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ABSTRACT Background Early catheter ablation for atrial fibrillation (AF) improves outcomes, but the optimal timing, especially in heart failure (HF) subtypes, remains unclear. Objective To evaluate the impact of ablation timing on outcomes in patients with HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Methods We used the TriNetX database (2010–2024) to identify HF patients with AF who underwent ablation. Patients were classified as early ablation (≤ 1 year of first AF diagnosis) or delayed ablation (1–3 years), with propensity score matching (PSM) applied to balance the baseline characteristics. The primary outcome was AF recurrence, defined by repeat ablation, direct current cardioversion (DCCV), or antiarrhythmic drug (AAD) use after a 3‐month blanking period. Secondary outcomes included stroke, hospitalization, and mortality over 5 years. Results After PSM, delayed ablation was associated with higher AF recurrence in both HFrEF (HR = 1.28, p < 0.001) and HFpEF (HR = 1.21, p = 0.02), as seen in multivariate analysis. In HFrEF, delayed ablation was associated with higher incidence of re‐do ablation, AAD use, and DCCV, while in HFpEF, higher recurrence with delayed ablation was associated with increased AAD use. Both cohorts had similar stroke and mortality rates between early and delayed ablation. Conclusions Delayed ablation in HFrEF and HFpEF was linked to higher AF recurrence, driven by increased redo ablations, DCCV, AAD use in HFrEF, and higher AAD use in HFpEF. Stroke, HF hospitalization and mortality rates were similar, suggesting earlier ablation may enhance rhythm control over other outcomes.

Background: Patients with systemic right ventricle (sRV), including congenitally corrected transposition of great arteries (cc-TGA) and dextro-transposition of great arteries (d-TGA) post-atrial switch procedure are at risk of sudden cardiac death due to ventricular arrhythmias (VA). While programmed ventricular stimulation (PVS) can help with risk stratification in certain patients with congenital heart disease, its role in sRV is unknown. Objective: To study the diagnostic value of electrophysiology study (EPS) in predicting VAs in patients with sRV. Methods: EPS was performed in 53 patients with sRV at Mayo Clinic from 1994 to 2021. Patients with a history of sustained VA or cardiac arrest were excluded (n=19). The incidence of sustained VA (sudden cardiac death, sustained ventricular tachycardia [VT] or appropriate implantable cardioverter-defibrillator [ICD] therapy) was evaluated in the remaining 34 patients. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of EPS in predicting VAs is reported. Results: The mean age at EPS was 36.2±11.6 years, 21 (61.8%) were male, 21 (61.8%) had d-TGA and mean sRV ejection fraction was 31.3±10.8%. Indication for EPS was supraventricular tachycardias (n=15, 44.1%), syncope/palpitations (n=9, 26.5%) and non-sustained VT (n=6, 17.6%). 13/34 (38.2%) patients had inducible sustained VA, (5 [38.5%] with monomorphic VT and 8 [61.5%] with polymorphic VT/VF). Treatments included ICD implantation in all 13 patients and ablation in one patient. During a mean follow-up of 8±5.4 years, one patient with a positive PVS (inducible polymorphic VT) experienced sustained VT secondary to atrial flutter with 1:1 conduction. The sensitivity of PVS was 100%, specificity was 63.6%, PPV 7.7%, and NPV 100%. Conclusion: In this retrospective cohort of patients with sRV, polymorphic VT was the most commonly observed VA during PVS. The predictive value of a positive PVS was low in this cohort, and larger studies are needed to better define the role of EPS in risk stratification. Patients with negative EPS did not have future VAs recognizing that the overall event rate is low. Further multicenter research with a larger sample is required to develop predictive models to identify those at risk of VAs.

