Efficacy and safety of catheter ablation for Brugada syndrome: an updated systematic review

Long-term of epicardial radiofrequency ablation and benefit for recurrent ventricular arrhythmia in Brugada syndrome: A systematic review and meta-analysis

Background

Brugada syndrome (BrS) is a rare cardiac channelopathy linked to an increased risk of ventricular arrhythmias (VA) and sudden cardiac death. Radiofrequency ablation (RFA), particularly epicardial ablation, is recommended for BrS patients with recurrent VA unresponsive to conventional treatments like implantable cardioverter-defibrillators (ICD) and quinidine. This study aims to evaluate the long-term efficacy of epicardial RFA in preventing VA recurrence in BrS.

Methods

A systematic search of PubMed, ScienceDirect, Cochrane Library, and ProQuest databases was conducted following PRISMA 2020 guidelines. Studies on RFA for VA in BrS were included. Primary outcomes were VA recurrence and all-cause mortality. Statistical analysis was performed using Review Manager 5.4.

Results

Epicardial, endocardial, and combined ablation strategies effectively reduced VA recurrence, decreased ICD shocks, and improved clinical outcomes in BrS. Epicardial ablation RFA near coronary arteries showed a notable reduction in VA recurrence, while endocardial ablation remained a viable alternative. Meta-analysis revealed a significant reduction in VA recurrence (RR 0.17; 95% CI 0.07-0.43; p < .0001) and ICD shocks (RR 0.13; 95% CI 0.04-0.44; p = .001). Subgroup analysis suggested greater VA reduction with epicardial ablation, though without statistical significance.

Conclusion

Epicardial RFA is associated with a significant reduction in recurrent VAs (83%) and ICD shock rates (87%) in patients with BrS. The procedure demonstrates a favorable long-term safety profile, with no mortality reported in the included studies.

Cardiac sarcoidosis in patients with recurrent ventricular arrhythmias refractory to endocardial ablation

INTRODUCTION

The clinical presentation of cardiac sarcoidosis is diverse. Detection of granuloma in histopathological evaluation proves the diagnosis, but endomyocardial biopsy (EMB) is associated with a high sampling error. However, prompt immunosuppressive therapy may significantly affect patient's prognosis. By analyzing our single center cohort of patients with recurrent ventricular arrhythmias (VA) and nonischemic cardiomyopathy after failure of endocardial ablation, we looked for additional markers supporting the diagnosis of cardiac sarcoidosis.

METHOD

In the last 4 years, 135 patients (mean age 49 y, 63% male) were hospitalized for epicardial ventricular arrhythmia (VA) ablation after failure of endocardial ablation. Nineteen patients had either previously received a diagnosis of cardiac sarcoidosis or were newly diagnosed. The mean follow-up time was 4.3 years. The ECG criteria, primary manifestation, histological findings in EMB, history of VT ablation, distribution of scars on MRI, electroanatomical mapping (EAM), PET CT findings, presence of atrial tachycardias, valve disease and comorbidities were analyzed.

RESULTS

Six of 19 (32%) patients showed right bundle block; 6 of 19 (32%) had AV nodal disease, including 4 patients with AV-block III; and 14 patients (73%) primarily presented with ventricular arrhythmias (including 3 with cardiac arrest). In all 19 patients cardiac EMB revealed elevated CD68 macrophages and CD3 T lymphocytes, and 7 of 19 were positive for granuloma (36,8%). Six of 6 patients (100%) undergoing PET CT showed acute inflammation. By analyzing the scar distribution, the most common locations were basal anteroseptal, basal inferoseptal, mid inferoseptal, mid inferior and the septal RV/RVOT. (septal substrate in 100%). There was a high correlation between the findings on the MRIs and low voltage in the electroanatomical mapping EAM). All patients received an immunosuppressive therapy. No patient died during follow-up, 1 patient had a high urgent heart transplant after withdrawal of steroid therapy.

