Twelve-lead ambulatory electrocardiographic monitoring in Brugada syndrome: Potential diagnostic and prognostic implications.

Background: Patients with Brugada syndrome (BrS) are diagnosed and risk stratified on the basis of a spontaneous or drug-induced type 1 electrocardiographic (ECG) pattern, often at single time points not accounting for variation throughout the day.

Objectives: The purpose of this study was to prospectively assess the overall burden of type 1 Brugada ECG changes using 12-lead 24-hour Holter monitoring and evaluate association with cardiac events.

Methods: From July 1, 2013 to December 31, 2015, patients with BrS were recruited from 3 Australian centers and the Australian Genetic Heart Disease Registry. All patients underwent clinical review, baseline ECG, and 12-lead 24-hour Holter assessment with precordial leads placed in the left and right second, third, and fourth intercostal spaces. The frequency, temporal, and spatial burden of type 1 BrS ECG pattern were analyzed and assessed for association with cardiac events.

Results: A total of 54 patients with BrS were recruited (n=44, 81% men; mean age 44 ± 13 years); the mean follow-up was 2.3 ± 2.5 years. Eleven of 32 patients (34%) initially classified as "drug-induced BrS" demonstrated a spontaneous type 1 pattern at least once over 24 hours. Patients with cardiac events had a significantly higher temporal burden of type 1 ST-segment elevation in the 24-hour monitoring period (total area under the curve 21% vs 15%; P = .008), being most pronounced between the hours of 1600 and 2400 (P = .027).

Conclusion: Patients with BrS traditionally classified as drug-induced can exhibit spontaneous ECG changes with longer-term monitoring, particularly in the evening. Temporal burden on 12-lead Holter monitor was associated with cardiac events. Ambulatory 12-lead ECG monitoring may have potential utility in the diagnosis and risk stratification of patients with BrS.