Background: Ventricular tachycardia (VT) is a major contributor to death among ischemic heart disease (IHD) patients. In this systematic review and meta-analysis, we evaluate the efficacy of catheter ablation in patients with ischemic cardiomyopathy. Methods: We conducted a meta-analysis by searching the electronic database up to April 2025. Seven studies, including 1192 patients, were identified. A random-effect model was used to estimate pooled risk ratios (RRs) and 95% confidence intervals (CIs). Trial sequential analysis was conducted to assess sample size adequacy. Results: Among Ischemic heart disease patients with ICDs, VT ablation was associated with a significant reduction in ICD shocks (RR = 0.50, 95% CI [0.34–0.74]), a trend toward reduced VT storm (RR = 0.64, 95% CI [0.40–1.04], p = 0.07), and lower rates of cardiovascular hospitalization (RR = 0.73, 95% CI [0.53–1.01], p = 0.06) compared to ICD alone. However, no significant differences were observed when compared to patients receiving ICD plus antiarrhythmic drugs (AADs). Additionally, VT ablation showed no significant impact on mortality or VT/VF recurrence compared to either ICD alone or ICD with AADs. Trial Sequential Analysis provided conclusive evidence for VT/VF recurrence outcomes, while further data are required for other outcomes. Conclusion: Among ischemic heart disease patients with ICD, VT ablation reduces ICD shocks, VT storm, and cardiovascular hospitalizations compared to ICD-only, but offers no significant advantage over ICD combined with antiarrhythmic drugs. VT ablation does not impact mortality or the recurrence of VT/VF. Trial Sequential Analysis confirmed conclusive evidence for VT/VF recurrence, while additional data is needed for other outcomes.

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia with prevalence increasing over the last decade. However, data on recent temporal trends in incidence of AF have been inconsistent, with some reports of increasing trends over time and others indicating no change in incidence over time. Therefore, we aimed to determine how the incidence of AF has changed over the last decade in a community in the Midwest USA. Methods: Between 2013 and 2023, adults (aged 18 and older) with incident AF were identified in a 27-county region in the Midwest. AF was identified using diagnostic codes by employing an electronic algorithm requiring 1 inpatient code or 2 outpatient codes separated by >7 days but within 1 year. For total rates, age - and sex-adjusted incidence rates were standardized to the 2010 US total population. Poisson regression was used to calculate the incidence rate ratio of AF for 2023 vs 2013. Results: We identified 44,930 individuals with incident AF from 2013 to 2023. Of these, 56.4% were male, the mean (SD) age was 72.8 (13.5) years, and 95.8% were non-Hispanic white. The age-and sex-adjusted incidence rates (per 1,000) and 95% confidence intervals standardized to the 2010 US total population were 5.24 (5.07-5.41) in 2013, 5.73 (5.56-5.91) in 2018, and 5.44 (5.28-5.61) in 2023. Although a drop in incidence was observed corresponding to the COVID-19 pandemic, a small increase in the overall incidence of AF was observed over time. The overall incidence rate ratio (95% CI) for 2023 vs 2013 was 1.07 (1.02-1.11), P=0.003. The incidence rates were higher in men compared to women and increased with older age ( Figure 1 ). However, differences in AF incidence by sex were greatest in the youngest age group and attenuated with older age (incidence rate ratio (95% CI): 2.18 (2.10-2.28) for ages 18-64 years, 1.76 (1.70-1.83) for ages 65-74 years, 1.38 (1.33-1.42) for ages 75-84 years, and 1.23 (1.18-1.28) for ages 85 years and older). Conclusion: In this 27-county region in the Midwest, although small in magnitude, a statistically significant increase in AF incidence was observed over time from 2013 to 2023. Furthermore, the incidence of AF was higher in men compared with women, especially in younger age groups.

