Safety and Effectiveness of Pulsed Field Ablation to Treat Atrial Fibrillation: One-Year Outcomes From the MANIFEST-PF Registry.

BACKGROUND: Pulsed field ablation is a novel nonthermal cardiac ablation modality using ultra-rapid electrical pulses to cause cell death by a mechanism of irreversible electroporation. Unlike the traditional ablation energy sources, pulsed field ablation has demonstrated significant preferentiality to myocardial tissue ablation, and thus avoids certain thermally mediated complications. However, its safety and effectiveness remain unknown in usual clinical care. METHODS: MANIFEST-PF (Multi-National Survey on the Methods, Efficacy, and Safety on the Post-Approval Clinical Use of Pulsed Field Ablation) is a retrospective, multinational, patient-level registry wherein patients at each center were prospectively included in their respective center registries. The registry included all patients undergoing postapproval treatment with a multielectrode 5-spline pulsed field ablation catheter to treat atrial fibrillation (AF) between March 1, 2021, and May 30, 2022. The primary effectiveness outcome was freedom from clinical documented atrial arrhythmia (AF/atrial flutter/atrial tachycardia) of ≥30 seconds on the basis of electrocardiographic data after a 3-month blanking period (on or off antiarrhythmic drugs). Safety outcomes included the composite of acute (<7 days postprocedure) and latent (>7 days) major adverse events. RESULTS: At 24 European centers (77 operators) pulsed field ablation was performed in 1568 patients with AF: age 64.5±11.5 years, female 35%, paroxysmal/persistent AF 65%/32%, CHA2DS2-VASc 2.2±1.6, median left ventricular ejection fraction 60%, and left atrial diameter 42 mm. Pulmonary vein isolation was achieved in 99.2% of patients. After a median (interquartile range) follow-up of 367 (289-421) days, the 1-year Kaplan-Meier estimate for freedom from atrial arrhythmia was 78.1% (95% CI, 76.0%-80.0%); clinical effectiveness was more common in patients with paroxysmal AF versus persistent AF (81.6% versus 71.5%; P=0.001). Acute major adverse events occurred in 1.9% of patients. CONCLUSIONS: In this large observational registry of the postapproval clinical use of pulsed field technology to treat AF, catheter ablation using pulsed field energy was clinically effective in 78% of patients with AF.

Impact of Comorbid Sleep-Disordered Breathing and Atrial Fibrillation on the Long-Term Outcome After Ischemic Stroke.

BACKGROUND: Sleep-disordered breathing (SDB) and atrial fibrillation (AF) are highly prevalent in patients with stroke and are recognized as independent risk factors for stroke. Little is known about the impact of comorbid SDB and AF on long-term outcomes after stroke. METHODS: In this prospective cohort study, 353 patients with acute ischemic stroke or transient ischemic attacks were analyzed. Patients were screened for SDB by respiratory polygraphy during acute hospitalization. Screening for AF was performed using a 7-day ECG up to 3× in the first 6 months. Follow-up visits were scheduled at 1, 3, 12, 24, and 36 months poststroke. Cox regression models adjusted for various factors (age, sex, body mass index, hypertension, diabetes, dyslipidemia, and heart failure) were used to assess the impact of comorbid SDB and AF on subsequent death or cerebro-cardiovascular events. RESULTS: Among 353 patients (299 ischemic stroke and 54 transient ischemic attacks), median age, 67 (interquartile range, 57-74) years with 63% males. Moderate-to-severe SDB (apnea-hypopnea index score, ≥15/h) was present in 118 (33.4%) patients. Among the 56 (15.9%) patients with AF, 28 had comorbid moderate-to-severe SDB and AF. Over 36 months, there were 12 deaths and 67 recurrent cerebro-cardiovascular events. Patients with comorbid moderate-to-severe SDB and AF had a higher risk of subsequent death or cerebro-cardiovascular events compared with those with only moderate-to-severe SDB without AF (hazard ratio, 2.49 [95% CI, 1.18-5.24]) and to those without moderate-to-severe SDB or AF (hazard ratio, 2.25 [95% CI, 1.12-4.50]). However, no significant difference was found between the comorbid moderate-to-severe SDB and AF group and the group with only AF without moderate-to-severe SDB (hazard ratio, 1.64 [95% CI, 0.62-4.36]). CONCLUSIONS: Comorbid moderate-to-severe SDB and AF significantly increase the risk of long-term mortality or recurrent cerebro-cardiovascular events after acute ischemic stroke. Considering both conditions as cumulative and modifiable cerebro-cardiovascular risk factors is of interest for the management of acute stroke. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02559739.

