BACKGROUND:Integration of catheter-tissue contact force with pulsed field ablation (PFA) dosing is essential for achieving safe and durable lesion formation with contact force sensing catheters in ventricular models. However, data on the use of these catheters for atrial ablation remain limited. This study evaluated the procedural safety and 30-day lesion characteristics of atrial PFA delivered with the OMNYPULSE ablation catheter in a porcine model. METHODS:Twelve pigs were randomized to receive either 6 (×6 or Group A) or 12 (×12 or group B) PFA applications per ablation. Following 3-dimensional electroanatomic mapping, PFA was delivered to the right superior and inferior pulmonary veins, cavotricuspid isthmus, right atrial posterior wall, left atrial roof, and mitral annulus. Procedural safety was assessed acutely, and lesion characteristics were evaluated on 30-day histology. Maximum transmurality extent (MTE) was defined as >80% of the lesion span exhibiting continuous endocardial-to-epicardial fibrosis within representative histological sections. RESULTS:Adequate catheter-tissue contact was achieved during PFA delivery (contact force, 28±15 g). No acute procedural complications were observed. At 30 days, PVs and right atrial sites (ie, cavotricuspid isthmus and right atrial posterior wall) demonstrated near-complete MTE regardless of PFA dosing. In contrast, MTE was significantly lower at the mitral annulus and LA roof compared with other sites (44±30% and 21±26%, respectively; P<0.001). Increasing the number of PFA applications (×12) resulted in a remarkable improvement in MTE at these locations, with MTE increases of up to 68% compared with ×6 dosing at these sites. CONCLUSIONS:Atrial PFA using the OMNYPULSE catheter was feasible and safe in a porcine model. However, lesion transmurality varied by atrial location and was dose-dependent at select sites, underscoring the need for site-specific PFA dosing strategies. Further studies are warranted to define optimal PFA parameters for consistent atrial lesion formation.

Background: Rhythm control with catheter ablation (CA) of atrial fibrillation (AF) leads to reverse remodeling of AF substrate. Comorbidities may impact this process and outcomes. Sparse cardiovascular (CV) guidelines address comorbidities and rhythm control practices after CA. We characterized incident comorbidities after index CA that may impact outcomes, reablation, or antiarrhythmic drug (AAD) practices after CA in the ARRC-AF study. Methods: 2,429,863 patients in Optum’s deidentified Market Clarity Data (Market Clarity ® ) newly diagnosed with AF (2007–2021) were followed until disenrollment, death, or study end; 23,323 patients underwent index CA. Comorbidity status before CA and comorbidity event rates after CA were analyzed. We examined these before and during intervening periods between CAs and while receiving medical therapy. Results: Among the 23,323 patients who underwent index CA (median follow-up: 3.2 years; 44.6% prescribed AADs), baseline comorbidities included hypertension (51.8%), coronary artery disease (17.9%), obstructive sleep apnea (14.4%), diabetes (11.7%), heart failure (10.5%), chronic obstructive pulmonary disease (8.9%), peripheral vascular disease (5.4%), valvular heart disease (4.9%), and chronic kidney disease (1.1%). During follow up, 19,461 patients (83.4%) had no further CA; 3,862 patients (46.7% prescribed AADs) had ≥1 reablation (1 reablation, 14.2%; 2 reablations, 2.0%; ≥3 reablations, 0.4%; interval between Cas of 539, 536, and 458 days, respectively). Individual comorbidity event rates after CA ranged from 0 to 4.7% in the 3 cohorts with ≥1 comorbidity/patient ( Table ). Conclusion: After CA, new comorbidities continue to emerge at a modest rate. In general, comorbidity event rates increased as the number of reablations increased. Both CV and non-CV comorbidities need to be assessed before reablation (with and without long-term AAD therapy) for potential impact on endpoints and need best practice management. Co-morbidities can impact outcomes and need to be considered for their impact on sample sizes, study endpoints, morbidity, and mortality in AF ablation trials. Optimizing management of comorbidities could potentially improve results of AF interventions

