Jan Chovancik

Background and Aims: In the PRAGUE-25 study, the effect of lifestyle modification (LFM) in combination with antiarrhythmic drugs (AAD) in patients with atrial fibrillation (AF) and BMI 30-40 was smaller than that of catheter ablation (CA). The presented sub-analysis aims to assess the relationship between the actual weight reduction and the AF burden 12 months after randomization. Methods: Per-protocol analysis of the PRAGUE-25 trial. Patients in the LFM+AAD group were stratified into tertiles based on the extent of relative weight reduction, and a comparison of AF burden was performed between the LFM+AAD tertiles and the CA group. Results: The study analyzed 83 LFM+AAD patients (age 60 ±9 years, 31% women, 54% paroxysmal AF, mean weight 109±17 kg) and 99 CA patients (age 60±9 years, 32% women, 56% paroxysmal AF, weight 109±15 kg). Within the LFM+AAD group, 28 patients achieved a weight reduction of >8.3% (−15.46±6.16 kg), 27 patients were between 3.1–8.1% (−6.56±2.28 kg), and 28 patients were <3.1% (+1.38±4.03 kg). Compared to the CA group, the AF burden at 12 months (0 [IQR 0–0]) was significantly higher in the second (3.5% [0; 52] and third (1[0; 47] LFM-ADD tertiles, but did not differ from CA in the first tertile (0% [0; 11.], p=0.17). Conclusion: In obese patients, the maintenance of SR on AADs is related to the level of weight reduction. The efficacy of AADs in obese patients with a significant weight loss at 12-months follow-up is close to catheter ablation, although the overall AF burden is still non-significantly higher.

Background: Idiopathic ventricular fibrillation (IVF) is a rare cause of sudden cardiac death and is a diagnosis of exclusion. With the availability of genetic testing, this condition is becoming increasingly rare. Nevertheless, in some cases, no identifiable cause is found. Management of recurrent IVF episodes poses a significant clinical challenge, often requiring advanced interventional approaches. Case summary: We present a 43-year-old male with a history of out-of-hospital cardiac arrest due to VF in 2015. Despite extensive examinations, including normal coronary angiography, cardiac MRI, and genetic testing, no underlying aetiology was identified. The patient received an implantable cardioverter-defibrillator (ICD) for secondary prevention. After an 8-year arrhythmia-free period, he experienced recurrent ICD shocks in 2023. Repeated diagnostics, including MRI and genetic testing, yielded inconclusive results. An electrophysiological study revealed abnormalities in the Purkinje fibre network, including a focal source within the conduction system and a localized scar in the lower mid-left ventricular septum. Radiofrequency ablation targeting these areas successfully terminated the electrical storm. Discussion: This case highlights the complexities in diagnosing and managing IVF, demonstrating a strong association between the Purkinje fibre network abnormalities in arrhythmogenesis. It underscores the importance of electrophysiological studies and catheter ablation in refractory cases, even when advanced imaging and genetic testing fail to reveal a clear aetiology. Conclusion: In patients with recurrent IVF refractory to conventional management, targeted ablation of Purkinje-related triggers not only terminates the storm, but provides durable rhythm control, as illustrated by our 8-month follow-up.

Funding Acknowledgements: Type of funding sources: None. Introduction: Malignant arrhythmic storm (MAS) increases mortality more than three-fold according to current data. In the acute setting, besides resolving reversible causes, antiarrhythmics are the mainstay of treatment. The role of suppressing the local sympathetic nervous system activity, using stellate ganglion block (SGB) for example, is still being investigated. Purpose: To show short-term efficacy of SGB in suppressing the ventricular arrhythmia recurrence in MAS. To identify subgroups of patients with better clinical response after SGB. Methods: All consecutive patients with MAS, with standard treatment failure and ventricular arrhythmia recurrence, treated with ultrasound guided SGB, instilating 7ml of 0,5% Bupivacain. 58 MAS treated with SGB durin 2017 – 2020. There were 49 men (84,5%), average age 68,7 +/- 11,4, with average left ventricular EF 28,9 +/- 8,43%. There were 17 diabetics (29,3%). Results: When we compare the numbers of defibrillations for sustained ventricular tachycardia 48 hours before and 48 hours after SGB, being the primary therapeutic endpoint in MAS, we see a 96,7% reduction (p < 0,001). When we evaluate ventricular arrhythmias treated with both antitachycardia pacing and shocks, then we see 90% reduction (p < 0,001). The effect of SGB in ventricular arrhythmia suppression was statistically significant during the entire follow-up of 8 days. When we analyzed the cohort, looking for groups showing better response after SGB in terms of ventricular arrhythmia reduction, the only group showing statistical significance in this regard are patients with diabetes mellitus. Conclusions: In our cohort, stellate ganglion block is exceptionally effective in the treatment algorithm of malignant arrhythmic storm. SGB shows significantly higher efficacy in the subgroup of patients with diabetes mellitus. Abstract Figure. VA before and after BSG

Purpose: Single center retrospective analysis of complications of catheter ablation for paroxysmal atrial fibrillation (PAF).

Background: Long-term efficacy of catheter ablation for atrial fibrillation (AF) greatly declines with time.

Purpose: Retrospective analysis of freedom from recurrent atrial fibrillation (AF) or atrial tachycardia (AT) after single catheter ablation for paroxysmal AF (PAF) in relation to procedural endpoint Methods: At first ablation in consecutive 946 patients (32% females, age 57 ± 10 years) it was at discretion of 4 involved operators whether they pursued AF/AT noninducibility following simple pulmonary vein isolation (PVI) performed during sinus rhythm (SR), or following termination of ongoing/induced AF/intermediate AT by simple PVI, or following termination of AF/AT continuing after completing PVI by ablation outside PVs. Noniducibility was tested by atrial pacing, isoproterenol and adenosine. Non-termination might be accepted after simple PVI or after PVI with extra-PV ablation. Three patients were excluded from analysis (ablation not performed: n = 2, no follow-up: n = 1). Results: PVI was completed in all patients. At the end of 69 ± 42 month follow-up after 1.36 procedures/patient stable SR was present in 85% patients (71% patients off drugs). No AF/AT recurrence vs. AF/AT recurrence after single ablation occurred in 71 vs. 29% of patients (p < 0.00001) in the group with proved noninducibility (n = 303), in 51 vs. 49% patients (p = 0.75) in the group of patients with non-tested/non-proved noninducibilty (n = 537), and in 31 vs. 69% patients (p = 0.001) in the group of non-terminated ongoing/induced AF/AT (n = 103) (Table). Conclusion: Noniducibility endpoint at first PAF ablation was associated with better single procedure arrhythmia-free outcome disregard presence or absence of AF during procedure. AF/AT non-termination was associated with the worst outcome.