Epicardial adipose tissue dispersion at CT and recurrent atrial fibrillation after pulmonary vein isolation.

OBJECTIVES: Epicardial adipose tissue (EAT) remodeling is associated with atrial fibrillation (AF). Left atrial (LA) EAT dispersion on cardiac CT is a non-invasive imaging biomarker reflecting EAT heterogeneity. We aimed to investigate the association of LA EAT dispersion with AF recurrence after pulmonary vein isolation (PVI). METHODS: In a prospective registry of consecutive patients undergoing first PVI, mean EAT attenuation values were measured on contrast-enhanced cardiac CT scans in Hounsfield units (HU) within low (- 195 to - 45 HU) and high (- 44 to - 15 HU) threshold EAT compartments around the left atrium (LA). EAT dispersion was defined as the difference between the mean HU values within the two EAT compartments. Continuous variables were compared between groups using the Mann-Whitney U test and cox proportional hazard models were used to calculate hazard ratios of predictors of 1-year AF recurrence. RESULTS: A total of 208 patients were included, 135 with paroxysmal AF and 73 with persistent AF. LA EAT dispersion was significantly larger in patients with persistent compared to paroxysmal AF (52.6 HU vs. 49.9 HU; p = 0.001). After 1 year of follow-up, LA EAT dispersion above the mean (> 50.8 HU) was associated with a higher risk of AF recurrence (HR 2.3, 95% CI 1.5-3.6; p < 0.001). It retained its predictive value when corrected for age, sex, body mass index, LA volume, and AF type (HR 2.8, 95% CI 1.6-4.6; p < 0.001). CONCLUSION: A larger LA EAT dispersion on contrast-enhanced cardiac CT scans, reflecting EAT heterogeneity, is independently associated with AF recurrence after PVI. CLINICAL RELEVANCE STATEMENT: Based on LA EAT dispersion assessment, a more accurate risk stratification and patient selection may be possible based on a pre-procedural cardiac CT when planning PVI. KEY POINTS: • Epicardial adipose tissue (EAT) remodeling is associated with atrial fibrillation (AF). • A larger left atrial EAT dispersion in a pre-procedural cardiac CT was associated with a higher 1-year AF recurrence risk after pulmonary vein isolation. • A pre-procedural cardiac CT with left atrial EAT dispersion assessment may provide a more accurate risk stratification and patient selection for PVI.

Feasibility study on atrial fibrillation ablation with pulsed field ablation and concomitant occlusion of the left atrial appendage.

AIMS: Atrial fibrillation (AF) ablation and left atrial appendage occlusion (LAAO) are increasingly performed as individual procedures. Pulsed field ablation (PFA) has significantly reduced procedure duration and may be advantageous for the combined approach. METHODS AND RESULTS: We have launched a programme for simultaneous AF ablation using PFA and LAAO for patients qualifying for both treatments and excluding those with a complex anatomy. We compare procedure duration and fluoroscopy time against individual procedures (either AF ablation or LAAO alone), all performed by the same operators and using consistent technologies. We performed the combined procedure in 10 patients (50% males; median age 70 years) and excluded 2 patients (17%) because of a complex left atrial appendage anatomy. No death, stroke, or major bleeding events, including pericardial effusion, occurred. For single-procedure comparison, 207 AF ablation procedures and 61 LAAO procedures were available. The total median procedure duration was 79 min (range 60-125) for the combined procedure, 71 min (25-241) for individual AF ablation (51 min without and 78 min with 3-dimensional electroanatomic mapping), and 47 min (15-162) for individual LAAO. The respective fluoroscopy times were 21 (15-26), 15 (5-44), and 10 (3-50) min. For the combined procedure, femoral vein access to last PFA application lasted 49 min (34-93) and LAAO added 20 min (15-37). CONCLUSION: Simultaneous PFA-based AF ablation and LAAO in carefully selected patients is feasible and safe and can be executed within a short overall procedure duration.

Strategies to improve atrioventricular synchrony in patients with a Micra AV leadless pacemaker.

