Faculty Bibliography

Randomized trials of ethanol infusion into the vein of Marshall (EIVOM) have shown efficacy in preventing atrial fibrillation (AF) recurrence in patients presenting for de novo ablation. The utility of EIVOM in AF patients who present for redo ablation is unclear. This meta-analysis was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Medline, Scopus, and Cochrane Central Register of Controlled Trials were systematically searched to identify relevant studies. Risk of bias was assessed using the Modified Newcastle-Ottawa scale. Eligible studies reported outcomes in AF patients with previous ablation who underwent redo catheter ablation (CA) alone vs. combined redo CA and EIVOM. Five observational studies comprising 568 patients were included. When comparing combined redo CA and EIVOM vs. redo CA alone, pooled results showed no difference in freedom from arrhythmia (FFA) in all patients (risk ratio [RR] 1.13; 95% confidence interval [CI] 0.96-1.33), FFA in persistent AF patients only (RR 1.08; 95% CI 0.90-1.29), total procedure time (mean difference -0.59; 95% CI -41.04-39.85), or major periprocedural complications (RR 0.81; 95% CI 0.06-11.64). Patients with AF recurrence after ablation represent a difficult-to-treat population. Salvage therapy with combined CA and EIVOM did not improve arrhythmic outcomes compared to CA alone in AF patients who presented for redo ablation.

UNLABELLED:Oral anticoagulation (OAC) remains the primary means of stroke prevention in patients with atrial fibrillation (AF). However, there are patients at greater risk of bleeding or who have experienced major bleeding, whereby long term OAC is relatively contraindicated. Additionally, up to 55% of eligible AF patients do not utilize OAC. Thus, transcatheter left atrial appendage occlusion devices (LAAOD) present an attractive alternative to mitigate stroke risk. Randomized trials have demonstrated the noninferiority of LAAOD to OAC in reducing stroke risk. However, treatment with LAAODs presents its own risks, including the risk of device-related thrombus (DRT). In this report, we describe an unusual case of a patient with a small DRT initially identified on transesophageal echocardiography (TEE) 6 weeks after implantation of a Watchman FLX (Boston Scientific, Marlborough, MA, USA) LAAOD that was appropriately treated and resolved on TEE 6 months after implantation. However, a massive late DRT recurred 2 years after implantation. This case highlights the importance of continued device monitoring for unfavorable evolution of DRT beyond the currently recommended 45-day to 1-year monitoring period, and especially after suspected thrombus resolution. Furthermore, it underlines the importance of developing newer generation LAAOD that reduces DRT risk. LEARNING OBJECTIVE/UNASSIGNED:Left atrial appendage occlusion devices can mitigate stroke risk in atrial fibrillation patients with contraindications to oral anticoagulation. However, these devices present with their own risks, including the risk of device-related thrombus (DRT). This case highlights the importance of continued device monitoring for unfavorable evolution of DRT beyond the recommended 45-day to 1-year monitoring period.

INTRODUCTION/BACKGROUND:Sphere-9 is a lattice tip ablation catheter (Medtronic, USA) capable of delivering both pulsed field and radiofrequency ablation. It is approved for the treatment of atrial fibrillation. Adverse events related to this device have been reported to national databases. A systematic assessment of these reports is needed to understand the nature of device-related complications. METHODS:We queried the FDA Manufacturer and User Facility Device Experience (MAUDE) database between October 24, 2024 and October 24, 2025 to identify reports related to the Sphere-9 catheter. A total of 222 reports were included in the final analysis. RESULTS:Of 222 reports, 148 (67%) resulted in clinical events. Of these, 107 were suspected to be related to the Sphere-9, including: VT/VF during/following energy delivery (n = 30), Stroke/TIA (n = 25), sinus node dysfunction/AV block (n = 23), pericardial effusion (n = 7), coronary spasm (n = 9), and phrenic nerve injury (n = 2). Catheter/defibrillator (ICD) related interactions were suspected in 10 of the VT/VF reports. There were 65 catheter related reports that did not appear to be associated with adverse clinical events, which included tissue/char formation on the catheter tip (n = 24), steam pop (n = 25), and mechanical entrapment (n = 7). CONCLUSION/CONCLUSIONS:This early analysis of adverse events reported for the Sphere-9 catheter highlights complications including arrhythmias, such as VT/VF and AV block, and the risks associated with ICD-catheter related interactions.

