Faculty Bibliography

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.

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.

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: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: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/UNASSIGNED:Favorable clinical outcomes are difficult to achieve in long-standing persistent atrial fibrillation (LSPAF) with catheter ablation (CA). The CONVERGE (Convergence of Epicardial and Endocardial Ablation for the Treatment of Symptomatic Persistent Atrial FIbrillation) trial evaluated the effectiveness of hybrid convergent (HC) ablation vs endocardial CA. OBJECTIVE/UNASSIGNED:The study sought to evaluate the safety and effectiveness of HC vs CA in the LSPAF subgroup from the CONVERGE trial. METHODS/UNASSIGNED:The CONVERGE trial was a prospective, multicenter, randomized trial that enrolled 153 patients at 27 sites. A post hoc analysis was performed on LSPAF patients. The primary effectiveness was freedom from atrial arrhythmias off new or increased dose of previously failed or intolerant antiarrhythmic drugs (AADs) through 12 months. The primary safety endpoint was major adverse event incidence through 30 days with HC. Key secondary effectiveness measures included (1) percent of patients achieving ≥90% AF burden reduction vs baseline and (2) AF freedom. RESULTS/UNASSIGNED:.038). Three (7.9%) major adverse events occurred within 30 days of HC. CONCLUSION/UNASSIGNED:Post hoc analysis demonstrated effectiveness and acceptable safety of HC compared with CA in LSPAF.

BACKGROUND/UNASSIGNED:Pulmonary vein isolation (PVI) ablation is a standard therapy for paroxysmal atrial fibrillation (PAF). Lesion Index (LSI) is a metric to guide radiofrequency (RF) ablation using the TactiCath Ablation Catheter, Sensor Enabled with the EnSite Cardiac Mapping System (Abbott). OBJECTIVE/UNASSIGNED:This study (NCT-03906461) was designed to capture best practices using LSI-guided catheter ablation to treat PAF subjects in a real-world setting. METHODS/UNASSIGNED:This prospective single-arm observational study enrolled 143 PAF subjects in the United States, Europe, and Japan undergoing de novo PVI with RF ablation. PVI lesions were assigned to 10 anatomically defined segments. Mean LSIs achieved for all lesions were analyzed. Follow-up was conducted between 3-6 months and 12 months after the procedure. RESULTS/UNASSIGNED:Pulmonary veins were isolated in all subjects. The mean achieved LSI was 4.9, with lower values in Europe (4.4) and Japan (4.5) than the United States (5.5). First-pass success, defined as no gaps requiring touch-up ablation after 20 minutes post isolation, was achieved in 76.2% of subjects. Use of high LSI (≥5) resulted in shorter procedure, RF, and fluoroscopy times and fewer touch-up ablations compared to low LSI (<5). At 12 months, 99.3% of subjects were free from procedure- or device-related serious adverse events and 95.7% (112/117) (35.0% on antiarrhythmic drugs) were free from recurrence and/or a repeat ablation procedure for atrial fibrillation / atrial flutter / atrial tachycardia. CONCLUSION/UNASSIGNED:LSI-guided ablation strategies proved safe and effective despite differences in LSI workflows. Use of high LSI values resulted in shorter procedure, RF, and fluoroscopy times and fewer touch-up ablations compared to low LSI.