Quelal, Karol

BACKGROUND: Ventricular fibrillation (VF) remains a leading cause of sudden cardiac death with an incompletely characterized electrophysiological substrate. Traditional large-animal VF models are limited by hemodynamic collapse and myocardial ischemia. This study establishes a reproducible swine model using dual mechanical circulatory devices to enable high-density electroanatomic mapping under nonischemic conditions. METHODS: Five Yorkshire swine (55–65 kg) underwent sustained VF supported by venoarterial extracorporeal membrane oxygenation (2.5–3.0 L/min) and percutaneous left ventricular unloading (Impella CP, P-2–P-4). High-density electroanatomic mapping using CARTO 7 was performed at baseline and after defibrillation. Bipolar voltage was acquired from 7 predefined ventricular regions (21 measurements per animal per time point; n=210 paired observations). Unipolar voltage mapping and continuous surface ECG monitoring were used to assess acute ischemic injury. Systemic perfusion was maintained at systolic arterial pressure ≥80 mm Hg. Linear mixed-effects modeling was used to analyze voltage changes from pre-VF to post-VF. RESULTS: Sustained VF (10±1 minutes) was reproducibly induced and maintained with consistent hemodynamics (systolic arterial pressure, 90±5 mm Hg; extracorporeal membrane oxygenation flow, 2.5±0.5 L/min). All animals were successfully defibrillated. High-density mapping was feasible in all experiments (1000±300 points per chamber). Bipolar voltage showed no change from pre-VF (5.86±2.56 mV) to post-VF (6.53±2.22 mV; mean difference, 0.67 mV [95% CI, –0.31 to 1.65]; P =0.15). Both left ( P =0.17) and right ventricles ( P =0.08) demonstrated voltage preservation. Regional analysis showed no significant changes (all P >0.05); post-VF voltages remained above viability thresholds (>1.5 mV). Unipolar voltage maps recovered toward baseline, with no ECG injury pattern identified after defibrillation. CONCLUSIONS: Dual mechanical circulatory support with venoarterial extracorporeal membrane oxygenation and Impella CP enables reproducible, high-fidelity electroanatomic mapping and preserves myocardial substrate after sustained VF in a large-animal model. This platform overcomes key technical barriers in VF research, providing a nonischemic foundation for future mechanistic and translational studies.

ABSTRACT Introduction Frailty is increasingly recognized as an important determinant of outcomes in cardiovascular disease, yet its population‐level impact among patients hospitalized with cardiac implantable electronic device (CIED) infections remains incompletely defined. We examined the prevalence of frailty and its association with clinical outcomes and utilization of transvenous lead removal (TLR) in a contemporary national cohort. Methods and Results We analyzed the National Readmissions Database from 2016–2021 to identify adults hospitalized for CIED infections. Frailty was defined using the Johns Hopkins adjusted clinical groups frailty‐defining diagnoses. Of 288,402 patients hospitalized with CIED infections, 25.1% were classified as frail. Frail patients experienced significantly higher in‐hospital mortality (10.8% vs. 4.6%), 30‐day mortality (9.2% vs. 5.5%), complications, longer length of stay, lower rates of discharge home, and higher 30‐day readmissions compared with non‐frail patients (all p < 0.01). TLR was performed less frequently in frail patients (10.8% vs. 13.4%; adjusted odds ratio [aOR] 0.80, 95% CI 0.76–0.83). On adjusted analyses, TLR was independently associated with lower in‐hospital mortality, 30‐day mortality, and 30‐day readmissions in both frail and non‐frail patients. Conclusion Among patients hospitalized with CIED infections, TLR was independently associated with lower mortality and readmissions in both frail and non‐frail patients, despite lower utilization in frail individuals. Frailty was common (25.1%) and independently associated with significantly worse outcomes. These findings highlight important associations between frailty, treatment patterns, and outcomes that warrant prospective evaluation.

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: 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: Catheter ablation of frequent premature ventricular complexes (PVCs) has been demonstrated to improve left ventricular ejection fraction (LVEF) in patients with PVC-induced cardiomyopathy. However, this improvement is not uniformly observed across all patients. Objective: To identify predictors of LVEF improvement following catheter ablation. Methods: This retrospective analysis included adult patients (≥18 years) who underwent PVC catheter ablation at Mayo Clinic, Rochester, between 2021 and 2024. Patients were grouped based on whether they experienced an LVEF improvement of ≥5%. Data on baseline comorbidities,, ECG characteristics, baseline transthoracic echocardiography (TTE), procedural details, and follow-up outcomes at 3-6 months (via Holter monitoring and TTE) were collected. Propensity matching (1:1) was performed using age(caliper=5), sex, and baseline LVEF(caliper=5). Comparative analyses used chi-square and t-tests. Variables with a p-value <0.1 were included in multivariate regression analysis. Results: After propensity matching, 98 patients with LVEF improvement and 98 controls were included. Table 1 summarizes baseline and procedural characteristics, and outcomes. Immediate PVC suppression was more common in the EF improvement group (74.2% vs. 60.4%, p=0.04), and fewer patients in this group were placed on long-term anti-arrhythmic medications (11.2% vs. 27.8%, p<0.01). Multivariate analysis showed that patients without PVC-related symptoms (OR=3.16, p=0.038) had higher odds of LVEF improvement, while those with CKD (OR=0.36, p=0.007) or a coupling interval ≥500 ms (OR=0.38, p=0.002) had lower odds of improvement.

