hours/day, Diagnostic Phase vs 1.49 hours/day, Therapy Phase; P = 0.03304 signed-rank test), and reduced PAC activity. There was no significant improvement in AF burden in the Substrate Group (median AF burden: 1.82 hours/day, Diagnostic Phase vs 2.38 hours/day, Therapy Phase; P = 0.12095 signed-rank test), and little change in PAC activity., Conclusions: We identified a subgroup of patients for whom the selection of appropriate pacing algorithms, based on individual diagnostic data, translated into a reduced AF burden. Trigger AF patients were more likely responders to preventive pacing algorithms as a result of PAC suppression.