Implantable loop recorders in patients with Brugada syndrome: the importance of a correct patient stratification

This commentary refers to ‘Implantable loop recorders in patients with Brugada syndrome: the BruLoop study’, by M. Bergonti et al., https://doi.org/10.1093/eurheartj/ehae133.

We have read with interest the article recently published by Bergonti et al.¹ entitled ‘implantable loop recorders in patients with Brugada syndrome: the BruLoop study’. A total of 370 patients with Brugada syndrome (BrS) with an implantable loop recorder (ILR) were followed with continuous rhythm monitoring for a median follow-up of 3 years. For the authors, ILR detects arrhythmic events in nearly 30% of symptomatic BrS patients, leading to appropriate therapy in 70% of them. The most commonly detected arrhythmias are atrial arrhythmias and bradyarrhythmias, while ventricular arrhythmias are detected only in 7% of cases.

In light of the conclusions of the authors, it would be interesting to know which cluster of BrS patients they monitored: low or high-risk patients, with spontaneous or induced patterns, implanted in primary or secondary prevention?, and if everyone was indiscriminately placed in a single assessment group or if there are differences in the various risk subgroups.

In my opinion, the attention in not generalizing the obtained data to all subgroups of BrS patients is crucial; for example, it is already known that BrS patients stratified as low arrhythmic risk profile have a low probability of major ventricular arrhythmic events. For these reasons, an accurate and multiparametric stratification of patients remains crucial and essential.²

From literature data, we know that late ventricular arrhythmic events during follow-up are significantly associated with a history of atrial arrhythmias and conduction abnormalities detected at baseline clinical evaluation (first-degree AV block and S-wave in lead I). For example, the prognostic value of S-wave in lead I as predictor of life-threatening ventricular arrhythmias was strengthened in a more recent study by Giustetto et al.³ extending it to patients with drug-induced Type 1 ECG and patients with previous cardiac arrest.

How can the authors justify this diversity of literature evidences compared to their study, and which pragmatic approach derives from this in the daily management of such patients?

In light of the most recent guidelines, the implantation of an ILR in patients with BrS does not find a transversal agreement. It finds the diagnostic field only in low-risk patients with dubious symptoms, recognizing that the evidence to support this recommendation is modest and no long-term follow-up data are available, and the decisions regarding reimplantation of a second or third ILR in these patients are not addressed. Here is the reason why it does not fall within the diagnostic and therapeutic pathway recommended by the latest European and American guidelines.^4,5

In the study by Bergonti et al., patients if only carriers of an ILR rather than an implantable cardioverter defibrillator, it is assumed that they were considered at low ventricular arrhythmic risk, and therefore, the monitoring data found by the authors are unchanged with what is known up to now about the ventricular arrhythmic risk of this group of patients; furthermore the follow-up of the study appears to be too short for this type of patients (median follow-up of 3 years).

Considering the importance of a correct stratification of BrS patients, and the consequent correlations with the appropriate therapeutic indications, in my opinion any new data can lead to a better daily clinical practice and, therefore, should be carefully considered and be as specific as possible.

Declarations

Disclosure of Interest

All authors declare no disclosure of interest for this contribution.

References