The second generation of transcatheter pacing systems, called Micra AV, can provide atrioventricular (AV) synchronous pacing via a new pacing algorithm relying on sensing mechanical atrial contraction. Several novel programming parameters were introduced to enable AV synchronous pacing, including an A3 window and A4 window as well as a conduction mode switch and an activity mode switch. In addition to several automated features, manual programming optimization of some of the novel parameters is key to improving AV synchrony. A solid knowledge of the features and their programming is essential for electrophysiologists implanting or following patients with Micra AV devices. Differences in programming optimization might partially explain the high variability of AV synchrony published in real-world data reports. This article reviews the key programming parameters of Micra AV. Subsequently, optimal programming recommendations for defined patient profiles are presented. Those were established by consensus within an expert panel comprised of 11 European electrophysiologists from high-volume Micra AV centres. The patient profiles were (1) high degree AV block and slow sinus rhythm; (2) high degree AV block and fast sinus rhythm; and (3) intermittent AV block. The panel recommended to evaluate the mechanical atrial activity on transthoracic echocardiography prior to implant. It was also agreed that Auto A3 Threshold and Tracking Check should be turned off in all patients, AV conduction mode switch should be turned off in all patients with high degree AV block, and the lower rate should be programmed to 50 bpm with exceptions based on individual clinical assessment. Future studies will be useful to evaluate the strength of those recommendations to improve the AV synchrony.

Impact of atrial fibrillation phenotype and left atrial volume on outcome after pulmonary vein isolation.

AIMS: Pulmonary vein isolation (PVI) is increasingly performed in patients with atrial fibrillation (AF). Both AF phenotype and left atrial (LA) volume have been shown to influence ablation outcome. The inter-relationship of the two is incompletely understood. We aimed to investigate the impact of AF phenotype vs. LA volume on outcome after PVI. METHODS AND RESULTS: In a retrospective analysis of a prospective registry of patients undergoing a first PVI, the association of AF phenotype and LA volume index (LAVI) was assessed as well as their impact on AF recurrence during follow-up. Overall, 476 patients were enrolled (median age 63 years, 29% females, 65.8% paroxysmal AF). Obesity, hypertension, chronic kidney disease, and heart failure were all significantly more frequent in persistent AF. After 1 year, single-procedure, freedom from arrhythmia recurrence was 61.5%. Patients with paroxysmal AF had better outcomes compared with patients with persistent AF (65.6 vs. 52.7%, P = 0.003), as had patients with no/mild vs. moderate/severe LA dilation (LAVI <42 mL/m2 67.1% vs. LAVI ≥42 mL/m2 53%, P < 0.001). The combination of both parameters refined prediction of 1-year recurrence (P < 0.001). After adjustment for additional clinical risk factors in multivariable Cox proportional hazard analysis, both AF phenotype and LAVI ≥42 mL/m2 contributed significantly towards the prediction of 1-year recurrence. CONCLUSION: Atrial fibrillation phenotype and LA volume are independent predictors of outcome after PVI. Persistent AF with no/mild LA dilation has a similar risk of recurrence as paroxysmal AF with a moderate/severe LA dilation and should be given similar priority for ablation.

Long-term outcomes of the pentaspline pulsed-field ablation catheter for the treatment of paroxysmal atrial fibrillation: results of the prospective, multicentre FARA-Freedom Study.

