Syncope in Brugada syndrome: Prevalence, clinical significance, and clues from history taking to distinguish arrhythmic from nonarrhythmic causes
Introduction
Brugada syndrome (BrS) is characterized by sudden cardiac death at a relatively young age and signature ST-segment elevation in the right precordial electrocardiogram (ECG) leads (type 1 BrS ECG). The associated life-threatening tachyarrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]) may manifest as cardiac arrest or syncope.1
Accordingly, syncope is a sign of increased risk for life-threatening arrhythmias (along with type 1 BrS ECG at baseline, ie, in the absence of provoking drugs), as indicated by studies on risk stratification of BrS.2 Yet, syncope in BrS patients constitutes a diagnostic dilemma. Although syncope in (suspected) BrS patients is often ascribed by default to cardiac arrhythmia in this setting, syncope also may stem from other causes. In the general population, reflex syncope is by far the most frequent cause of syncope, especially in the young, with a cumulative incidence of 40% by the age of 21 years.3 It is difficult to establish whether syncope events in BrS patients are caused by arrhythmia or nonarrhythmic syncope.4 The European Society of Cardiology (ESC) guidelines for syncope are inadequate for risk stratification in relatively young patients with a high risk for ventricular arrhythmias.5 Clearly, it is important to distinguish these types of syncope because the updated consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes6 recommends implantable cardioverter-defibrillator (ICD) placement only in BrS patients with syncope judged likely to be caused by ventricular arrhythmias, given the risk of ICD complications7 and costs.
In an effort to distinguish arrhythmic from nonarrhythmic syncope in BrS patients and to establish the clinical relevance of nonarrhythmic syncope in these patients, we asked the following questions: (1) How many BrS patients sustain arrhythmias and/or nonarrhythmic syncope? (2) Can clinical characteristics be identified to distinguish arrhythmic events from nonarrhythmic syncope in BrS? (3) What is the risk of future arrhythmias in BrS patients with nonarrhythmic syncope?
Section snippets
Study population
We conducted a cohort study at the Academic Medical Center, a large tertiary referral center in the Netherlands, of BrS patients consecutively included between January 1, 2001, and April 1, 2011. BrS was diagnosed when a type 1 BrS ECG was observed in >1 right precordial lead in the presence or absence of a sodium channel-blocking drug (flecainide or ajmaline).1 The institutional review board waived the requirement for informed consent.
Study design
All living patients who had experienced syncope or aborted
Patient characteristics
The total cohort comprised 342 patients. The mean age at diagnosis was 44 ± 14 years, and 205 (60%) were male. About half of the patients (n = 182/342 [53%]) were identified during family screening. Twenty patients (5.8%) initially presented with ACA and 11% (39/343) with syncope. The clinical characteristics of all patients are listed in Table 1.
Sudden cardiac arrest and syncope
By the time of diagnosis, 23 of 342 patients (23/123 families) had experienced ACA (7%; Figure 1), including 20 with an
Main findings
As many as 34% of patients with BrS had a history of ≥1 event of syncope at the time of diagnosis, of whom 57% had suspected nonarrhythmic syncope. Features suggesting ACA were male gender, older age, presence of urinary incontinence, absence of typical prodromes, and, most specifically, absence of typical triggers. The ACA rate during follow-up was 8.7% per year in ACA patients and 0%–0.3% per year in asymptomatic or suspected nonarrhythmic syncope patients. The absence of ACA in patients with
Conclusion
As many as 34% of BrS patients have a lifetime history of syncope at initial presentation, of whom 57% have suspected nonarrhythmic syncope. Clinical features, including absence of prodromes and, particularly, absence of specific triggers, are different between nonarrhythmic syncope and ACA and may be used to distinguish arrhythmic from nonarrhythmic syncope. Therefore, history taking of BrS patients with syncope should be particularly directed to the search for such triggers. The high
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Red Flags in Syncope: Clues for the Diagnosis of Idiopathic Ventricular Fibrillation
2022, American Journal of MedicineBedwetting from the heart: Time for a paradigm shift in the minimal diagnostic evaluation of enuresis
2022, Heart RhythmCitation Excerpt :Urine incontinence often occurs during daytime syncope.10 It is almost 5 times more common during arrhythmogenic syncope than during benign vagal syncope,11 probably because the former leads to deeper and longer cerebral hypoperfusion.10 Indeed, 40% and 45% of daytime syncopal events due to long QT12 and Brugada syndromes11 involve involuntary urination.
Predictive risk models for forecasting arrhythmic outcomes in Brugada syndrome: A focused review
2022, Journal of ElectrocardiologyBrugada Syndrome
2022, JACC: Clinical ElectrophysiologyCitation Excerpt :The annual SAE risk is 2.3%-3.7% for those with cardiogenic syncope and spontaneous ECG, up to 2.0% for those with syncope and SCB-induced BrS, 0.8%-1.2% for those with asymptomatic spontaneous ECG, and ∼0.3% for those with asymptomatic SCB-induced BrS (Figure 5).67,131,136 Importantly, patients with syncope that is not cardiogenic in nature are not at increased risk of SAEs.88 Overall, patient age and sex do not appear to have a significant impact on the risk of SAEs in patients with BrS when considering other factors using multivariate analysis (Table 4).125,126,131,137
Dr. Tan was supported by Grant ZonMW Vici 918.86.616 from the Netherlands Organization for Scientific Research.