Backround: Advances in surgical and medical care of children born with congenital heart disease (CHD) has improved survival into adulthood. However, cardiac and non-cardiac morbidity and mortality remain common in adults with CHD (ACHD). We present the causes and predictors of mortality in a large cohort of ACHD patients from the USA. Methods/Approach: We conducted a retrospective review of ACHD patients followed at Mayo Clinic between 1992 - 2024. Mortality was ascertained using the Accruint national data base. Clinical characteristics and primary cause of death were identified from the electronic record. Kaplan-Meier (KM) survival analysis was performed to compare overall survival stratified by CHD severity. Cox proportional hazards regression was used to identify independent predictors of mortality. Results/Data: Amongst 9160 ACHD patients (mean age 38±16y at first visit, 51% males, 23% simple, 59% moderate and 18% severe CHD), mortality occurred in 1430(16%) patients during a mean follow-up of 11±7y. The mean age at death was 68±17 y, 58±17y, and 45±15y in mild, moderate and severe ACHD. KM analysis of survival and cause of death stratified by CHD severity are presented in Figures 2 and 3 respectively. Cause of death could not be ascertained in 33%%. Amongst those with a known cause of death, the proportion of non-cardiac death increased with decreasing severity of CHD. HF death and sudden cardiac death occurred in 11% and 19%. Infection, malignancy and chronic respiratory failure were important non-cardiac causes of death. Significant risk factors for mortality included CHD severity, ventricular arrhythmia, heart failure, declining functional capacity, diabetes and chronic kidney disease as presented in the Fig 1. Conclusion(s): Mortality in ACHD patients is associated with CHD severity, heart failure, ventricular arrhythmia and cardiovascular comorbidities. Early recognition and management of these risk factors may improve long-term survival. As patients with ACHD age, management of cardiovascular and noncardiac risk factors will require development of systems of care specific to this vulnerable population.

Background: Patients with repaired Tetralogy of Fallot (TOF) undergoing pulmonary valve replacement (PVR) are at increased risk of major adverse ventricular arrhythmias and related events (MAREs). Perioperative electrophysiological study (EPS) has been used for risk stratification and guiding future management, but these studies are limited by small sample size. Objectives: To perform a systematic review of outcomes of pre-PVR EPS in TOF patients with PVR. Methods: A comprehensive search of PubMed, Embase, Scopus and Google scholar databases was performed per PRISMA 2020 guidelines. Studies on patients with repaired TOF undergoing PVR with perioperative EPS were included. Data were extracted on study design, sample size, EPS outcomes and MAREs during follow-up. Results: A total of 1,528 patients (age: 35.5±3.8 y; 57% male; LVEF: 57.1±1.5%, RVEF: 42.6±1.5%) were included from 12 studies. EPS was performed in 1212/1528 (79.3%), with sustained VT inducibility in 404 (33.3%)-monomorphic VT in 258 (63.8%), while 808 (66.6%) were non- inducible. 8/12 studies reported the type of PVR (transcatheter-36.8%). 174/293 (59.3%) inducible patients had an ablation (9 studies), while ICD (6 studies) was implanted in 70/263 (26.6%). Follow-up EPS (6 studies) showed 35/230 (15.2%) remained inducible. Overall,113 (9.3%) patients experienced MAREs over a median follow-up ranging from 6 months to 6.7 years. Sustained VT (11/12 studies) occurred in 70/1092 (6.4%), appropriate ICD therapy (7/12 studies) in 13/622 (2.1%) and sudden cardiac death (10/12 studies) in 30/906 (3.3%). Five studies provided MARE data stratified by VT inducibility. 12/164 (7.3%) inducible patients experienced MAREs, compared to 2/318 (0.6%) non-inducible patients. Reported risk factors for MAREs included older age at initial repair and PVR, QRS duration (>180ms), LVEF <45%, RVEF <35%, history of syncope, prior palliative shunts and atrial arrhythmias. Some studies identified MRI-derived scar burden, pulmonary annulus size, and RV/LV volume ratios as additional predictors. Conclusion: TOF patients remain at high risk of VA after PVR with 1/10 patients experiencing MAREs. People with inducible VT had a 12-fold greater risk than people who were non-inducible. EPS identifies a subset of TOF patients at higher arrhythmic risk during PVR and supports tailored ablation and ICD strategies. Prospective multicentre studies are needed to optimize integration of EPS and clinical risk models.