AIMS: Pulmonary vein isolation (PVI) is a well-established strategy for the treatment of paroxysmal atrial fibrillation (PAF). Despite randomized controlled trials and real-world data showing the promise of pulsed-field ablation (PFA) for this treatment, long-term efficacy and safety data demonstrating single-procedure outcomes off antiarrhythmic drugs remain limited. The aim of the FARA-Freedom Study was to evaluate the long-term efficacy and safety of PFA using the pentaspline catheter for PAF. METHODS AND RESULTS: FARA-Freedom, a prospective, non-randomized, multicentre study, enrolled patients with PAF undergoing de novo PVI with PFA, who were followed for 12 months with weekly transtelephonic monitoring and a 72-h Holter ECG at 6 and 12 months. The primary safety endpoint was a composite of device- or procedure-related serious adverse events out to 7 days post-ablation and PV stenosis or atrioesophageal (AE) fistula out to 12 months. Treatment success is a composite of acute PVI and chronic success, which includes freedom from any documented atrial tachyarrhythmia longer than 30 s, use of antiarrhythmic drugs or cardioversion after a 3-month blanking period, or use of amiodarone or repeat ablation at any time. The study enrolled 179 PAF patients (62 ± 10 years, 39% female) at 13 centres. At the index procedure, all PVs were successfully isolated with the pentaspline PFA catheter. Procedure and left atrial dwell times, with a 20-min waiting period, were 71.9 ± 17.6 and 41.0 ± 13.3 min, respectively. Fluoroscopy time was 11.5 ± 7.4 min. Notably, monitoring compliance was high, with 88.4 and 90.3% with weekly events and 72-h Holter monitors, respectively. Freedom from the composite primary effectiveness endpoint was 66.6%, and 41 patients had atrial tachyarrhythmia recurrence, mostly recurrent atrial fibrillation (31 patients). The composite safety endpoint occurred in two patients (1.1%), one tamponade and one transient ischaemic attack. There was no coronary spasm, PV stenosis, or AE fistula. There were four cases of transient phrenic nerve palsy, but all resolved during the index procedure. CONCLUSION: In this prospective, non-randomized, multicentre study, PVI using a pentaspline PFA catheter was effective in treating PAF patients despite rigourous endpoint definitions and high monitoring compliance and demonstrated favourable safety. REGISTRATION: Clinical Trials.gov Identifier: NCT05072964 (sponsor: Boston Scientific Corporation).

Bipolar Radiofrequency Ablation of Refractory Ventricular Arrhythmias: Results from a Multicenter Network.

BACKGROUND: Advanced ablation strategies are needed to treat ventricular tachycardia (VT) and premature ventricular contractions (PVC) refractory to standard unipolar radiofrequency ablation (Uni-RFA). Bipolar radiofrequency catheter ablation (Bi-RFA) has emerged as a treatment option for refractory VT, PVC. Multicenter registry data on the use of Bi-RFA in the setting of refractory VT and PVC are lacking. PURPOSE: The aim of this Bi-RFA registry is to determine its real-world safety, feasibility, and efficacy in patients with refractory VT/PVC. METHODS: Consecutive patients undergoing Bi-RFA at sixteen European centers for recurring VT/PVC after at least one standard Uni-RFA were included. Second ablation catheter was used instead of a dispersive patch and was positioned at the opposite site of the ablation target. RESULTS: Between March 2021 and August 2024, ninety-one patients underwent 94 Bi-RFA procedures (74 males, age 62±13, prior Uni-RFA range 1-8). Indications were recurrence of PVC (n=56), VT (n=20), electrical storm (n=13), or PVC-triggered ventricular fibrillation (n=2). Procedural time was 160±73min, Bi-RFA time 426±286s, mean Uni-RFA time 819±697s. Elimination of clinical VT/PVC was achieved in 67 (74%) patients, suppression of VT/PVC in a further 10 (11%) patients. In the remaining 14 patients (15%) no effect on VT/PVC was observed. Three major complications occurred: coronary artery occlusion, AV block and arteriovenous fistula. Follow-up lasted 7±8 months. Nineteen (61%) remained VT-free. ≥80% PVC burden reduction was achieved in 45 (78%). CONCLUSIONS: This real-world registry data indicates that Bi-RFA appears safe, is feasible, and effective in the majority of patients with VT/PVC.

2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation.

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society .

Patient characteristics, predictors and outcome of pacemaker patients upgraded to an implantable cardioverter defibrillator.

AIMS: Pacemaker (PM) patients may require a subsequent upgrade to an implantable cardioverter defibrillator (ICD). Limited data exists on this patient population. We sought to characterize this population, to assess predictors for ICD upgrade, and to report the outcome. METHODS: From our prospective PM and ICD implantation registry, all patients who underwent PM and/or ICD implantations at our center were analyzed. Patient characteristics and outcomes of PM patients with subsequent ICD upgrade were compared to age- and sex-matched patients with de novo ICD implantation, and to PM patients without subsequent upgrade. RESULTS: Of 1'301 ICD implantations, 60 (5%) were upgraded from PMs. Median time from PM implantation to ICD upgrade was 2.6 years (IQR 1.3-5.4). Of 2'195 PM patients, 28 patients underwent subsequent ICD upgrades, corresponding to an estimated annual incidence of an ICD upgrade of at least 0.33%. Lower LVEF (p = .05) and male sex (p = .038) were independent predictors for ICD upgrade. Survival without death, transplant and LVAD implantation were worse both for upgraded ICD patients compared to matched patients with de novo ICD implantation (p = .05), as well as for PM patients with subsequent upgrade compared to matched PM patients not requiring an upgrade (p = .036). CONCLUSIONS: One of 20 ICD implantations are upgrade of patients with a PM. At least one of 30 PM patients will require an ICD upgrade in the following 10 years. Predictors for ICD upgrade are male sex and lower LVEF at PM implantation. Upgraded patients have worse outcomes.

