BACKGROUND:Pulsed field ablation (PFA) has emerged as a promising energy source for atrial fibrillation (AF) catheter ablation. This study aimed to describe the adoption and workflow optimization of a novel balloon-in-basket PFA catheter using a two rings balloon and pear strategy for pulmonary vein isolation (PVI), the pear workflow. METHODS:Consecutive all-comer patients with AF underwent PFA using the balloon-in-basket PFA catheter under deep sedation. The pear workflow comprised a two-step PVI protocol: (1) four antral PFA applications guided by initial PV angiography to confirm PV occlusion and lesion overlap through rotational deployment, followed by (2) two distal, pear-shaped balloon applications targeting the PV sleeves. Three-dimensional electroanatomic mapping with impedance-based contact assessment was utilized. Procedural parameters, acute efficacy, and safety were analyzed. RESULTS:Fifty patients (62% paroxysmal AF, 42% female, mean age 68 ± 10 years) were enrolled. All PVs were successfully isolated. Median procedural and fluoroscopy times were 50 min (IQR 41-50) and 7.2 min (IQR 5.8-11.4), respectively, without significant change over the study course (50 vs. 47 min for patients 1-25 and 26-50, respectively, p = 0.26). Additional ablation was performed in four patients, and concomitant left atrial appendage closure was performed in three. No major or minor complications occurred. Transient phrenic nerve stunning was observed in two patients, resolving before procedure completion. CONCLUSION:The pear two-step strategy enables rapid, efficient, and safe PVI using a balloon-in-basket PFA catheter, which, despite its anatomically based design, offers procedural versatility through integrated mapping with a minimal learning curve.
INTRODUCTION:The optimal duration of implantable loop recorder (ILR) monitoring remains uncertain and may differ according to the indication for implantation. We evaluated whether the time-dependent diagnostic yield and clinical relevance of ILR-detected arrhythmias differ among patients implanted for syncope, palpitations, cryptogenic stroke, or Brugada syndrome. OBJECTIVE:This study sought to define the time-dependent diagnostic yield of ILRs across clinical indications and to assess whether early and late diagnoses differed in their impact on clinical management. METHODS AND RESULTS:We retrospectively analyzed 1734 consecutive patients undergoing ILR implantation at 5 Italian centers for unexplained syncope, palpitations, cryptogenic stroke, or Brugada syndrome. Diagnosis of interest was defined according to the implant indication: pauses for syncope, supraventricular tachycardia or atrial fibrillation for palpitations, atrial fibrillation for cryptogenic stroke, and ventricular tachycardia or pauses for Brugada syndrome. Median follow-up was 34 months. Maximally selected rank statistics identified 26 months as the global threshold separating early from late diagnoses, while indication-specific optimal diagnostic windows were 14 months for syncope, 13 months for palpitations, 16 months for cryptogenic stroke, and 55 months for Brugada syndrome. In syncope and palpitations, most actionable diagnoses occurred early, and diagnostic efficiency declined markedly after 26 months, with late findings often less clearly related to the index presentation. In cryptogenic stroke, atrial fibrillation detection was most frequent early but could still lead to changes in antithrombotic management later, supporting an individualized "gray-zone" approach to prolonged monitoring. By contrast, Brugada syndrome showed sustained diagnostic yield over extended follow-up, with late ventricular arrhythmias or pauses retaining major prognostic and therapeutic implications, including implantable cardioverter-defibrillator implantation and device-type selection. CONCLUSIONS:The value of ILR monitoring is strongly time- and indication-dependent. Prolonged routine monitoring or reimplantation appears to have limited incremental value in syncope and palpitations when early follow-up is unrevealing, whereas extended surveillance may remain justified in Brugada syndrome and should be individualized after cryptogenic stroke. These observations support indication-driven ILR follow-up strategies rather than a uniform approach based on device longevity alone.
