Added value of 12-lead 24-hour ambulatory ECG monitoring in the identification of a spontaneous type 1 Brugada pattern and its prognostic role. A sub-study of the BHF RASE Brugada project

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: Foundation. Main funding source(s): British Heart Foundation BACKGROUND: A spontaneous type 1 Brugada (spT1-BrS) pattern is a recognised marker of arrhythmic risk. However, its fluctuations may underestimate the risk in subjects with concealed T1-BrS at presentation. AIM: To investigate the yield of repeat resting and high-lead 12-lead ECG and the additional role of 12-lead 24-hour Holter monitoring with leads V1 and V2 in standard and high precordial ECG positions (12-HPL Holter), and evaluate the prognostic role of spT1-BrS in a large, single-centre, cohort of BrS patients. METHODS: Three-hundred and eighty-one subjects with BrS enrolled in our Registry from 2008 to December 2021 and with at least 3 months follow-up data were included in this study. Seventy-seven had spT1-BrS pattern at presentation (Group 1), and 304 did not (Group 2). All received lifestyle recommendations and had regular follow-up appointments with 12-lead ECG; the majority of them were also screened with 12-HPL Holter. Medical notes and tracings were reviewed to identify a dynamic spT1-BrS and events at f-up (SCD/appropriate ICD shock). RESULTS: The mean age at presentation was 44±15 years; 52% of participants were males. All had at least 2 resting ECGs recorded; in 281 subjects at least one 12-HPL Holter was available (total 643, median 2, range 1-8). Over a median follow-up of 66 months (IQR 75), 37 subjects in Group 2 showed a spT1-BrS at least once: 10 during a repeat resting ECG, 2 during/after exercise tolerance test, 25 at 12-HPL Holter. The average time at spT1 appearance during follow-up was 23 months (range 1- 225). Those with a newly detected spT1-BrS were more frequently males and less likely to have a familial history of sudden cardiac death (Table 1). Excluding subjects with previous aCA/documented VT, 6 events occurred at f-up, all in subjects with spT1 (Figure 1). Univariate models showed that the presence of a spT1-BrS pattern was consistently associated with increased risk of events (at presentation: HR 10, 95% C.I. 1.8-54; at follow-up: HR 5.3, 95% C.I. 1.6-17). CONCLUSIONS: A spontaneous T1-BrS can be detected in up to 12% of subjects with concealed BrS at presentation using 12-HPL Holter monitoring. Its presence is consistently associated with arrhythmic risk at f-up up, regardless of the time at detection. Prolonged ambulatory ECG monitoring is fundamental for risk stratification in this population. [Figure: see text] [Figure: see text]