Background: Papillary Muscle (PM) related ventricular arrhythmia ablation is associated with lower acute success and suboptimal long-term outcomes due to complex anatomy, variable arrhythmogenic sites and dynamic exit points. Objective: To evaluate clinical and procedural outcomes of patients undergoing PM vs non-PM ablation. Methods: A retrospective analysis of adults (≥18 years) undergoing PVC ablation at Mayo Clinic (2019–2024) matched PM PVC ablations to controls (1:2) using propensity scoring based on age, sex, comorbidities and baseline LVEF. Chi-square and t-tests compared baseline and procedural characteristics. Logistic regression estimated odds ratios for immediate procedural success, PVC burden reduction and LVEF improvement at 3 months. Results: Of the 720 ablations, 392 cases were included after propensity matching: 132 PM and 260 non-PM. Patients in the PM group exhibited higher rates of complicated diabetes (9.8% vs 4.6%, p =0.045) and prior MI (18.2% vs 9.2%, p =0.011). Preprocedural ECG PVCs in the PM group showed a shorter intrinsicoid deflection (89.1 ± 35.0 msec vs 100.7 ± 24.3 msec, p <0.001) and longer coupling intervals (532.7 ± 100.3 vs 512.2 ± 81.4 msec, p =0.048).Moderate-to-severe MR was more prevalent in the PM group (17.4% vs 10.0%, p =0.036). Intraoperatively, the PM group had higher total energy delivery times (1939 ± 1336 sec vs 1227 ± 1033 sec, p <0.001) and more frequent cryoablation use (46.2% vs 7.3%, p <0.001). During post-ablation testing, non-clinical PVC was inducible in 39.5% of the cases in PM group compared to 25.7% in non-PM group ( p =0.005). More patients in the PM group were discharged on atleast one antiarrhythmic drug (AAD)(35.9% vs 18.5%, p <0.001) and AAD use persisted at 3 months (31.3% vs 18.4%, p =0.004). Outcomes were similar between groups, with no significant differences observed in immediate ablation success (aOR 0.64, p = 0.063, CI = 0.40-1.03), or >5% improvement in LVEF (aOR 0.76, p = 0.29) and PVC burden reduction (aOR 0.93, p = 0.81) at 3 months follow up. Conclusion: Patients undergoing PM ablation exhibited higher baseline rates of comorbidities. Intraoperatively they required greater energy delivery times, and an increased use of cryoablation. Postoperatively, a larger proportion of PM ablation patients required antiarrhythmic drug therapy. Despite these complexities, PM ablation showed no significant differences in PVC burden reduction, LVEF improvement, or procedural success compared to non-PM ablation.

Background: Early catheter ablation for atrial fibrillation (AF) improves outcomes, but the optimal timing, especially in heart failure (HF) subtypes, remains unclear. Objective: To evaluate the impact of ablation timing on outcomes in patients with HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Methods: We used the TriNetX database (2010–2024) to identify HF patients with AF who underwent ablation. Patients were classified as early ablation (≤1 year of first AF diagnosis) or delayed ablation (1–3 years), with propensity score matching (PSM) applied to balance the baseline characteristics. The primary outcome was AF recurrence, defined by repeat ablation, direct current cardioversion (DCCV), or antiarrhythmic drug (AAD) use after a 3-month blanking period. Secondary outcomes included stroke, hospitalization, and mortality over 5 years. Results: After PSM, delayed ablation was associated with higher AF recurrence in both HFrEF (HR 1.25, p < 0.001) and HFpEF (HR 1.27, p = 0.01), as seen in multivariate analysis. In HFrEF, delayed ablation was associated with higher incidence of re-do ablation, AAD use, and DCCV, while in HFpEF, higher recurrence with delayed ablation was associated with increased AAD use. Both cohorts had similar stroke and mortality rates between early and delayed ablation. Conclusions: Delayed ablation in HFrEF and HFpEF was linked to higher AF recurrence, driven by increased redo ablations, DCCV, AAD use in HFrEF, and higher AAD use in HFpEF. Stroke and mortality rates were similar, suggesting earlier ablation may enhance rhythm control without affecting long-term survival.