Background: Patients who are older and those that are frail are routinely referred for LAAC but may be at increased risk of adverse events following device implant. It is unclear how age and frailty interact and if measures of frailty can support risk stratification in older adults. Research Question: Will measures of frailty improve risk stratification for LAAC in older adults? Methods: The WATCHMAN FLX Pro Device SURveillance Post Approval AnalySiS Plan (SURPASS Pro) is a multicenter, prospective, observational analysis that acquires data from the NCDR LAAO Registry. Patients discharged Oct 2023 – Jun 2024 with an attempted WATCHMAN FLX Pro implant were stratified by age (≥80 and <80 years) and then by frailty (non-frail, pre-frail, and frail) based on measures of hemoglobin, creatinine, albumin, BMI, and increased fall risk. Key safety events (death, ischemic stroke, systemic embolism, device/procedure-related events through discharge or 7 days, whichever is later) and clinical events through 45 days were assessed. Results: Of 21,595 patients in SURPASS Pro, 8,203 (38.0%) were ≥80 years and 13,392 (62.0%) were <80 years old. The older group had a higher mean CHA 2 DS 2 -VASc score (5.0 ± 1.4 vs 4.3 ± 1.4) and slightly fewer females (39.4% v 43.7%). Implant success was high for both groups (96.3% [≥80] and 97.3% [<80]). Composite occurrence of key safety events was similar (0.27% [≥80] and 0.16% [<80]; p=0.10), but mortality was higher in those ≥80 (0.18% v 0.05%; p<0.01). The older group had 1,394 (17%) non-frail, 6,629 (80%) pre-frail, and 180 (2.2%) frail individuals. Frailty showed a significant association for the key safety endpoint (p<0.01) driven by mortality (Table 1) and frailty was associated with increased 45-day mortality (p<0.01) (Figure 1A). The younger group had 4,104 (31%) non-frail, 9,156 (68%) pre-frail, and 132 (1%) frail individuals. In this group, frailty showed a significant association for the key safety endpoint (p<0.01) driven by ischemic stroke and device or procedure-related events (Table 1). Frailty was also associated with higher rates of 45-day mortality and bleeding in the younger group (Figure 1B). Conclusion: Only 1 in 5 patients ≥80 years undergoing LAAO is non-frail. Age ≥80 years and frailty are associated with higher relative rates of safety events and mortality, though the absolute risks are very low. Frailty and age ≥80 years can help refine clinical risk stratification for LAAC but should not be considered prohibitory.

Background: Accurate prediction of whether a ventricular tachycardia (VT) source or critical isthmus is epicardial may facilitate efficient and effective catheter ablation. Prior visual criteria have been described but performance may vary depending upon region. Hypothesis: We hypothesized that an artificial intelligence (AI) algorithm would provide more accurate identification of epicardial versus endocardial sources distributed throughout the left ventricle (LV) compared with visual analysis. Aims: We endeavored to assess the performance of a novel AI algorithm in separating epicardial and endocardial VT and pacing sources compared with 7 previously published ECG criteria. Methods: Patients with LV VT or pacing were enrolled. Episodes were grouped as either LV-endocardial or non-LV-endocardial (i.e., epicardial) according to site of successful ablation or location of the pacing electrode. 12-lead ECG data was analyzed using the AI algorithm to predict source location and accuracy was computed. For comparison, accuracy of 7 previously described visual ECG criteria was assessed. Results: A total of 136 arrhythmia or pacing episodes from 72 patients (mean age 66±14 y, 32% female, EF 39±16%) were analyzed, evenly distributed between epicardial (n=68, 50%) and endocardial (n=68) sources. Episodes were localized to all 17 AHA LV segments. Algorithm accuracy was 91.1% (124 of 136 episodes), exceeded the best performing visual ECG criteria (shortest precordial rS >121 msec; 62.5%; 85 of 136 episodes; P<0.001). Algorithm sensitivity was 0.971 [95% CI: 0.898 - 0.996] and specificity was 0.853 [95% CI: 0.746 - 0.927]. Figure A shows an example ECG from a 73-year-old patient undergoing epicardial pacing at the inferior left ventricular apex. Figures B, C, and D show orthogonal views of the local normal vector (blue) and the electrical activation vector (red), consistent with an epicardial origin. Conclusions: The AI algorithm provided improved accuracy versus visual ECG criteria. Future studies are required to assess whether such information improves procedural efficiency.