ABSTRACT Background Valve‐in‐valve transcatheter aortic valve replacement (ViV‐TAVR) is increasingly used to treat structural valve degeneration. Permanent pacemaker implantation (PPI) following TAVR is associated with increased morbidity and mortality, yet predictors specific to ViV‐TAVR remain poorly defined. Objective To identify clinical and procedural predictors of PPI in patients undergoing ViV‐TAVR. Methods We conducted a retrospective observational study of consecutive ViV‐TAVR cases at the Mayo Clinic from 2012 to 2022. Clinical, ECG, procedural data and fluoroscopic measurements were analyzed, and propensity score matching was used to adjust for confounding. Predictors of PPI were identified using multivariable logistic regression. Results Among 261 patients, 24 (9.2%) underwent PPI. Balloon‐expandable valves were used in 66.7% and self‐expanding valves in 33.3%. Predictors of PPI included Preprocedural bifascicular block (OR 12.15, 95% CI: 2.52–68.89, p = 0.003), greater septal implantation depth (OR 1.29, 95% CI: 1.04–1.65, p = 0.019), and post‐procedural new left (OR 23.56, 95% CI: 4.91–48.52, p = 0.0004) and right bundle branch blocks (OR 24.4, 95% CI: 3.82–30.51, p = 0.001). Aortic regurgitation as the mechanism of prosthetic valve failure was associated with reduced PPI odds (OR 0.28, 95% CI: 0.10–0.76, p = 0.014). Pacing requirement—defined as > 90% ventricular pacing—increased from 25% at 3 months to 56.25% at 12 months. At a median follow‐up of 962.5 days (IQR 481.5–1555.3), adjusted mortality was significantly higher in the PPI group (aOR 9.4, 95% CI: 1.9–60.4, p = 0.028). Conclusion Bifascicular block, greater septal depth, and new bundle branch blocks predict PPI post‐ViV‐TAVR, while aortic regurgitation appears protective. Risk stratification and procedural planning are critical.

ABSTRACT Background Ventricular tachycardia (VT) is a major contributor to sudden cardiac death among patients with ischemic heart disease (IHD). While catheter ablation reduces the arrhythmic burden, the impact on long‐term outcomes remains uncertain. We assess the efficacy of catheter ablation in patients with IHD. Methods We performed a meta‐analysis by systematically searching electronic databases from inception to April 2025. Pairwise, reconstructed time‐to‐event data meta‐analyses and Trial Sequential analyses were conducted. Results A total of seven studies (1192 participants) were included. Among patients with IHD with ICD, 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). VT ablation showed no significant impact on mortality or VT/VF recurrence compared to either ICD alone or ICD with AADs. Reconstructed Kaplan–Meier analysis for all‐cause mortality showed no significant difference between VT ablation and AAD + ICD. Trial Sequential Analysis provided conclusive evidence for VT/VF recurrence, while further data is required for other outcomes. Conclusion Among patients with IHD with ICD, VT ablation reduces ICD shocks, VT storm, and cardiovascular hospitalizations compared to ICD‐only therapy, but offers no significant advantage over ICD combined with AADs. VT ablation does not impact overall 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 Valve-in-valve transcatheter aortic valve replacement (ViV-TAVR) is increasingly used to treat structural valve degeneration. Permanent pacemaker implantation (PPI) following TAVR is associated with increased morbidity and mortality, yet predictors specific to ViV-TAVR remain poorly defined. Objective To identify clinical and procedural predictors of PPI in patients undergoing ViV-TAVR. Methods We conducted a retrospective observational study of consecutive ViV-TAVR cases at the Mayo Clinic from 2012 to 2022. Clinical, ECG, procedural data and fluoroscopic measurements were analyzed, and propensity score matching was used to adjust for confounding. Predictors of PPI were identified using multivariable logistic regression. Results Among 261 patients, 24 (9.2%) required PPI. Balloon-expandable valves were used in 66.7% and self-expanding valves in 33.3%. Predictors of PPI included pre-procedural bifascicular block (OR 12.15, 95% CI: 2.52–68.89, p=0.003), greater septal implantation depth (OR 1.29, 95% CI: 1.04–1.65, p=0.019), and post-procedural new left (OR 23.56, 95% CI: 4.91–48.52, p=0.0004) and right bundle branch blocks (OR 24.4, 95% CI: 3.82–30.51, p=0.001). Aortic regurgitation as the mechanism of prosthetic valve failure was associated with reduced PPI odds (OR 0.28, 95% CI: 0.10–0.76, p=0.014). Pacing requirement—defined as >90% ventricular pacing—increased from 25% at 3 months to 56.25% at 12 months. At a median follow-up of 962.5 days (IQR 481.5–1555.3), adjusted mortality was significantly higher in the PPI group (aOR 9.4, 95% CI: 1.9–60.4, p=0.028). Conclusion Bifascicular block, greater septal depth, and new bundle branch blocks predict PPI post-ViV-TAVR, while aortic regurgitation appears protective. Risk stratification and procedural planning are critical.