Electrophysiological differences of randomized deep sedation with dexmedetomidine versus propofol.

BACKGROUND: Dexmedetomidine and propofol are common sedatives in intensive care units and for interventional procedures. Both may compromise sinus node function and atrioventricular conduction. The objective of this prospective, randomized study is to compare the effect of dexmedetomidine with propofol on sinus node function and atrioventricular conduction. METHODS: In a tertiary care center in Switzerland we included from September 2019 to October 2020 160 patients (65 ± 11 years old; 32% female) undergoing first ablation for atrial fibrillation by cryoballoon ablation or by radiofrequency ablation. Patients were randomly assigned to deep sedation with dexmedetomidine (DEX group) versus propofol (PRO group). A standard electrophysiological study was performed after pulmonary vein isolation with the patients still deeply sedated and hemodynamically stable. RESULTS: Eighty patients each were randomized to the DEX and PRO group. DEX group patients had higher baseline sinus cycle length (1022 vs. 1138 ms; p = 0.003) and longer sinus node recovery time (SNRT400; 1597 vs. 1412 ms; p = 0.042). However, both corrected SNRT and normalized SNRT did not differ. DEX group patients had longer PR interval (207 vs. 186 ms; p = 0.002) and AH interval (111 vs. 95 ms, p = 0.008), longer Wenckebach cycle length of the atrioventricular node (512 vs. 456 ms; p = 0.005), and longer atrioventricular node effective refractory period (390 vs. 344 ms; p = 0.009). QRS width and HV interval were not different. An arrhythmia, mainly atrial fibrillation, was induced in 33 patients during the electrophysiological study, without differences among groups (20% vs. 15%, p = 0.533). CONCLUSIONS: Dexmedetomidine has a more pronounced slowing effect on sinus rate and suprahissian AV conduction than propofol, but not on infrahissian AV conduction and ventricular repolarization. These differences need to be taken into account when using these sedatives. TRIAL REGISTRATION: ClinicalTrials.gov number NCT03844841, 19/02/2019.

Biomarker, Imaging, and Clinical Factors Associated With Overt and Covert Stroke in Patients With Atrial Fibrillation.

BACKGROUND: Atrial fibrillation is a major risk factor for stroke and silent brain infarcts. We studied whether a multimodal approach offers additional insights to the CHA2DS2-VASc score in predicting stroke or new brain infarcts on magnetic resonance imaging (MRI) over a 2-year follow-up. METHODS: Swiss-AF is a prospective, multicenter cohort study of patients with known atrial fibrillation. We included patients with available brain MRI both at enrollment and 2 years later. The dates of the baseline and follow-up visits ranged from March 2014 to November 2020. The primary outcome was assessed 2 years after baseline and was defined as a composite of clinically identified stroke or any new brain infarct on the 2-year MRI. We compared a multivariable logistic regression model including prespecified clinical, biomarker, and baseline MRI variables to the CHA2DS2-VASc score. RESULTS: We included 1232 patients, 89.8% of them taking oral anticoagulants. The primary outcome occurred in 78 patients (6.3%). The following baseline variables were included in the final multivariate model and were significantly associated with the primary outcome: white matter lesion volume in milliliters (adjusted odds ratio [aOR], 1.91 [95% CI, 1.45-2.56]), NT-proBNP (N-terminal pro-B-type natriuretic peptide; aOR, 1.75 [95% CI, 1.20-2.63]), GDF-15 (growth differentiation factor-15; aOR, 1.68 [95% CI, 1.11-2.53]), serum creatinine (aOR, 1.50 [95% CI, 1.02-2.22]), IL (interleukin)-6 (aOR, 1.37 [95% CI, 1.00-1.86]), and hFABP (heart-type fatty acid-binding protein; aOR, 0.48 [95% CI, 0.31-0.73]). Overall performance and discrimination of the new model was superior to that of the CHA2DS2-VASc score (C statistic, 0.82 [95% CI, 0.77-0.87] versus 0.64 [95% CI, 0.58-0.70]). CONCLUSIONS: In patients with atrial fibrillation, a model incorporating white matter lesion volume on baseline MRI and selected blood markers yielded new insights on residual stroke risk despite a high proportion of patients on oral anticoagulants. This may be relevant to develop further preventive measures.