BACKGROUND:Pulmonary vein isolation (PVI) and posterior wall isolation (PWI) are frequently used in the treatment of persistent atrial fibrillation (AF). Minimal data support adjunct PWI, possibly due to lack of durability via epicardial reconnections. OBJECTIVE:To determine the impact of very high output PW pace-capture testing in patients with persistent AF on AF/AT recurrence. METHODS:We performed a retrospective study of consecutive patients who underwent radiofrequency ablation for persistent AF and received PVI and PWI, as well as a cavotricuspid isthmus line (CTI). After the creation of three linear PW lesions (roof, carina-to-carina, and inferior PV levels), pace-capture testing was performed on the PW. The first cohort confirmed PWI using 10 mA at 2 ms (10 × 2) to pace capture. Sequentially, the second cohort utilized 20 mA at 10 ms (20 × 10). If the PW was captured, additional lesions were performed. Patients were excluded if additional lesion sets beyond PVI, PWI, and CTI were performed. RESULTS:A total of 232 patients were included. Of these, 129 (56%) patients were in the 20 × 10 group, and 103 (44%) patients were in the 10 × 2 group. The two groups did not differ in age, sex, proportion of comorbidities, presenting rhythm, left ventricular ejection fraction, or left atrial size. Despite the increase in procedure time and lesion number, in the time-to-event analysis, patients in the 20 × 10 group experienced recurrent AF/AT more frequently than those in the 10 × 2 group (log rank p = 0.01). CONCLUSION/CONCLUSIONS:Testing PWI in persistent AF with pace capture at 20 mA at 10 ms did not improve freedom from arrhythmia and may paradoxically be associated with harm. Our findings question whether PWI, regardless of durability, is effective in treating persistent AF.

INTRODUCTION/BACKGROUND:A lower frequency early electrogram (EGM) or broad area of early activation during premature ventricular contraction (PVC) mapping may be associated with a PVC origin in an opposing chamber or deep within the mapped surface. The utility of quantifying EGM frequency at early activation sites and isochronal activated surface area (IASA) is unclear. Our study aimed to investigate the utility of EGM frequency analysis and IASA mapping to complement activation mapping during PVC ablation. METHODS:High density PVC activation and IASA maps were created using a multi-electrode mapping catheter in 25 patients undergoing PVC ablation. EGMs in early activation regions were retrospectively studied. IASAs in each mapped chamber were analyzed. RESULTS:within 10 ms was unsuccessful. CONCLUSION/CONCLUSIONS:Higher EGM frequency and smaller IASA were associated with successful ablation of PVCs. Ablation at sites with EGM frequency > 325 Hz was successful in all patients. The utility of identifying higher frequency EGMs at early activation sites requires further study.