INTRODUCTION:Micra AV enables atrioventricular (AV)-synchronous pacing by sensing atrial mechanical contraction (A4) using device's accelerometer. Short-term studies showed good AV synchrony (AVS), but long-term data are lacking. METHODS:Within the OPTIVALL cohort, we identified patients implanted with a first-generation Micra AV (June 2020-February 2024) who remained in sinus rhythm and programmed in VDD for ≥ 1 year. Device-derived AVS was collected annually (tracking index and total AVS = AM-VP + AM-VS) up to 4 years. A4 amplitude was recorded at each visit. A subgroup underwent 24-h Holter-ECG to assess ambulatory AVS at long-term follow-up. Atrial sensing had been optimized early after implant with no further adjustment at follow-up. RESULTS:Of 54 implanted patients, 44 met inclusion criteria. Median (IQR) total AVS remained stable over time: 90.6% (85.4%-93.6%), 90.6% (83.1%-92.1%), 89.2% (84.3%-92.2%), and 89.3% (86.2%-91.6%) at 1, 2, 3, and 4 years, respectively (p = 0.789). Median (IQR) tracking index was 94.3% (88.9%-97.1%), 93.0% (85.0%-98.0%), 90.2% (84.4%-98.0%), and 90.0% (87.0%-93.9%) (p = 0.059). Median (IQR) A4 signal amplitude was 3.1 (2.0-5.1), 5.1 (2.1-5.1), 3.7 (1.9-5.1), and 5.1 (2.5-5.1) m/s2 (p = 0.993). In 20 patients with 24-h Holter-ECG at 2.7 ± 1.1 years, ambulatory AVS was 85.5% (80.0%-90.7%) and was comparable to the 3-month value (87.9% (76.8%-93.1%); p = 0.811). CONCLUSIONS:When atrial sensing is optimized early, Micra AV can provide high and stable AV-synchronous pacing for up to 4 years, with preserved A4 signal amplitude.
BACKGROUND:Landmark randomized controlled trials (RCTs) comparing left atrial appendage occlusion (LAAO) against direct oral anticoagulants (DOACs) are individually underpowered for small but clinically meaningful differences. We performed a pooled meta-analysis to provide more precise efficacy and safety data. METHODS:Utilizing random-effects models, we pooled data from 5890 patients across four landmark RCTs (PRAGUE-17, CLOSURE-AF, OPTION, and CHAMPION-AF) at their longest follow-up. RESULTS:There were no significant differences between LAAO and antithrombotics in cardiovascular mortality (5.3% vs. 4.8%, p = 0.33), all-cause stroke (3.3% vs. 2.8%, p = 0.31), systemic embolism (0.2% vs. 0.1%, p = 0.68), or major bleeding (6.6% vs. 6.8%, p = 0.85). Non-procedural bleeding was significantly lower with LAAO (9.2% vs. 16.7%; RR 0.55; 95% CI 0.47-0.64; p < 0.0001), though there was a numerical trend toward more ischemic stroke events (2.7% vs. 2.0%; RR 1.35; 95% CI 0.97-1.88; p = 0.08). CONCLUSION:LAAO offers similar overall efficacy and safety to modern antithrombotics. It represents a clinical trade-off: accepting a known upfront procedural risk for a robust, long-term reduction in non-procedural bleeding, potentially at the cost of a slight numerical increase in ischemic stroke.
BACKGROUND:Catheter ablation is an established rhythm control strategy for atrial fibrillation (AF) but carries a small risk of serious complications that may require emergent surgical intervention. Historically, the availability of on-site cardiothoracic surgery (CTS) has been considered an important safety requirement. However, contemporary advances in ablation techniques and peri-procedural care have improved procedural safety, and real-world data evaluating the impact of on-site CTS availability in current practice remain limited. METHODS:We analyzed the National Readmissions Database (NRD) from 2016 to 2021 to identify adults undergoing catheter ablation for AF. Hospitals were classified based on the presence of on-site CTS, defined by the performance of coronary artery bypass graft surgery. Baseline characteristics were compared between groups. Multivariable logistic regression was used to assess the association between on-site CTS availability and in-hospital complications, mortality, discharge disposition, and 30-day all-cause readmissions, adjusting for demographic and clinical covariates. RESULTS:Among 81 471 patients undergoing AF ablation, 3.3% were treated at centers without on-site CTS and 96.7% at centers with CTS. Patients treated at centers without CTS were older, more frequently female, and had a higher comorbidity burden, including greater thromboembolic risk. After multivariable adjustment, on-site CTS availability was not independently associated with in-hospital mortality, cardiac perforation, pericardiocentesis, need for open heart surgery, vascular, pulmonary, or neurological complications, discharge to home, or 30-day readmissions. CONCLUSION:In this large, contemporary national cohort, the availability of on-site cardiothoracic surgery was not independently associated with improved peri-procedural or short-term outcomes following AF ablation.
