Pharmacological Provocation Tests With Sodium Channel Blockers in Suspected Brugada Syndrome: Are Current Guidelines Missing Cases?

Brugada Syndrome (BrS) is a genetic condition that increases the risk of sudden cardiac death. Diagnosis relies on the presence of a type 1 Brugada electrocardiogram (ECG) pattern, which may be intermittent. In patients without symptoms or family history, the value of pharmacological provocation with sodium channel blockers (SCB) remains uncertain. The aim of this study was to evaluate the follow-up of patients with a positive ajmaline test who, according to current recommendations, would not have been eligible for undergoing the test. A retrospective study analyzed patients who underwent SCB provocation testing for suspected BrS based on ECG abnormalities, excluding those with prior cardiac arrest, syncope, nocturnal agonal respiration, or family history of BrS or sudden unexplained death. Patients with an induced type 1 Brugada pattern were further evaluated regarding spontaneous type 1 Brugada pattern, pathogenic or probably pathogenic genetic variants or, in the context of family screening, other family members with a Brugada pattern. Among 58 SCB provocation tests performed in patients with suspected Brugada pattern and no family history or relevant symptoms, 50% had a type 1 pattern in the treadmill exercise ECG, 36.7% had other family members with a BrS diagnosis, 23.3% had a spontaneous type 1 pattern in 12-lead ECG during follow-up, 20% had a type 1 pattern in 24-hour modified Holter and 13.3% had a positive genetic test for a pathogenic or probably pathogenic genetic variant. In conclusion, the current guidelines may be excessively restrictive regarding the diagnosis of BrS and, while leading to fewer false positives, may exclude patients with a true BrS diagnosis.