Pulsed-field-ablation for the treatment of atrial fibrillation in patients with congenital anomalies of cardiac veins.

INTRODUCTION: Anomalous cardiac veins are not rare and pulmonary vein (PV) isolation for atrial fibrillation (AF) treatment should include these veins. Pulsed-field ablation (PFA) is a novel technology for AF ablation with excellent efficacy and safety profile. In this case series, we describe our first experience of isolation of anomalous cardiac veins using PFA in patients with AF. METHODS: We report a series of patients with congenital anomalies of the cardiac veins and AF, treated with PFA. All patients underwent cardiac computed tomography for procedural planning. RESULTS: We included five patients (four males). Anomalous cardiac veins included a connection of a left common ostium to the coronary sinus, a partial and complete drainage of the right superior PV into the superior vena cava (SVC) with and without additional atrial septal defect, a persistent left SVC and an anomalous posterior PV. All anomalous PVs were isolated using PFA. No phrenic nerve palsy or other complications occurred. PFA of an abnormal right superior PV draining into the distal SVC was possible without affecting the sinus node. After a median of 4 months, four patients were free of recurrence. One patient had recurrent AF and perimitral reentry tachycardia, probably facilitated by PFA in the mitral isthmus region during isolation of an anomalous connection of the left common ostium to the coronary sinus. CONCLUSIONS: Using systematic preprocedural imaging and three-dimensional-electroanatomic mapping, the currently available PFA system seems well suited, efficient, and versatile for the treatment of AF in patients with anomalous cardiac veins.

Validation of the accuracy of contact force measurement by contemporary force-sensing ablation catheters.

INTRODUCTION: Contact force sensing catheters are widely used for ablation of cardiac arrhythmias. They allow quantification of catheter-to-tissue contact, which is an important determinant for lesion formation and may reduce the risk of complications. The accuracy of these sensors may vary across the measurement range, catheter-to-tissue angle, and amongst manufacturers. We aim to compare the accuracy and reproducibility of four different force sensing ablation catheters. METHODS: A measurement setup containing a heated saline water bath with an integrated force measurement unit was constructed and validated. Subsequently, we investigated four different catheter models, each equipped with a unique measurement technology: Tacticath Quartz (Abbott), AcQBlate Force (Biotronik/Acutus), Stablepoint (Boston Scientific), and Smarttouch SF (Biosense Webster). For each model, the accuracy of three different catheters was measured within the range of 0-60 g and at contact angles of 0°, 30°, 45°, 60°, and 90°. RESULTS: In total, 6685 measurements were performed using 4 × 3 catheters (median of 568, interquartile range: 511-606 measurements per catheter). Over the entire measurement-range, the force measured by the catheters deviated from the real force by the following absolute mean values: Tacticath 1.29 ± 0.99 g, AcQBlate Force 2.87 ± 2.37 g, Stablepoint 1.38 ± 1.29 g, and Smarttouch 2.26 ± 2.70 g. For some models, significant under- and overestimation of >10 g were observed at higher forces. Mean absolute errors of all models across the range of 10-40 g were <3 g. CONCLUSION: Contact measured by force-sensing catheters is accurate with 1-3 g deviation within the range of 10-40 g. Significant errors can occur at higher forces with potential clinical consequences.

Effect of contact force on pulsed field ablation lesions in porcine cardiac tissue.

INTRODUCTION: Contact force has been used to titrate lesion formation for radiofrequency ablation. Pulsed field ablation (PFA) is a field-based ablation technology for which limited evidence on the impact of contact force on lesion size is available. METHODS: Porcine hearts (n = 6) were perfused using a modified Langendorff set-up. A prototype focal PFA catheter attached to a force gauge was held perpendicular to the epicardium and lowered until contact was made. Contact force was recorded during each PFA delivery. Matured lesions were cross-sectioned, stained, and the lesion dimensions measured. RESULTS: A total of 82 lesions were evaluated with contact forces between 1.3 and 48.6 g. Mean lesion depth was 4.8 ± 0.9 mm (standard deviation), mean lesion width was 9.1 ± 1.3 mm, and mean lesion volume was 217.0 ± 96.6 mm3 . Linear regression curves showed an increase of only 0.01 mm in depth (depth = 0.01 × contact force + 4.41, R2 = 0.05), 0.03 mm in width (width = 0.03 × contact force + 8.26, R2 = 0.13) for each additional gram of contact force, and 2.20 mm3 in volume (volume = 2.20 × contact force + 162, R2 = 0.10). CONCLUSION: Increasing contact force using a bipolar, biphasic focal PFA system has minimal effects on acute lesion dimensions in an isolated porcine heart model and achieving tissue contact is more important than the force with which that contact is made.

