Low rate of life-threatening events and limitations in predicting
invasive and non-invasive markers of symptoms in a cohort of type 1
Brugada syndrome patients. Data and insights from the GenBra Registry.
Abstract
Background: Brugada syndrome (BrS) has diagnostic challenges and
controversial risk assessment. We aimed to investigate invasive and
non-invasive parameters in symptomatic and asymptomatic patients from a
Brazilian cohort of type-1 BrS. Methods Patients with spontaneous and
drug-induced type-1 BrS were classified in two groups, asymptomatic
(n=116, 84.1%) and symptomatic (n=22, 15.9%, 13 with arrhythmogenic
syncope, 9 with aborted sudden cardiac death). Genetic testing, EPS
parameters, and ECG parameters were analysed. Results: 138 consecutive
patients were eligible, 101 men (73.2%), mean 41.4 years, mostly
probands (79%). Spontaneous pattern, observed in 77.5% of the
patients, was associated to symptoms only if expressed in V1 and V2
standard position (not high precordial leads) (p=0.014). All symptomatic
patients were probands. The presence of RV outflow tract conduction
delay (RVOTcd) signs, positive EPS and SCN5A status was similar between
symptomatic and asymptomatic subjects. During mean 75-month follow-up, 8
patients had appropriate therapies. All had spontaneous type-1 ECG
pattern and 2/8 (25%) were asymptomatic, with positive EPS. The overall
LAE incidence of 1.1%/year dropped to 0.27% in asymptomatic patients.
RVOTcd occurred more frequently in SCN5A carriers (QRS-f 33.3% vs
7.7%, p=0.005; AVR sign 58.3% vs 13.6%, p<0.001; deep S in
lead I 75% vs 48.5%, p=0.025%), as well as longer HV interval (66ms
vs 49ms, p<0.001). Conclusions: Spontaneous type-1 Brugada
pattern in standard leads and proband status were more frequent in
symptomatic subjects. RVOTcd, more common in SCN5A carriers, did not
predict symptoms in BrS patients. EPS exhibited limited prognostic value
for this low risk population.