ClinicalSudden DeathRole of subcutaneous implantable loop recorder for the diagnosis of arrhythmias in Brugada syndrome: A United Kingdom single-center experience
Graphical abstract
Introduction
Brugada syndrome (BrS) is characterized by “coved” ST segment elevation ≥2 mm in the right precordial electrocardiographic (ECG) leads (type 1 pattern) and increased risk of ventricular arrhythmias (VAs) and sudden cardiac death (SCD).1,2 The incidence of life-threatening VAs in previously asymptomatic subjects with BrS is estimated at 0.3% to 1% per year.3,4 The only proven strategy for prevention of SCD is the implantable-cardioverter defibrillator (ICD), which is recommended in patients with previous aborted cardiac arrest/documented VAs and can be useful in patients with previous arrhythmic syncope and a spontaneous type 1 pattern.1,2 Several other clinical, ECG, and invasive risk factors have been proposed in subjects without documented VAs,5 but risk stratification remains challenging. Subjects with BrS often suffer from neurocardiogenic or unexplained syncopal episodes as well as palpitations secondary to paroxysmal atrial arrhythmias (atrial fibrillation [AF], atrial tachycardia [AT], or atrioventricular nodal reentrant tachycardia [AVNRT]). These have not been associated consistently with VAs during follow-up.6, 7, 8, 9, 10
Implantable loop recorders (ILRs) are indicated for investigation of syncope or palpitations in high-risk patients in whom comprehensive evaluation has not demonstrated a cause or led to treatment.11 ILRs may have a role in correlating symptoms and suspected VA in BrS patients,2,12 preventing unnecessary ICD implantation, and offering reassurance. However, the experience with ILRs in BrS is limited.8,13,14 This study sought to evaluate the indications for ILR implantation and the yield of ILR-guided diagnosis in a large single-center cohort of BrS patients.
Section snippets
Study population
Consecutive adult patients with a diagnosis of BrS were included from 2008 to June 2020. Subjects with significant coronary or cardiomyopathic disease or metabolic abnormality at the time of type 1 ECG pattern were excluded. The study was approved by the regional ethics committee and Trust R&D. All patients provided informed consent for inclusion in the study.
Data collection
Retrospective demographic and clinical data, including symptoms, results of cardiac investigations and genetic tests, and details on
Clinical population
Four hundred fifteen subjects were included in the study. All subjects underwent investigations to exclude BrS phenocopies.17 A total of 50 patients (12%) received an ILR. Twenty-nine (58%) were male, and 33 were Caucasian (66%). Twenty-nine subjects (58%) had a probable/definite diagnosis of BrS based on the Shanghai score. Mean age at ILR implantation was 44 ± 15 years. Thirty-one subjects (62%) previously had experienced a syncopal or presyncopal episode. In 18 subjects the syncope was
Comparison between subjects receiving ILR, ICD,or no device therapy
We compared the demographic, clinical, ECG, and genetic characteristics of subjects without previous aborted cardiac arrest who received an ILR, an ICD, or no device (Table 1). Those who received an ICD for primary prevention were more likely to display a spontaneous type 1 pattern compared to those receiving an ILR, whereas there were no differences with regard to gender, age at implantation, Shanghai score, genetic background, or inducibility of VF at EPS between the 2 groups. Subjects who
Discussion
To our knowledge, the present study details the largest experience with the use of ILRs in patients with BrS reported to date. The main finding is that ILR monitoring detected an actionable arrhythmia in 22% of subjects considered to be at insufficient risk for life-threatening VAs to warrant immediate ICD implantation. Diagnoses were made in 4 of 7 of subjects who suffered a recurrence of syncope or presyncope and in 5 of 10 subjects with symptomatic palpitations. Paroxysmal sinus node or AV
Conclusion
Implantable cardiac monitor devices are useful to guide diagnosis in symptomatic BrS subjects deemed at insufficient risk for SCD to require immediate ICD implantation. Recurrent syncope, including unexplained episodes in subjects without spontaneous type 1 pattern and with negative EPS, often is secondary to conduction and sinus nodal dysfunction.
Acknowledgment
The authors thank Miss Katie Frampton for her support in the realization of this work.
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Cited by (18)
Implantable loop recorder in Brugada syndrome: Insights from a single-center experience
2024, IJC Heart and VasculatureOutcome of patients with early repolarization pattern and syncope
2022, Heart RhythmCitation Excerpt :Of note, the incidence of bradycardias was higher than the incidence of ventricular tachyarrhythmias. Similarly, continuous ILR monitoring revealed that bradycardias were detected more frequently than ventricular arrhythmias in patients with Brugada syndrome.14,15 This is consistent with previous studies that used ILRs for the diagnosis of unexplained syncope, in which the events were caused by bradycardias in the majority of patients.16
Brugada Syndrome
2022, JACC: Clinical ElectrophysiologyCitation Excerpt :Nevertheless, the authors would recommend a primary prevention ICD for patients with BrS (either spontaneous or provoked) and a history of cardiogenic syncope. In patients with a spontaneous type 1 ECG and vasovagal syncope or syncope of uncertain origin, an implanted loop recorder may be considered, recognizing that the evidence to support this recommendation is modest.193-195 In patients with a spontaneous type 1 ECG who are asymptomatic, we would advocate for close follow-up due to the current limitations of other risk stratification methods, generally avoiding a primary prevention ICD unless other markers of risk are considered relevant in consultation with an expert.
Implantable loop recorders in Brugada syndrome: An ally?
2022, Heart RhythmCan an implantable loop recorder improve risk stratification and appropriate management in Brugada syndrome?
2024, European Heart Journal
Funding Sources: Dr Scrocco is supported by the Robert Lancaster Memorial Fund sponsored by McColl’s Retail Group Ltd and by the British Heart Foundation (BHF Project Grant PG/15/107/31908). Disclosures: The authors have no conflicts of interest to disclose.