Background: Cardiac resynchronization therapy (CRT) is an important treatment modality for patients with heart failure and electrical dyssynchrony. A current limitation is that approximately 30% of patients do not respond, and identification of patients at greater risk for suboptimal outcome remains challenging. Hypothesis: We hypothesized that an artificial intelligence (AI) ECG mapping system would identify maladaptive ECG activation patterns in non-responders to CRT-defibrillator (CRT-D) therapy. Aims: We endeavored to analyze the biventricular-paced 12-lead ECG QRS complex using a novel AI tool and compare the projected segment of origin between responders and non-responders. Methods: We enrolled patients with heart failure 6 months or more after CRT-D implantation. ECG samples obtained during routine clinical follow-up during LV, RV, and BiV pacing were analyzed with an AI-based ECG mapping system. The projected segments of origin for each pacing setting were noted using a validated 30 segment ventricular model. CRT responders were defined as ≥5% increase in LVEF at 6 to 12 months post-implantation. Results: Of 49 study patients, 35 were responders (age 74±9 y, LVEF 28±9%, 31% female) and 14 were non-responders (age 68±12 y, LVEF 32±5%, 20% female). LVEF increased in responders by 15±7% and decreased in non-responders by 3±5% (p<0.001). Biventricular-paced ventricular activation patterns were significantly different between responders and non-responders: in non-responders, 8 of 14 patients (57.1%) had an activation pattern identified as mid to apical anterior or anteroseptal (Figure A) versus 6 of 35 responders (Figure B, 17.1%, p= 0.012). Left ventricular and right ventricular activation mapping results were not predictive. Conclusions: A maladaptive biventricular-paced electrical activation pattern, localized to the mid- or apical anteroseptal region of the LV, is associated with non-response to CRT. Studies of intraprocedural noninvasive LV activation mapping to improve target LV pacing site selection and response to CRT are underway.

Introduction: Patients undergoing atrial fibrillation (AF) ablation have historically been hospitalized overnight or longer post-procedure. We conducted this study to characterize national rates of same-day discharge, associated clinical factors, variation across hospitals and in-hospital outcomes. Methods: The NCDR AF Ablation Registry was used to identify all index procedures from January 1 st , 2016, to June 30 th , 2023. Patients were stratified by post-procedure disposition into 3 cohorts: (1) same-day discharge, (2) overnight hospitalization ( < 1-day) or (3) >1-day hospitalization. Rates of same-day discharge, associated clinical factors, hospital-level variation and unadjusted post-procedural complication rates were analyzed. Results: Among 139,391 patients who underwent index AF ablation across 197 hospitals in the US, 51622 (37.0%) were discharged the same-day, 78220 (56.1%) hospitalized overnight and 9549 (6.9%) hospitalized for >1-day post-procedure. Shown in Figure 1, the rate of same-day discharge increased from 0.99% (Quarter 1 of 2016) to 62.3% (Q2 2023), p<0.0001 for trend, with a sharp rise in Q1 of 2020 and corresponding decline in those hospitalized overnight (83.3% in Q1 2016 to 32.9% Q2 2023, p<0.0001 for trend). The quarter during which AF ablation procedure was conducted was associated with same-day discharge (OR 1.26, 95% CI 1.256-1.264, Figure 2). In contrast, Black race (OR 0.71, 95% CI 0.65-0.78), persistent AF classification (OR 0.85, 95% CI 0.82-0.88) and prior non-AF catheter ablation (OR 0.89, 95% CI 0.85-0.93) favored overnight hospitalization. Variation in same-day discharge across hospitals was significant (MOR 4.12, 95% CI 3.48-4.79). Aggregate major and overall in-hospital complication rates were 0.70% and 2.13%, respectively. In comparison, major and overall complication rates were 0.03% and 0.19% for same-day discharge and 0.24% and 0.98% for overnight hospitalization. Conclusion: Rates of same-day discharge following AF ablation increased over time and surpassed overnight hospitalization by Q1 2021. Those with paroxysmal AF and fewer comorbid conditions were more likely to undergo same-day discharge with substantial variation across hospitals. Peri-procedural complication rates of those undergoing same day discharge were comparable to overnight hospitalization. With substantial growth in same-day discharge and development of outpatient or ambulatory procedural centers, our findings may assist future procedural policy development.