OBJECTIVE:This study aimed to compare the incidence of post‑procedural complications in patients undergoing radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) performed during daytime versus nighttime hours. METHODS:This retrospective study included 2951 patients who underwent AF ablation at three centers between 2019 and 2024. Based on procedure start time, patients were assigned to a daytime group (08:00-16:00, n = 1503) or a nighttime group (16:00-24:00, n = 1301). Propensity score matching (PSM) was used to balance baseline characteristics. The primary outcome was any complication within 3 months post‑ablation. Secondary outcomes included in‑hospital and post‑discharge complications (within 3 months) and freedom from atrial arrhythmia recurrence at 12 months. RESULTS:Following 1:1 PSM, 1263 matched pairs were analyzed. The overall postoperative complication rate was significantly higher in the nighttime group than in the daytime group (4.99% vs. 2.30%; odds ratio [OR]: 2.23; 95% confidence interval [CI]: 1.43-3.49; p < 0.001). This elevated risk was consistent for both in-hospital complications (OR: 2.14; 95% CI: 1.23-3.72; p = 0.007) and post-discharge complications (OR: 2.32; 95% CI: 1.10-4.90; p = 0.027). Furthermore, there was no significant difference in the 12-month freedom from atrial arrhythmia recurrence between the two cohorts. CONCLUSIONS:Nighttime AF ablation is associated with a significantly increased risk of overall postoperative complications, highlighting procedural timing as a critical determinant of perioperative patient safety.
INTRODUCTION:In patients with ischemic cardiomyopathy (ICM), recurrent VF may be treated with catheter ablation by targeting triggering premature ventricular complexes (PVCs) and/or ventricular scar homogenization. Data on optimal ablation strategies in patients with non-ischemic cardiomyopathy (NICM) remain limited. This study aimed to compare ablation strategies and outcomes in patients with recurrent VF due to ICM versus NICM. METHODS AND RESULTS:We retrospectively analyzed consecutive patients with structural heart disease and recurrent VF undergoing catheter ablation. Catheter ablation was performed, including targeting the triggering and/or clinically frequent PVC, targeting any inducible ventricular tachycardia, and/or scar homogenization. Procedural characteristics, arrhythmogenic substrate features, and post-ablation clinical outcomes were compared between ICM and NICM groups. Forty-five patients were included (17 ICM, 28 NICM; mean age 60 ± 15 years; 87% male). PVC ablation was performed in 42% of ICM and 39% of NICM patients, while scar homogenization was undertaken in 76% and 57%, respectively. Left ventricular scar burden, assessed by bipolar and unipolar voltage mapping, was significantly greater in the ICM, whereas the prevalence of abnormal Purkinje potentials was similar between groups. VF-free survival after multiple procedures did not differ between groups, with estimated 1-year rates of 87 ± 9% in ICM and 85 ± 8% in NICM (log-rank p = 0.93). CONCLUSIONS:In patients with NICM and recurrent VF, catheter ablation targeting arrhythmogenic substrate-including unipolar low-voltage regions-combined with PVC ablation yields outcomes comparable to those in ICM, supporting this approach as a reasonable treatment strategy.
