Low Prevalence of Risk Markers in Cases of Sudden Death Due to Brugada Syndrome: Relevance to Risk Stratification in Brugada Syndrome

Abstract

The objective of this study was to determine the prevalence of conventional risk factors in sudden arrhythmic death syndrome (SADS) probands with Brugada syndrome (BrS). Patients with BrS and previous aborted sudden cardiac death (SCD) are at high risk of recurrent events. Other universally accepted clinical features associated with higher risk include unheralded syncope and the presence of a spontaneous type 1 electrocardiogram (ECG). We analyzed reported symptoms and reviewed ECGs from SADS probands with familial diagnoses of BrS, established by cardiological evaluation, including ECG, 2-dimensional echocardiography, Holter monitoring, exercise tolerance testing, and ajmaline provocation. These cases underwent familial evaluation between 2003 and 2010. A total of 49 consecutive families with a confirmed SADS death and a diagnosis of BrS were evaluated, comprising assessment of 202 family members in total. One family had 2 members with SADS, resulting in a total of 50 probands included. Mean age of death of probands was 29.1 ± 10.6 years, with 41 males (82%) (p < 0.05). Antemortem ECGs were available for 5 SADS probands, 1 of which demonstrated a spontaneous type 1 pattern. In 45 probands, symptoms before death were reported reliably by family members. Of these, 9 (20%) had experienced at least 1 syncopal episode before the fatal event. Importantly, 68% of probands would not have fulfilled any current criteria for consideration of implantable cardioverter-defibrillator. The "low-risk" asymptomatic BrS group comprises the majority of SCD in this cohort. Current risk stratification would appear to be inadequate, and new markers of risk are vital.