Faculty Bibliography

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.

BACKGROUND:Pulmonary vein (PV) isolation is the cornerstone of radiofrequency (RF) ablation for atrial fibrillation (AF) and PV reconnection is a common cause of recurrent AF. The relationship between PV ostial wall thickness (WT) and durable PV isolation is a matter of ongoing investigation. Additionally, the relationship between catheter impedance and WT is not well understood. We studied the relationship between PV ostial WT, ablation lesion metrics, and PV reconnection. METHODS:16 patients were identified who underwent an initial and redo AF ablation procedure and had a cardiac CTA analyzed using ADAS-3D imaging software performed prior to the initial ablation. Ablation lesion metrics from the initial ablation procedure were collected from the electroanatomic mapping software. Reconnected and isolated PV were identified based on electroanatomic mapping data collected at the redo AF ablation procedure. Patients with reconnected PV exhibited thicker left atrial walls (1.4 mm vs 1.2 mm, P < 0.05) and reconnected veins exhibited thicker ostial walls (1.7 mm, vs 1.5 mm, P < 0.05). LA volume, number of ablation lesions, and ablation lesion time were not significantly different between reconnected and isolated PV. Impedance drop during ablation was greater in patients with reconnected PV compared to patients with isolated PV (- 9.0 Ω vs - 6.6 Ω, P < 0.05). There was no correlation between PV ostial WT and ablation lesion impedance drop. CONCLUSION/CONCLUSIONS:PV reconnection was associated with thicker LA and PV ostial WT. Future studies will examine whether targeting thicker PV ostial tissue with more aggressive lesion metrics or different ablation technology can improve PV isolation and ablationoutcomes.

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.

OBJECTIVES/OBJECTIVE:Assess the characteristics and management of patients with LAA thrombus despite compliance with oral anticoagulation (OAC). BACKGROUND:Atrial fibrillation guidelines consider 4 weeks of uninterrupted OAC sufficient to avoid transesophageal echocardiography to rule out left atrial appendage thrombus. However, some patients may exhibit persistent thrombus despite compliance with OAC. METHODS:Clinical history, management, and outcomes were reviewed for patients with LAA thrombus on preprocedural TEE presenting for an AF related procedure between 2021 and 2024. RESULTS:Sixty-five (1.8%) of 3653 preprocedural TEEs exhibited LAA thrombus. OAC compliance of at least 4 week was documented in 39 (60%) of these patients, including Apixaban 64%, Rivaroxaban 23%, Warfarin 8%, Dabigatran 5%. Two of these patients (3%) experienced an embolic event and 8 (12%) died during the follow up period. Resolution of LAA thrombus was documented in 12/32 patients, 6 who switched to Dabigatran, 2 to Eliquis, 1 to Warfarin, and 3 remained on Eliquis. LAA-occlusion was successfully performed in seven patients with persistent LAA thrombus. CHADS-VASc 3 or greater, HFrEF, or valvular AF were present in 37/39 of these patients. CONCLUSION/CONCLUSIONS:For 3653 patients who underwent Preprocedural TEE, 39 exhibited LAA thrombus despite compliance with OAC. Switching OAC or maintaining the same agent for longer period of time resolved the thrombus in 31% of cases. LAA-O was effective in cases where the thrombus did not resolve. Patients with non-valvular AF, compliance with OAC > 4 weeks, CHADS-VASc ≤ 2, and normal EF exhibited the lowest probability for not having a thrombus on TEE.

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:Left atrial appendage occlusion (LAA-O) with Amulet and Watchman FLX are approved for reducing stroke risk in patients with atrial fibrillation when oral anticoagulation is not tolerated. Real world clinical outcomes reported along with imaging data are needed to help clinicians choose between these two technologies and manage device-related complications. METHODS:The study retrospectively analyzed clinical, transesophageal (TEE), and available computed tomography (CT) data from 364 FLX and 292 Amulet procedures performed at an academic medical center over a 4-year period. RESULTS:were included. TTE LAA-orifice area correlated with CT-derived measurements. There were more late pericardial effusions for Amulet (3.1%) compared to FLX (0.3%), though the majority were conservatively managed. Mean procedure times were similar (FLX 64 ± 24, Amulet 65 ± 21 min) as were the rates of device related thrombus (FLX 1% and Amulet 1.4%). Clinically relevant peridevice leak (PDL) on follow-up TEE imaging was greater for FLX (16%) compared to Amulet (10%). Combined AF ablation-LAA-occlusion procedures exhibited lower rates of PDL and late pericardial effusions compared to solo procedures. CONCLUSIONS:Based on retrospective analysis, an initial strategy with Watchman FLX in patients with favorable LAA anatomy would reduce the risk of late pericardial effusions at the expense of a higher rate of clinically relevant PDL compared to Amulet. Combined AF ablation and LAA-O procedures exhibit less PDL.