INTRODUCTION:Diagnosis and treatment of children and adolescents with suspected Brugada syndrome (BrS) is challenging. Aim of the study was to evaluate the applicability of current diagnostic criteria for pediatric patients with suspected BrS in the German multicenter study COGIA and to assess clinical outcome. METHODS:Data analysis of 76 pediatric patients from 12 German tertiary care centers. Primary outcome was defined by the occurrence of a major arrhythmic event (MAE), secondary outcome by symptoms, pharmacotherapy and implantation of devices. MAE was defined as sudden cardiac death (SCD), aborted cardiac arrest (ACA) and appropriate implantable cardioverter-defibrillator (ICD) therapy. RESULTS:Criteria for BrS diagnosis were fulfilled in 39/76 pediatric patients (51.3%) according to ESC Guidelines, including 34 patients (44.7%) according to Shanghai Score. Genetic testing identified a (likely) pathogenic SCN5A variant in 31/66 tested children (47.0%) (14/30 with clinical diagnosis (46.7%) and 17/36 without clinical diagnosis (47.2%)). Twenty-four patients (31.6%) showed a spontaneous type 1 ECG pattern, in 6 patients (7.9%) it was induced by fever. Ajmaline challenge was positive in 19/25 patients (76.0%). Syncope occurred in 15 patients (19.7%) and an ICD was implanted in 7 pediatric patients (9.2%). Four patients (5.3%) experienced a MAE (ACA), all of them fulfilling diagnostic criteria. "Symptoms at first consultation" was identified as an independent risk factor for MAE in the whole cohort (HR = 11.3, p = 0.04). CONCLUSION:Establishing the diagnosis of BrS remains challenging in the pediatric cohort. MAE occurred in 5.3% of patients with suspected BrS. Symptoms at first consultation increased risk for MAE. CLINICAL TRIAL REGISTRATION:The study is registered at the German Clinical Trial Register (DRKS) of the Federal Institute for Drugs and Medical Devices (BfArM), DRKS-ID DRKS00028138.
BACKGROUND:Pulmonary vein isolation (PVI) using pulsed field ablation (PFA) for atrial fibrillation (AF) is becoming increasingly widespread. However, characteristics of atrial tachycardia (AT) recurrence after PFA remain unclear. We aimed to investigate characteristics of AT recurrence in comparison with AF recurrence after PFA-based PVI. METHODS:We analyzed 60 consecutive patients who underwent repeat ablation for recurrent atrial tachyarrhythmia after initial PVI alone performed with a pentaspline PFA system. Patients were classified into an AT group (at least one AT episode before repeat ablation) and an AF group (AF recurrence only). Baseline characteristics, pulmonary vein (PV) reconnections, and recurrence-free rate after repeat ablation procedure were assessed. RESULTS:The AT group consisted of 34 patients (57%). In the multivariate analysis, absence of PV reconnections was independently associated with AT recurrence (p = 0.037). All mappable ATs were macro-reentrant circuits and none were directly related to PVs. Recurrence-free rate after repeat ablation did not differ between AT and AF groups (p = 0.277). However, patients presenting in AT at the beginning of the repeat procedure had the most favorable outcomes, whereas those in AF had the poorest (p = 0.042). CONCLUSIONS:After PFA-based PVI, AT recurrence was characterized by lower PV reconnection rates and macro-reentrant circuits remote from the PVs, whereas AF recurrence was more frequently associated with PV reconnections. While overall outcomes after repeat ablation were comparable, baseline rhythm at the repeat procedure was associated with prognosis, underscoring the importance of tailored mapping and ablation strategies after PFA.
