Catheter ablation for monomorphic ventricular tachycardia in Brugada syndrome patients: detailed characteristics and long-term follow-up

Catheter ablation as an adjunctive therapy to ICD implantation in Brugada Syndrome

BACKGROUND

Brugada Syndrome (BrS) is a life-threatening cardiac arrhythmia disorder associated with an increased risk of ventricular arrhythmias (VAs) and sudden cardiac death. Current management primarily relies on implantable cardioverter-defibrillators (ICDs), but patients may experience ICD shocks. Catheter ablation (CA) has emerged as a potential intervention to target the arrhythmogenic substrate. This systematic review aims to evaluate the safety and efficacy of CA in BrS patients.

METHODS AND RESULTS

Studies with BrS patients undergoing CA for VAs were included. Fourteen studies that involved a total population of 709 BrS patients, with CA performed in 528 of them, were included. CA resulted in the non-inducibility of VAs in 91% (95% CI: 83-99, I2 = 76%) and resolution of type 1 ECG Brugada pattern in 88% (95% CI: 81-96.2, I2 = 91%) of the patients. After a mean follow-up of 30.7 months, 87% (95% CI: 80-94, I2 = 82%) of patients remained free from VAs. The incidence of VAs during follow-up was significantly lower in the ablation cohort in comparison to the group receiving only ICD therapy (OR = 0.03, 95% CI: 0.01-0.12, I2 = 0%).

CONCLUSION

CA shows potential as a therapeutic approach to reduce VAs and improve outcomes in BrS patients. While further research with a long follow-up period is required to confirm these findings, it represents a valuable tool as an add-on intervention to ICD implantation in BrS patients with a high burden of VAs.

Catheter Ablation for Channelopathies: When Is Less More?

Ventricular fibrillation (VF) is a common cause of sudden cardiac death in patients with channelopathies, particularly in the young population. Although pharmacological treatment, cardiac sympathectomy, and implantable cardioverter defibrillators (ICD) have been the mainstay in the management of VF in patients with channelopathies, they are associated with significant adverse effects and complications, leading to poor quality of life. Given these drawbacks, catheter ablation has been proposed as a therapeutic option for patients with channelopathies. Advances in imaging techniques and modern mapping technologies have enabled increased precision in identifying arrhythmia triggers and substrate modification. This has aided our understanding of the underlying pathophysiology of ventricular arrhythmias in channelopathies, highlighting the roles of the Purkinje network and the epicardial right ventricular outflow tract in arrhythmogenesis. This review explores the role of catheter ablation in managing the most common channelopathies (Brugada syndrome, congenital long QT syndrome, short QT syndrome, and catecholaminergic polymorphic ventricular tachycardia). While the initial results for ablation in Brugada syndrome are promising, the long-term efficacy and durability of ablation in different channelopathies require further investigation. Given the genetic and phenotypic heterogeneity of channelopathies, future studies are needed to show whether catheter ablation in patients with channelopathies is associated with a reduction in VF, and psychological distress stemming from recurrent ICD shocks, particularly relative to other available therapeutic options (e.g., quinidine in high-risk Brugada patients).

Future direction of substrate-based catheter ablation in Brugada syndrome and other inherited primary arrhythmia syndromes: Systematic review and meta-analysis

Background

Inherited Primary Arrhythmias Syndromes (IPAS), especially Brugada syndrome (BrS), have been associated with arrhythmogenic substrates that can be targeted through ablation. This meta-analysis evaluated the outcomes of catheter ablation (CA) in different types of IPAS based on procedural guidance and location.

Methods

A systematic search was conducted across multiple databases to identify studies reporting on ventricular arrhythmia (VA) events before and after CA in IPAS, including BrS, Long-QT syndrome (LQTS), Early repolarization syndrome (ERS), and Idiopathic ventricular fibrillation (IVF). The primary outcomes were VA recurrence and VA burden, evaluated through conditional subgroup analysis. Procedural data were collected as secondary outcomes.