BACKGROUND:Recent evidence suggests atrial fibrillation (AF) causes cardiomyopathy due to remodeling driven by both irregular rate and rhythm. Atrial fibrillation (AF) ablation in patients with reduced ejection fraction (EF) ≤ 35% has been shown to improve EF and mortality. It is unknown whether the benefits of AF ablation among patients with reduced EF are affected by the degree of pre-ablation rate control. OBJECTIVES/OBJECTIVE:To evaluate AF ablation echocardiographic outcomes for patients who have EF ≤ 35% with varying degrees of pre-ablation rate control. METHODS:Single-center, retrospective study of patients with EF ≤ 35% undergoing first-time ablation of persistent AF. Primary analyses evaluated the degree to which pre-ablation rate control impacted echocardiographic outcomes. Rates of EF recovery to > 35% were compared at three different cutoffs: 110 bpm, 90 bpm, and 70 bpm. A linear regression analysis was then performed to evaluate whether baseline heart rate (HR) predicted change in EF. RESULTS: = 0.05, p = 0.07). CONCLUSIONS:Catheter ablation of persistent AF in patients with reduced EF frequently resulted in recovery in EF > 35%, irrespective of pre-ablation achieved rate control. While patients with HR > 70 bpm experienced a greater improvement in EF compared to those ≤ 70 bpm, patients with baseline HR below this target still experienced significant EF improvements. Further investigation into irregularity-mediated cardiomyopathy is warranted.

BACKGROUND:Genetic testing is a cornerstone in the assessment of many cardiac diseases. However, variants are frequently classified as variants of unknown significance, limiting the utility of testing. Recently, the DeepMind group (Google) developed AlphaMissense, a unique artificial intelligence-based model, based on language model principles, for the prediction of missense variant pathogenicity. We aimed to report on the performance of AlphaMissense, accessed by VarCardio, an open web-based variant annotation engine, in a real-world cardiovascular genetics center. METHODS AND RESULTS/RESULTS:<0.001). Genotype-phenotype concordance was highly aligned using VarCard.io predictions, at 95.9% (95% CI, 92.8-97.9) concordance rate. For 109 variants classified as pathogenic, likely pathogenic, benign, or likely benign by ClinVar, concordance with VarCard.io was high (90.5%). CONCLUSIONS:AlphaMissense, accessed via VarCard.io, may be a highly efficient tool for cardiac genetic variant interpretation. The engine's notable performance in assessing variants that are classified as variants of unknown significance in ClinVar demonstrates its potential to enhance cardiac genetic testing.

BACKGROUND:Many patients with mildly to moderately reduced left ventricular ejection fraction (LVEF) who require permanent pacemaker (PPM) implantation do not have a concurrent indication for implantable cardioverter-defibrillator (ICD) therapy. However, the risk of ventricular tachycardia/ventricular fibrillation (VT/VF) in this population is unknown. OBJECTIVE:The aim of this study was to describe the risk of VT/VF after PPM implantation in patients with mildly to moderately reduced LVEF. METHODS:Retrospective analysis was performed of 243 patients with LVEF between 35% and 49% who underwent PPM placement and did not meet indications for an ICD. The primary end point was occurrence of sustained VT/VF. Competing risks regression was performed to calculate subhazard ratios for the primary end point. RESULTS:Median follow-up was 27 months; 73% of patients were male, average age was 79 ± 10 years, average LVEF was 42% ± 4%, and 70% were New York Heart Association class II or above. Most PPMs were implanted for sick sinus syndrome (34%) or atrioventricular block (50%). Of 243 total patients, 11 (4.5%) met the primary end point of VT/VF. Multivessel coronary artery disease (CAD) was associated with significantly higher rates of VT/VF, with a subhazard ratio of 5.4 (95% CI, 1.5-20.1; P = .01). Of patients with multivessel CAD, 8 of 82 (9.8%) patients met the primary end point for an annualized risk of 4.3% per year. CONCLUSION:Patients with mildly to moderately reduced LVEF and multivessel CAD undergoing PPM implantation are at increased risk for the development of malignant ventricular arrhythmias. Patients in this population may benefit from additional risk stratification for VT/VF and consideration for upfront ICD implantation.