INTRODUCTION:The safety and efficacy of the atrial leadless pacemaker (A-LP) with helix fixation have been demonstrated. Usually, elevated acute thresholds decrease gradually and normalize within 24 h. Here, we report a case of subacute re-elevation of pacing thresholds after hospital discharge. CASE PRESENTATION:An 80-year-old female with a history of bradycardia underwent A-LP implantation. At the time of the procedure, the final pacing threshold (PT) was measured at 4.0 V/0.4 ms. On post-procedural Day 1, the PT at 0.4 ms pulse width decreased to 1.0 V. On Day 4, the PT was 1.0 V/0.4 ms prior to the patient's discharge. However, on Day 5, she was readmitted to the hospital due to the loss of atrial capture at the maximum output available after an intravenous administration of 150 mg amiodarone for atrial flutter. Over 3 days of monitoring, atrial PT was higher than 6 V/1.5 ms. A traditional DDD pacemaker was implanted due to recurrent sinus asystole associated with dizziness. At the 1-month follow-up, the PT of atrial A-LP was 0.5 V/0.4 ms. Two months later, an ambulatory Holter confirmed the stable and normal atrial capture of the A-LP after lowering the base rate of the DDD pacemaker. At the 3-month follow-up, PT of the A-LP remained 0.5 V/0.4 ms. CONCLUSION:Sub-acute re-elevated PT of the A-LP during the perioperative period may persist for more than 1 week and then normalize within 1 month. If PT re-elevation is suspected to be related to peri-electrode inflammation, a conservative approach with continued monitoring of threshold changes may be considered.
INTRODUCTION:Leadless pacemakers (LPs) offer advantages over transvenous systems, but atrial LPs currently target the right atrial appendage (RAA), risking atrial dyssynchrony. METHODS AND RESULTS:We report five patients in whom electroanatomic mapping and intracardiac ultrasound guided LP implantation into Bachmann's bundle (BB), a site shown to improve interatrial conduction and reduce atrial fibrillation risk. In four of five patients, BB fixation was successful with low pacing thresholds and short P-wave duration. One patient required conversion to RAA pacing due to high BB pacing thresholds. No intraprocedural complications occurred. CONCLUSIONS:This series demonstrates the feasibility of leadless BB pacing, though technical challenges warrant further study.
We aim to compare the impact of left atrial appendage closure vs. medical therapy on clinical outcomes in patients with atrial fibrillation, focusing on key clinical outcomes relevant to thromboembolic prevention. We conducted a PRISMA-guided systematic review and meta-analysis of studies comparing LAAC with medical therapy in AF adults. PubMed, Embase, Scopus, ClinicalTrial. gov, and Cochrane Library were searched from inception to March 2026. Outcomes included all-cause mortality, any stroke, ischemic stroke, hemorrhagic stroke, major bleeding, systemic embolism and cardiac death. Risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using random-effects models. Reconstructed individual patient-level survival data from published Kaplan-Meier curves were used for time-to-event analyses. Trial sequential analysis (TSA) assessed the conclusiveness of cumulative evidence. Six randomized controlled trials involving 7004 patients were included. LAAC demonstrated comparable outcomes to medical therapy for all-cause mortality, any stroke, major bleeding, systemic embolism, and cardiac death. There was a non-significant trend toward increased ischemic stroke and reduced hemorrhagic stroke with LAAC. Reconstructed time-to-event analyses showed similar cumulative incidence of stroke and bleeding outcomes over follow-up. TSA demonstrated that the required information size was not reached for any major endpoint, indicating that current evidence remains underpowered and additional randomized trials are needed. LAAC provides similar overall efficacy and safety compared with medical therapy for stroke prevention in AF but should currently remain reserved for selected patients rather than replacing oral anticoagulation broadly. Further adequately powered trials with longer follow-up are required.