Background: Unstable ventricular tachycardia is difficult to map and ablate, with high recurrence rates. We developed a 12-lead ECG mapping algorithm based on computational models to localize VT to help guide ablation of unstable VT. Hypothesis: We hypothesized that prospective ECG-mapping can facilitate invasive activation mapping and improve the success of unstable VT ablation. Aims: To compare the time to ICD shock + death in patients undergoing ECG-mapping guided ablation of unstable VT compared to standard ablation controls. Methods: Consecutive patients from 2 centers with unstable VT undergoing ECG-mapping guided VT ablation were prospectively enrolled. Using the ECG, computational mapping localized the VT onto a 3D model. A multielectrode catheter was placed at the predicted site and activation mapping was performed during VT reinduction. Ablation was performed per standard protocol. Time to ICD shock or death was compared using Cox regression (adjusting for age, EF and ICM) between ECG-mapping guided ablation vs standard VT ablation controls with a minimum 3 month f/u. Accuracy of ECG mapping was compared with activation mapping. Results: Out of 32 consecutive patients who underwent ECG-mapping guided VT ablation, 26 had unstable VT (age 66±10 yr, EF 34±17%). All 26 (100%) patients with unstable VT (median VT CL: 326±81ms) underwent successful activation mapping, Fig 1A. Using Cox regression adjusting for covariates, ECG-mapping guided VT ablation had a significant reduction in ICD shock or death compared to standard ablation controls (p=0.01, HR=0.23 [CI 0.07-0.70], Fig 1B). There was a 99% reduction in total ICD shocks during mean 7.5 month f/u. For all 32 patients, the mean accuracy of ECG mapping was 1.3±0.7cm when compared to invasive activation±entrainment mapping. Conclusions: Use of computational 12-lead ECG mapping to guide ablation of unstable VT significantly improved freedom from ICD shocks and death resulting in excellent accuracy.

•Ruptured SVA into LA is a rare disorder and has high mortality.•Wide pulse pressure without severe AR is concerning for SVA rupture.•Continuous turbulent Doppler flow by echo can identify the rupture of SVA.•Severe MR without structural valve abnormality raises the possibility of SVA rupture.

Background: Left atrial appendage occlusion (LAAO) is increasingly used as an alternative to oral anticoagulation for stroke prevention in select patients with atrial fibrillation. Data on outcomes in racial and ethnic minority individuals are limited. This analysis assessed differences in the utilization and outcomes of LAAO by race and ethnicity in a large national registry. Methods: This analysis acquired data on WATCHMAN FLX patients from the National Cardiovascular Data Registry (NCDR) LAAO Registry through September 2022. All patients with an attempted WATCHMAN FLX implantation and known race and ethnicity were included. Baseline characteristics and 1 year event rates were compared. Results: A total of 97,185 patients were analyzed; 87,339 were White (90%), 3,750 Black (Black/African American 3.9%), and 2,866 Hispanic ([Hispanic/Latinx] 2.9%). Black and Hispanic patients were younger with a higher incidence of prior stroke and significant bleeding compared to White patients. Black and Hispanic patients were treated with LAAO in smaller numbers relative to their proportion of the US population. Rates of procedural success were similar between groups. Though direct oral anticoagulants were prescribed in most patients across the groups, dual and single antiplatelet therapy were prescribed more often in Black patients. Black patients had significantly higher rates of 1-year death and bleeding compared to White and Hispanic patients. Conclusions: Patients from racial and ethnic minority groups comprise a disproportionately small fraction of all patients who undergo LAAO. Black and Hispanic patients were younger but had significantly higher comorbidities compared to White patients. Procedural success was similar amongst the groups but Black patients experienced higher rates of death and bleeding at 1 year.### Competing Interest StatementThe authors have declared no competing interest.### Funding Statementnone### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:This study did not require IRB approvalI confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.YesAll data is available

Stroke remains a debilitating complication from atrial fibrillation (AF), and AF-related strokes are responsible for over 15% of all stroke cases in the United States.1,2 While systemic oral anticoagulation can mitigate the risk of stroke, many patients cannot tolerate these medications. Percutaneous left atrial appendage occlusion (LAAO) is an alternative to oral anticoagulation for stroke prophylaxis in AF patients who cannot tolerate these medications long-term. In the United States, the WATCHMANTM (Boston Scientific, Marlborough, MA) for LAAO is the only device currently approved by the United States Food and Drug Administration for this indication.