Physical activity and brain health in patients with atrial fibrillation.

BACKGROUND AND PURPOSE: Vascular brain lesions, such as ischemic infarcts, are common among patients with atrial fibrillation (AF) and are associated with impaired cognitive function. The role of physical activity (PA) in the prevalence of brain lesions and cognition in AF has not been investigated. METHODS: Patients from the multicenter Swiss-AF cohort study were included in this cross-sectional analysis. We assessed regular exercise (RE; at least once weekly) and minutes of weekly PA using a validated questionnaire. We studied associations with ischemic infarcts, white matter hyperintensities, cerebral microbleeds, and brain volume on brain magnetic resonance imaging and with global cognition measured with a cognitive construct (CoCo) score. RESULTS: Among 1490 participants (mean age = 72 ± 9 years), 730 (49%) engaged in RE. In adjusted regression analyses, RE was associated with a lower prevalence of ischemic infarcts (odds ratio [OR] = 0.78, 95% confidence interval [CI] = 0.63-0.98, p = 0.03) and of moderate to severe white matter hyperintensities (OR = 0.78, 95% CI = 0.62-0.99, p = 0.04), higher brain volume (ß-coefficient = 10.73, 95% CI = 2.37-19.09, p = 0.01), and higher CoCo score (ß-coefficient = 0.08, 95% CI = 0.03-0.12, p < 0.001). Increasing weekly PA was associated with higher brain volume (ß-coefficient = 1.40, 95% CI = 0.65-2.15, p < 0.001). CONCLUSIONS: In AF patients, RE was associated with a lower prevalence of ischemic infarcts and of moderate to severe white matter disease, with larger brain volume, and with better cognitive performance. Prospective studies are needed to investigate whether these associations are causal. Until then, our findings suggest that patients with AF should be encouraged to remain physically active.

Real-World Cost-Effectiveness of Pulmonary Vein Isolation for Atrial Fibrillation: A Target Trial Approach.

OBJECTIVES: Randomized controlled trials of pulmonary vein isolation (PVI) for treating atrial fibrillation (AF) have proven the procedure's efficacy. Studies assessing its empirical cost-effectiveness outside randomized trial settings are lacking. We aimed to evaluate the effectiveness and cost-effectiveness of PVI versus medical therapy for AF. METHODS: We followed a target trial approach using the Swiss-AF cohort, a prospective observational cohort study that enrolled patients with AF between 2014 and 2017. Resource utilization and cost information were collected through claims data. Quality of life was measured with EQ-5D-3L utilities. We estimated incremental cost-effectiveness ratios (ICERs) from the perspective of the Swiss statutory health insurance system. RESULTS: Patients undergoing PVI compared with medical therapy had a 5-year overall survival advantage with a hazard ratio of 0.75 (95% CI 0.46-1.21; P = .69) and a 19.8% SD improvement in quality of life (95% CI 15.5-22.9; P < .001), at an incremental cost of 29 604 Swiss francs (CHF) (95% CI 16 354-42 855; P < .001). The estimated ICER was CHF 158 612 per quality-adjusted life-year (QALY) gained within a 5-year time horizon. Assuming similar health effects and costs over 5 additional years changed the ICER to CHF 82 195 per QALY gained. Results were robust to the sensitivity analyses performed. CONCLUSIONS: Our results show that PVI might be a cost-effective intervention within the Swiss healthcare context in a 10-year time horizon, but unlikely to be so at 5 years, if a willingness-to-pay threshold of CHF 100 000 per QALY gained is assumed. Given data availability, we find target trial designs are a valuable tool for assessing the cost-effectiveness of healthcare interventions outside of randomized controlled trial settings.

Sense-B-noise: an enigmatic cause for inappropriate shocks in subcutaneous implantable cardioverter defibrillators.