BACKGROUND:Atrial tachyarrhythmias frequently recur after surgical ablation and often require catheter ablation (CA). METHODS:We conducted a retrospective cohort study of patients who underwent CA for symptomatic atrial fibrillation or flutter (AF hereafter) following surgical ablation. Clinical data, including patient and surgical characteristics and results of electrophysiology testing and mapping, were recorded. Recurrence was defined as 30 s of AF, atrial flutter, or atrial tachycardia following a 3-month blanking period. RESULTS:Thirty-seven patients were included in the study (mean age 67.0 ± 9.8 years, 43% female) who underwent isolated surgical ablation (n = 5), concomitant mitral valve surgery (n = 21), aortic valve (n = 5), tricuspid valve surgery (n = 6), and/or coronary artery bypass grafting (n = 6). The mean time from surgical ablation to CA was 5.9 ± 5.1 years. Among the 37 patients, 19 (51%) experienced one or more pulmonary vein reconnections (mean 3.0 ± 1.3 veins per patient), and 15 (41%) developed mitral annular flutter. Following ablation, 12 (32%) patients developed recurrent arrhythmia by 1-year post-ablation. Age, sex, body mass index, time from surgical ablation to CA left ventricular ejection fraction < 50%, prior CA, left atrial diameter, and mitral annular flutter were not associated with recurrence. The number of pulmonary vein reconnections at the time of repeat CA was predictive of arrhythmia recurrence in subsequent follow-up (OR 2.148 [95% CI: 1.059-4.357]; p = 0.034). CONCLUSIONS:Pulmonary vein reconnection and mitral annular flutter are common recurrence mechanisms in patients with symptomatic arrhythmia recurrence following surgical ablation. The number of pulmonary vein reconnections predicts recurrent arrhythmia.
BACKGROUND:Low-voltage areas (LVA) in the left atrium (LA) have been linked to atrial fibrillation (AF) recurrence. However, prior studies lacked high-density mapping catheter (HMDC) mapping, included non-pulmonary vein isolation (PVI) ablation strategies, and did not follow temporal progression of LVA in individuals. METHODS AND RESULTS:We retrospectively analyzed 1661 AF patients who had undergone initial ablation using PVI alone, and in whom voltage maps of the LA had been created with HDMCs. We investigated the relationship between LVA size (Small-LVA group: LVA < 5 cm2 and Extensive-LVA group: LVA ≥ 5 cm2) and AF recurrence. HDMCs were again used to map the LA at the time of the re-do ablation. A total of 711 patients met our inclusion criteria (Small-LVA 554, Extensive-LVA 157). During the mean follow-up period of 643.6 ± 490.5 days, 21% of Small-LVA patients (n = 117) and 33% of Extensive-LVA patients (n = 52) experienced recurrence (p < 0.005), of whom 106 (63%) underwent redo ablation. Belonging to the Extensive-LVA group was predictive of AF recurrence both after the initial ablation and after the redo ablation. They also exhibited greater non-PV related recurrence. Time-dependent progression of LVA was observed in 32 patients with a mean increase of 4.7 ± 5.1 cm2 and was significantly more frequent in the Extensive-LVA group. This progression was not linked to AF recurrence. CONCLUSION:We used high-density mapping to evaluate left atrial LVA in patients who had only received PVI, and demonstrated LVA influence on AF recurrence and recurrence patterns.
Proposed emergency department approach to syncope. After confirming true syncope and excluding immediately apparent diagnoses, assessment focuses on identifying patients at high risk of clinically significant bradyarrhythmia or other specific cardiac conditions requiring hospital admission, while avoiding unnecessary admission for isolated non-specific ECG abnormalities. The proposed recommendations and algorithm reflect the authors' interpretation of the available evidence and are intended to complement current ESC recommendations. Although informed by observational studies, they remain exploratory and have not yet been prospectively validated.
INTRODUCTION:Left atrial posterior wall (LAPW) isolation is frequently limited by residual conduction (RC) despite apparently complete endocardial linear lesions. Such conduction may involve interbundle connections between the septo-atrial and septo-pulmonary bundles or deeper conduction pathways. However, the spatial distribution and electrophysiological characteristics of these functionally defined RCs remain incompletely understood in clinical settings. METHODS:Twenty-two patients undergoing LAPW isolation were prospectively studied. Among 22 patients, 11 required additional ablation after a confirmed roof and bottom line block, in whom residual electrograms were mapped using peak frequency (PF) analysis with the EnSite system. The LAPW was divided into nine predefined anatomical segments, and segments requiring ablation to achieve complete isolation were defined as RC-positive. RESULTS:RC-positive segments predominantly clustered in the mid-central region (82%), whereas other regions were less frequently involved. PF was significantly higher in RC-positive than in RC-negative segments (460 [380-520] vs. 300 [250-400] Hz; p < 0.001), and a PF cutoff of 365 Hz demonstrated moderate discriminatory performance (area under the curve, 0.796). RC-positive segments exhibited greater electrogram fractionation during both atrial fibrillation and atrial pacing, consistent with increased local conduction complexity. Targeted ablation at these sites resulted in complete LAPW isolation in all cases without complications. CONCLUSION:Functionally defined RC within the LAPW exhibits a nonuniform spatial distribution with mid-central clustering and distinct electrophysiological characteristics. PF-based mapping may facilitate targeted identification of these regions and provide functional insights into potential non-endocardial conduction pathways in incomplete LAPW isolation.