Background: Dofetilide, a commonly prescribed class III antiarrhythmic for atrial fibrillation (AF), currently requires a 3-month amiodarone washout period per FDA guidelines. We evaluated the safety of initiating dofetilide within this 3-month washout period. Methods: We performed a retrospective cohort study across all Mayo Clinic sites and identified patients using centralized datamart that were transitioned from amiodarone to dofetilide in less than 90 days. Patients were included and confirmed by manual chart review if they had been on amiodarone for ≥ 12 weeks and if available amiodarone level >0.3 mg/ml at the time of dofetilide initiation. Serial ECGs were assessed during the hospitalization for dofetilide initiation and at 3-, 6-, and 12-months follow-up to evaluate QT interval. Primary safety end point was torsade de pointes. Results: The final cohort included 66 patients with a mean age of 65 ±14 years; 71.0% were male; and the average BMI was 29.6 ±5.1 kg/m 2 . Of the 66 patients, 65 had a history of AF: 31.8% paroxysmal, 54.5% persistent, and 12.1% long-standing persistent. Permanent pacemakers and ICDs were present in 27.3% and 22.7% of patients. Patients received amiodarone for a median of 7.8 months at a mean daily dose of 187.1±48.3 mg (range: 100 – 400 mg), with a mean transition period of 44.2±20.3 days. Of 66 patients, 16 (24 %) transitioned within 30 days of stopping amiodarone—including 5 (8 %) within 14 days—while the remaining 50 (76 %) was between 30 and 90 days. A total of 24.2% (16/66) patients required dofetilide dose reduction due to QT prolongation and 10.6% of patients (7/66) required drug discontinuation. There was no difference in either discontinuation rate or dose reduction rate in patients with a transition period ≤30 days vs > 30 days [6.25% vs. 12% (p=0.85) and 12.5% vs. 28% (p=0.36), respectively]. No cases of torsades de pointes were observed during dofetilide initiation or follow up. Conclusion: In this cohort, dofetilide initiation less than 90 days after amiodarone discontinuation was not associated with increased torsades de pointes risk. These data challenge and support reconsideration of the blanket 3-month washout and suggest that a monitored, expedited rhythm-control transition is feasible and safe.

Background: Leadless pacemaker has emerged as a promising alternative to traditional transvenous pacemaker (PM) among elderly patients who are at high risk of complications. Objective: This study aims to assess and compare 5-year clinical outcomes of leadless PM versus transvenous single-chamber PM in elderly patients using a multi-national dataset. Methods: Using the TriNetX Analytics Research Network, we included patients aged ≥65 years who underwent leadless versus transvenous single-chamber PM implantation between 1/1/2014 and 1/1/2020. Propensity score matching (PSM) was performed by using patient’s demographic, LVEF, cardiac comorbidities, and medications. The study outcomes included all-cause mortality and adverse cardiovascular events over a 5-year follow-up period. Results: After PSM, 7,501 patients in each group were analyzed. Leadless PM was associated with a significantly lower odds of 5-year all-cause mortality (odds ratio [OR]: 0.534; 95% confidence interval [CI]: 0.497-0.575), heart failure exacerbation (OR: 0.779, 95% CI: 0.721-0.841), major bleeding (OR: 0.666, 95% CI: 0.604-0.734), cardiac arrest (OR: 0.747, 95% CI: 0.646-0.864) and stroke (OR: 0.825, 95% CI: 0.750-0.908) compared to transvenous single-chamber PM. No significant difference was observed between the two groups in all-cause hospitalization (OR: 1.006, 95%CI: 0.938-1.079), cardiac thrombus (OR: 1.077, 95%CI: 0.791-1.465) or venous thromboembolism (OR: 1.028, 95%CI: 0.916-1.153). Conclusion: Leadless PM was associated with significantly improved mortality and cardiovascular outcomes compared to transvenous single-chamber PM in elderly patients. These findings support the strong consideration of leadless pacing as a strategy to reduce mortality and improve clinical outcomes in this high-risk population.