Russo, Antonio Dello

Abstract Background the electrophysiological substrate underpinning ventricular tachycardia (VT) in cardiac amyloidosis (CA) remains elusive, and outcomes of catheter ablation in this peculiar population are currently unknown. Purpose we sought to describe the electrophysiological substrate and clinical outcomes of VT ablation in a cohort of patients with CA. Methods we included 19 consecutive patients (mean age, 69±10 years; male sex, 89%) with CA (ATTR, n=13; AL, n=6) undergoing catheter ablation for VT/ventricular fibrillation (VF) between 2013 and 2023 in a retrospective, observational, international study, involving 7 referral European and North American electrophysiology units. The primary efficacy outcome was recurrent VT/VF during follow-up, while the primary safety outcome included major procedure-related adverse events. Results the indication for ablation was drug-refractory VT in 16 patients (84%), and PVC-initiated polymorphic VT/VF in 3 (16%). Catheter ablation was performed using endocardial (n=14, 74%) or endo-epicardial approaches (n=5, 26%). Complete endocardial electroanatomical voltage maps of the left and right ventricles were obtained in 14 (74%) and 6 (32%) patients, respectively. Each patient had evidence of low-voltage areas, most commonly involving the interventricular septum (n=12); late potentials were recorded in 13 patients (68%). A median of 1 (1-2) VTs were inducible per patient; in 10 subjects (43% of mappable VTs), activation mapping was consistent with septal VT origin. Complete procedural success was obtained in 13 patients (68%), at the expense of 4 (21%) major procedure-related adverse events. After a median follow-up of 36 (18-54) months, sustained VT/VF recurrence was observed in 9 patients (47%); survival free from VT/VF recurrence was 74% (95%CI, 56-96%) at 12 months, and 53% (95%CI, 34-94%) at 36-month follow-up; the majority of patients remained on antiarrhythmic drugs (Figure). Low-voltage QRS (HR,21.96; p=0.022) and complete procedural success (HR,0.08; p=0.029) were associated with recurrent VT/VF at multivariable analysis (Figure). Conclusions catheter ablation of VT/VF is associated with favorable acute and mid-term arrhythmia control, yet with substantial risk of procedure-related complications and long-term recurrences. Septal substrate and frailty challenge successful management of patients with CA and VT/VF.Multimodality evaluation of LV substrateMain Study Outcomes

Abstract Background and Aims Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC. Methods This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%–25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed. Results One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans. Conclusions North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

Introduction: The combination of local impedance (LI), a direct measure of electrical resistance at the catheter tip, and contact force (CF) may facilitate treatment of atrial fibrillation (AF). This trial is designed to examine the safety and effectiveness of a novel RF catheter that allows measurement of both LI and CF. Hypothesis: Demonstrate the safety and effectiveness of a novel radiofrequency catheter with LI and CF for treatment of drug refractory, recurrent, symptomatic Paroxysmal AF (PAF). Methods: NEwTON AF is a multi-center, global, prospective, single arm study. Patients received index treatment for PAF with the study catheter. The present 6-month endpoint analysis was prospectively planned. Results: The study treated 299 patients at 45 sites in North America, Europe, and Asia. Patients were 39.5% female with a mean age of 62yrs (±12), and had a mean LVEF of 59% and an LA diameter of 3.9cm. Procedure time, LA dwell, and fluoroscopy times were 166, 136, and 15 minutes, respectively. High-power short-duration (HSPD, 45-50W) was exclusively used in 210 cases, which had notably shorter procedure times than the 82 cases that used conventional power, 148 vs 208 min, respectively. Acute procedural success was observed in 98.3% of cases. As of 6 months, freedom from documented recurrence of any atrial arrhythmia was 79.9% (Figure). Recurrence in relation to LI shows that pts with a 20Ω LI drop (in at least 60% of lesions) had better 6m outcomes (84.2% vs 73.3, p=0.04). The freedom from safety event rate at 30d was 96.0%; events included pericarditis (6), access complications (2), pulmonary edema (2), embolism (2), cerebrovascular accident (1), tamponade (1). Pericarditis was higher in pts with a history of COVID at enrollment, 16.3% vs 5.9%, p=0.025. Conclusions: This data suggests that patient outcomes and safety for this novel catheter are promising. Further data from this study, including 12m outcomes, and detailed analysis of local impedance data are forthcoming.