CONCLUSION

Chronic untreated inflammation may be the underlying pathophysiology for patients with unspecific cardiomyopathy and recurrent VA refractory to endocardial and epicardial ablation. Septal substrate in the EAM/MRI, elevated CD3 lymphocytes in the EBM and inflammation in the PET CT may indicate the possible diagnosis of cardiac sarcoidosis. Initializing immunosuppressive therapy in patients with this dedicated constellation with should be taken into consideration.

High-risk Brugada syndrome: factors associated with arrhythmia recurrence and benefits of epicardial ablation in addition to implantable cardioverter defibrillator implantation

AIMS

This study aims to evaluate the prognostic impact of the arrhythmogenic substrate size in symptomatic Brugada syndrome (BrS) as well as to validate the long-term safety and effectiveness of epicardial radiofrequency ablation (RFA) compared with no-RFA group.

METHODS AND RESULTS

In this prospective investigational long-term registry study, 257 selected symptomatic BrS patients with implantable cardioverter defibrillator (ICD) implantation were included. Among them, 206 patients underwent epicardial RFA and were monitored for over 5 years post-ablation (RFA group), while 51 patients received only ICD implantation declining RFA. Primary endpoints included risk factors for ventricular fibrillation (VF) events pre-ablation and freedom from VF events post-ablation. In the RFA group, BrS substrates were identified in the epicardial surface of the right ventricle. During the pre-RFA follow-up period (median 27 months), VF episodes and VF storms were experienced by 53 patients. Independent risk factors included substrate size [hazard ratio (HR), 1.13; 95% confidence interval (CI), 1.08-1.18; P < 0.001], aborted cardiac arrest (HR, 2.98; 95% CI, 1.68-5.28; P < 0.001), and SCN5A variants (HR, 2.22; 95% CI, 1.15-4.27; P = 0.017). In the post-RFA follow-up (median 40 months), the RFA group demonstrated superior outcomes compared with no-RFA (P < 0.001) without major procedure-related complications.

CONCLUSION

Our study underscores the role of BrS substrate extent as a crucial prognostic factor for recurrent VF and validates the safety and efficacy of RFA when compared with a no-RFA group. Our findings highlight the importance of ajmaline in guiding epicardial mapping/ablation in symptomatic BrS patients, laying the groundwork for further exploration of non-invasive methods to guide informed clinical decision-making.

Current gaps in knowledge in inherited arrhythmia syndromes

The 3 most common inherited arrhythmia syndromes-Brugada syndrome, congenital long QT syndrome and catecholaminergic polymorphic ventricular tachycardia-were initially described in the previous century. Since then, research has evolved, which has enabled us to identify patients prior to the onset of potentially life-threatening symptoms. However, there are significant gaps in knowledge that complicate clinical management of these patients today. With this review paper, we aim to highlight the most important knowledge gaps in clinical research of these inherited arrhythmia syndromes.

Trigger and Substrate Mapping and Ablation for Ventricular Fibrillation in the Structurally Normal Heart

Sudden cardiac death (SCD) represents approximately 50% of all cardiovascular mortality in the United States. The majority of SCD occurs in individuals with structural heart disease; however, around 5% of individuals have no identifiable cause on autopsy. This proportion is even higher in those <40 years old, where SCD is particularly devastating. Ventricular fibrillation (VF) is often the terminal rhythm leading to SCD. Catheter ablation for VF has emerged as an effective tool to alter the natural history of this disease among high-risk individuals. Important advances have been made in the identification of several mechanisms involved in the initiation and maintenance of VF. Targeting the triggers of VF as well as the underlying substrate that perpetuates these lethal arrhythmias has the potential to eliminate further episodes. Although important gaps remain in our understanding of VF, catheter ablation has become an important option for individuals with refractory arrhythmias. This review outlines a contemporary approach to the mapping and ablation of VF in the structurally normal heart, specifically focusing on the following major conditions: idiopathic ventricular fibrillation, short-coupled ventricular fibrillation, and the J-wave syndromes-Brugada syndrome and early-repolarization syndrome.