BACKGROUND:Electrographic flow (EGF) mapping is an FDA 510(k)-cleared method for visualizing atrial activation wavefronts in atrial fibrillation (AF). Its clinical efficacy in detecting AF sources was demonstrated in the FLOW-AF randomized controlled trial, and the underlying machine learning strategy used to develop and refine EGF source detection has been recently detailed. However, EGF mapping metrics can also characterize other properties of atrial wavefront propagation-most notably Electrographic Flow Consistency (EGFC) as a measure of the health of the atrial substrate. Patients with low EGFC have been found to have recurrent AF more frequently than those with high EGFC. EGFC may therefore be additive to source presence to phenotype AF patients based on mechanism of disease and recurrence likelihood. OBJECTIVES:Present the EGFC-based Kaplan-Meier curves for each study arm of FLOW-AF and explore the clinical relevance of EGFC using prospective studies. METHODS:Unipolar electrograms were recorded using 64-electrode basket catheters in AF patients across three clinical trials. The EGF algorithm then processed these recordings to reconstruct wavefront propagation patterns. EGFC was quantified from the vector length at each point in space and averaged across spatial coordinates and mapping positions to determine the mean EGFC for each patient. As applicable, EGFC and related EGF map characteristics were compared with 12-month freedom from AF, patient demographic factors, and bipolar voltage mapping data. RESULTS:Primarily, mean biatrial EGFC < 0.62 was found to be the best metric at predicting recurrent AF in No Source and Treatment patients in FLOW-AF: it had 86% ± 11% accuracy after fivefold cross-validation. Among these patients, those with EGFC ≥ 0.62 had 6% recurrence vs. 51% recurrence in those with EGFC < 0.62; p < 0.001. Control patients with sources post-procedure had 77% vs. 100% recurrence in respective EGFC groups; p = 0.032. Follow-up analyses showed that EGFC dropped from 0.58 ± 0.15 to 0.51 ± 0.14 (paired p = 0.041) in a subgroup of patients who underwent repeat mapping 103 ± 22 days later, but it was not affected by pulmonary vein isolation (PVI) or source ablation (paired p > 0.30). It was also higher among de novo and paroxysmal AF patients than redo (p = 0.043) and non-paroxysmal AF patients (p = 0.022), respectively. Among the group of patients with low EGFC and no sources post-procedure, recurrent patients had increased EGFC spatial variability (p = 0.026) and more near-threshold sources with source activity ≥ 25% but < 26.5% (p = 0.038). Lastly, EGFC was globally and locally correlated to bipolar voltage across multiple rhythms, atria, mapping software and analysis techniques (p = 0.009). CONCLUSIONS:EGFC may provide insights on the substrate health of the patient and is predictive of recurrence likelihood. An understanding of EGFC may therefore increase mechanistic understanding of the progression and therapeutic strategies for AF ablation that can be tailored to the individual patient. CLINICAL TRIAL REGISTRATION:FLOW-AF: NCT04473963; FLOW EVAL-AF: NCT06260670; AF-FLOW Global Registry: NCT05481359.