BACKGROUND:Identifying nearfield and farfield signals is critical to mapping and ablating cardiac arrhythmias. This assessment is qualitative, depending on the "sharpness" of pulmonary vein (PV) electrograms. Electrogram peak frequency (PF) analysis is hypothesized to be a quantitative measure of signal proximity. OBJECTIVE:To confirm if PF defines nearfield versus farfield electrical signals and if it can be used during ablation to establish pulmonary vein isolation (PVI). METHODS:We created a cohort of 30 patients with AF undergoing PVI. Left atrial and PV maps of PF were generated before and after PVI. In the first 10 patients with paroxysmal AF (cohort 1), a cutoff value was selected to predict nearfield versus farfield signals. This cutoff was validated in a cohort of 10 patients with paroxysmal AF (cohort 2) and a cohort of 10 patients with persistent AF (cohort 3). RESULTS:PF was lower in farfield electrograms than nearfield electrograms. A PF cutoff of 300 Hz had a sensitivity of 93.2% (95% CI 81.3% - 98.6%) in cohort 1, 90.0% (95% CI 76.3 - 97.2) in cohort 2, and 98.6% (95% CI 90.1 - 99.7%) in cohort 3 for differentiating farfield from nearfield electrograms. The specificity was 100.0% (95% CI 98.2% - 100.0%) and the AUC was 0.99 (95% CI 0.97 - 1.00) in all patients. CONCLUSIONS:We confirmed the hypothesis that PF distinguishes nearfield from farfield electrograms. PF analysis improves the recognition of PV isolation. Mapping and ablation strategies utilizing PF should be pursued to improve ablation outcomes.

BACKGROUND:Vein of Marshall (VOM) ethanol ablation is effective in preventing recurrence in patients with persistent atrial fibrillation (AF) as a de novo strategy. There is minimal data on its use in recurrent AF. OBJECTIVE:We investigated the efficacy of VOM ethanol ablation for recurrence despite initial AF ablation. METHODS:Retrospective analysis was performed of persistent AF patients who underwent repeat ablation after an initial ablation for persistent AF. All patients had pulmonary vein isolation (PVI), posterior wall isolation (PWI), and cavotricuspid isthmus (CTI) during their previous ablation(s). At redo ablation, controls underwent confirmation and completion of previous ablation steps, substrate modification, and a search for non-PV triggers. Cases had additional VOM ethanol ablation combined with mitral isthmus ablation. RESULTS:One hundred and seven patients (49 VOM, 60 control) were included. There was no difference in AF recurrence at 1-year comparing VOM patients (47%) and controls (38%), (p = 0.39). Within the VOM group, the mean AF burden decreased from 38% preablation to 10% 12-months post (p = 0.003). The proportion of recurrent persistent AF decreased from 65% preablation to 26% post (p = 0.004). There was no significant difference in reduction in AF burden or proportion of recurrent persistent AF when comparing VOM cases and controls. Six percent of VOM patients developed intraprocedural left atrial appendage (LAA) isolation. CONCLUSIONS:In patients with previous PVI, PWI, and CTI ablation, VOM ethanol ablation did not demonstrate a reduction in AF recurrence or burden when compared with a strategy of substrate modification and trigger ablation alone and increases the risk of LAA isolation.

AIMS/UNASSIGNED:We aimed to develop and externally validate a convolutional neural network (CNN) using sinus rhythm electrocardiograms (ECGs) and CHARGE-AF features to predict incident paroxysmal atrial fibrillation (AF), benchmarking its performance against the CHARGE-AF score. METHODS AND RESULTS/UNASSIGNED:We curated 157 192 sinus ECGs from 76 986 patients within the New York University (NYU) Langone Health system, splitting data into training, validation, and test sets. Two cohorts, from suburban US outpatient practices and Greek tertiary hospitals, were used for external validation. The model utilizing the sinus ECG signal and all CHARGE-AF features achieved the highest test set area under the receiver operator curve (AUC) (0.89) and area under the precision recall curve (AUPRC) (0.69), outperforming the CHARGE-AF score alone. Model robustness was maintained in the external US cohort (AUC 0.90, AUPRC 0.67) and the European cohort (AUC 0.85, AUPRC 0.78). Subgroup analyses confirmed consistent performance across age, sex, and race strata. A CNN using ECG signals alone retained strong predictive ability, particularly when simulating missing or inaccurate clinical data. CONCLUSION/UNASSIGNED:Our CNN integrating sinus rhythm ECGs and CHARGE-AF features demonstrated superior predictive performance over traditional risk scoring alone for detecting incident paroxysmal AF. The model maintained accuracy across geographically and clinically diverse external validation cohorts, supporting its potential for broad implementation in AF screening strategies.