AIMS: Subcutaneous implantable cardioverter defibrillators (S-ICDs) are well established. However, inappropriate shocks (IAS) remain a source of concern since S-ICDs offer very limited troubleshooting options. In our multicentre case series, we describe several patients who experienced IAS due to a previously unknown S-ICD system issue. METHODS AND RESULTS: We observed six patients suffering from this novel IAS entity. The IAS occurred exclusively in primary or alternate S-ICD sensing vector configuration (therefore called 'Sense-B-noise'). IAS were caused by non-physiologic oversensing episodes characterized by intermittent signal saturation, diminished QRS amplitudes, and disappearance of the artefacts after the IAS. Noise/oversensing could not be provoked by manipulation, X-ray did not show evidence for lead/header issues and impedance measurements were within normal limits. The pooled experience of our centres implies that up to ∼5% of S-ICDs may be affected. The underlying root cause was discussed extensively with the manufacturer but remains unknown and is under further investigation. CONCLUSION: Sense-B-noise is a novel cause for IAS due to non-physiologic signal oversensing, arising from a previously unknown S-ICD system issue. Sense-B-noise may be suspected if episodes of signal saturation in primary or alternate vector configuration are present, oversensing cannot be provoked, and X-ray and electrical measurements appear normal. The issue can be resolved by reprogramming the device to secondary sensing vector.

Eliminating transseptal sheath exchange for pulsed field ablation procedures using a direct over-the-needle transseptal access with the Faradrive sheath.

AIMS: Pulsed field ablation (PFA) for pulmonary vein isolation (PVI) combines the benefits of high procedural efficacy and safety. Transseptal puncture (TSP) to obtain left atrial (LA) access during PVI remains an important source of complications during LA procedures. For PFA procedures, TSP is generally performed using a standard transseptal sheath that is then exchanged over the wire for a dedicated PFA sheath, which might be a potential source for air embolism. We aimed to prospectively evaluate the feasibility and safety of a simplified workflow using the PFA sheath (Faradrive, Boston Scientific) directly for TSP. METHODS AND RESULTS: We prospectively enrolled 100 patients undergoing PVI using PFA at two centres. TSP was performed using the PFA sheath and a standard 98 cm transseptal needle under fluoroscopic guidance. TSP via the PFA sheath was successfully performed in all patients and no complications occurred. The median time from the first groin puncture to the completed LA access was 12 min (IQR 8-16 min). CONCLUSION: An over-the-needle TSP directly with the PFA sheath proved feasible and safe in our study. This simplified workflow has the potential to reduce the risk of air embolism, to shorten procedure time, and to reduce cost.

Posterior wall ablation by pulsed-field ablation: procedural safety, efficacy, and findings on redo procedures.

AIMS: The left atrial posterior wall is a potential ablation target in patients with recurrent atrial fibrillation despite durable pulmonary vein isolation or in patients with roof-dependent atrial tachycardia (AT). Pulsed-field ablation (PFA) offers efficient and safe posterior wall ablation (PWA), but available data are scarce. METHODS AND RESULTS: Consecutive patients undergoing PWA using PFA were included. Posterior wall ablation was performed using a pentaspline PFA catheter and verified by 3D-electroanatomical mapping. Follow-up was performed using 7-day Holter ECGs 3, 6, and 12 months after ablation. Recurrence of any atrial arrhythmia lasting more than 30 s was defined as failure. Lesion durability was assessed during redo procedures. Posterior wall ablation was performed in 215 patients (70% males, median age 70 [IQR 61-75] years, 67% redo procedures) and was successful in all patients (100%) by applying a median of 36 (IQR 32-44) PFA lesions. Severe adverse events were cardiac tamponade and vascular access complication in one patient each (0.9%). Median follow-up was 7.3 (IQR 5.0-11.8) months. One-year arrhythmia-free outcome in Kaplan-Meier analysis was 53%. A redo procedure was performed in 26 patients (12%) after a median of 6.9 (IQR 2.4-11) months and showed durable PWA in 22 patients (85%) with only minor lesion regression. Among four patients with posterior wall reconnection, three (75%) presented with roof-dependent AT. CONCLUSION: Posterior wall ablation with this pentaspline PFA catheter can be safely and efficiently performed with a high durability observed during redo procedures. The added value of durable PWA for the treatment of atrial fibrillation remains to be evaluated.