INTRODUCTION:Patients with repaired tetralogy of Fallot (rTOF) remain at risk of ventricular tachycardia (VT). This risk is most commonly related to slow conduction within the septal isthmus, which is defined as the region between the ventricular septal defect (VSD) patch and adjacent valvular annuli. While assessment of septal isthmus conduction currently requires invasive electrophysiological mapping, the 12-lead electrocardiogram (ECG) may offer a noninvasive alternative. Therefore, the present study aimed to identify ECG markers reflecting septal isthmus conduction properties and evaluate their ability to predict isthmus conduction characteristics and VT inducibility. METHODS AND RESULTS:In five patients with rTOF undergoing septal isthmus ablation, 12-lead ECGs obtained before and after ablation were compared to identify candidate ECG markers. The identified marker was validated in an independent cohort of 23 patients stratified according to septal isthmus conduction properties into normal conduction (Normal, n = 5), slow-conducting isthmus (SCI, n = 10), and conduction block (Block, n = 8) groups. The results indicated that the terminal S wave (TSW) in lead V3 became more prominent after ablation compared with that before ablation. In the validation cohort, V3 TSW was categorized as absent, small (< 0.1 mV), or large (≥ 0.1 mV), and the TSW patterns differed significantly among the groups (p < 0.001). Specifically, absent TSW was dominant in the Normal group (4/5, 80%), small TSW was the most frequent in the SCI group (7/10, 70%), and large TSW was predominant in the Block group (7/8, 87.5%). Small TSW predicted SCI with 70% sensitivity and 85% specificity (p = 0.013), whereas large TSW predicted Block with 88% sensitivity and 80% specificity (p = 0.006). Moreover, large TSW predicted VT non-inducibility with high specificity and high positive predictive value (p = 0.019). CONCLUSION:This study indicates that V3 TSW is a simple, noninvasive ECG marker reflecting septal isthmus conduction properties in rTOF, suggesting its potential utility for VT risk stratification.
BACKGROUND:Pulmonary vein isolation (PVI) remains a cornerstone treatment for atrial fibrillation; however, residual conduction gaps often hinder first-pass success and contribute to late reconnection, leading to arrhythmia recurrence. The QDOT MICRO catheter (Biosense Webster Inc., CA, USA) is equipped with three microelectrodes at its tip. Their small size and short inter-electrode spacing allow for a more detailed recording of intracardiac potentials. This study evaluated the utility of the QDOT MICRO catheter in detecting conduction gaps during PVI. METHODS:Forty-four gaps in 40 patients undergoing initial PVI were analyzed by comparing electrograms recorded using microelectrodes and conventional 3.5-mm tip electrodes. RESULTS:At the gap sites, the local electrogram voltage recorded by microelectrodes was significantly higher than that by 3.5-mm tip electrodes (median, 0.449 vs. 0.195 mV, p < 0.001), representing a 2.3-fold amplification. The prevalence of fragmented potentials at the gap sites was significantly higher with microelectrodes than with 3.5-mm tip electrodes (61% vs. 30%, p < 0.001). In 36% of gaps, fragmented potentials were detected with microelectrodes, whereas the 3.5-mm electrodes recorded nonfragmented signals, contributing to accurate gap detection. In 11% of gaps, the amplitude was extremely low with 3.5-mm tip electrodes [median 0.107 (IQR 0.088-0.112) mV], rendering the interpretation of local electrogram challenging. However, microelectrodes amplified the signal [median 0.215 (IQR 0.176-0.283) mV], allowing for accurate identification and interpretation. CONCLUSION:Microelectrodes enhance the detection and characterization of conduction gaps, particularly under low-voltage or in scarred tissue, thereby improving ablation accuracy.
BACKGROUND:Esophageal injury is a rare but potentially fatal complication of atrial fibrillation ablation, predominantly associated with thermal energy sources. CASE SUMMARY:A 37-year-old man developed an esophago-mediastinal fistula after radiofrequency ablation for atrial fibrillation. An esophageal ulcer detected on routine post-ablation endoscopy progressed despite conservative management. Endoscopic vacuum therapy was instituted for 5 days, followed by endoscopic clip closure, resulting in complete healing without surgical intervention. CONCLUSION:This case underscores the value of post-ablation esophageal surveillance and demonstrates endoscopic vacuum therapy as an effective, minimally invasive option for managing esophageal perforation after radiofrequency ablation.