Results

A total of 21 studies involving 584 IPAS patients who underwent CA were included. Following a mean follow-up duration of 33.5 months, substrate-based ablation demonstrated efficacy in reducing VA recurrence across all types of IPAS [RR 0.23; 95% CI (0.13-0.39); p < .001; I 2 = 74%]. However, activation guidance ablation was found to be effective only in IVF cases. Although recurrences still occurred, CA was successful in reducing VA burden [MD -4.70; 95% CI (-6.11-(-3.29); p < .001; I 2 = 74%]. The mean size of arrhythmogenic substrate was 15.70 cm2 [95% CI (12.34-19.99 cm2)], predominantly distributed in the epicardial right ventricular outflow tract (RVOT) in BrS cases and LQTS [Proportion 0.99; 95% CI (0.96-1.00) and Proportion 0.82; 95% CI ( 0.59-1.00), respectively].

Conclusion

Substrate-based CA has demonstrated effective prevention of VA and reduction in VA burden in IPAS cases.

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

BACKGROUND

Patients with Brugada syndrome (BrS) may experience recurrent ventricular arrhythmias (VAs). Catheter ablation is becoming an emerging paradigm for treatment of BrS.

OBJECTIVE

To assess the efficacy and safety of catheter ablation in BrS in an updated systematic review.

METHODS

We comprehensively searched the databases of Pubmed/Medline, EMBASE, and Cochrane Central Register of Controlled Trials from inception to 11th of August 2021.

RESULTS

Fifty-six studies involving 388 patients were included. A substrate-based strategy was used in 338 cases (87%), and a strategy of targeting premature ventricular complex (PVCs)/ventricular tachycardias (VTs) that triggered ventricular fibrillation (VF) in 47 cases (12%), with combined abnormal electrogram and PVC/VT ablation in 3 cases (1%). Sodium channel blocker was frequently used to augment the arrhythmogenic substrate in 309/388 cases (80%), which included a variety of agents, of which ajmaline was most commonly used. After ablation procedure, the pooled incidence of non-inducibility of VA was 87.1% (95% confidence interval [CI], 73.4-94.3; I2 = 51%), and acute resolution of type I ECG was seen in 74.5% (95% CI [52.3-88.6]; I2 = 75%). Over a weighted mean follow up of 28 months, 7.6% (95% CI [2.1-24]; I2 = 67%) had recurrence of type I ECG either spontaneously or with drug challenge and 17.6% (95% CI [10.2-28.6]; I2 = 60%) had recurrence of VA.

CONCLUSION

Catheter ablation appears to be an efficacious strategy for elimination of arrhythmias or substrate associated with BrS. Further study is needed to identify which patients stand to benefit, and optimal provocation protocol for identifying ablation targets.

Lights and shadows of subcutaneous implantable cardioverter-defibrillator in Brugada syndrome

Currently the cornerstone of therapy for ventricular arrhythmic complications and sudden cardiac death prevention in Brugada syndrome (BrS) is an implantable cardioverter-defibrillator (ICD). BrS patient population differs from the majority of patients with an ICD implanted for structural heart disease, and as widely known, transvenous ICD (TV-ICD) systems have been associated with high complication rates in patients with BrS. Technological evolution of these devices has certainly reduced complications due to the device itself, but a careful preimplant screening of these patients is still essential. To date, criteria for an adequate screening process to select suitable candidates for a subcutaneous implantable cardioverter-defibrillator (S-ICD) from patients with BrS are sometimes nonstandardized and often lack important precautions that are instead fundamental to select the most suitable type of ICD for these patients. To better select suitable candidates for an S-ICD from patients with BrS, a full screening process should include screening during or immediately after an exercise test and after a drug provocation challenge test. We report an analysis of the "lights and shadows" of S-ICD for a correct use of this device in patients with BrS.