Sodium-channel blocker challenge unmasks Brugada syndrome in a 54-year-old male presenting with recurrent syncope and chronic cannabis use

Figures

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  Figure 1. Initial electrocardiogram showing a saddleback ST-segment elevation in V2, a J-point elevation of ≥2 mm with an ST-segment elevation of ≥1 mm, consistent with a type 2 Brugada pattern. Initial 12-lead electrocardiogram on presentation, demonstrating normal sinus rhythm with a saddleback ST-segment morphology in V1–V2 (J-point elevation ≥2 mm; ST-segment elevation ≥1 mm), consistent with a nondiagnostic type 2 Brugada pattern.

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  Figure 2. Repeat electrocardiogram showing more prominent saddleback morphology in V2. Repeat 12-lead electrocardiogram several hours after admission, showing accentuation of the saddleback morphology in V2.

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  Figure 3. Electrocardiogram after flecainide challenge demonstrating conversion to a diagnostic type 1 coved ST-segment elevation of ≥2 mm followed by a negative T wave in V2 and V3, confirming Brugada syndrome. 12-lead electrocardiogram during intravenous flecainide challenge (2 mg/kg over 10 minutes), demonstrating conversion to a diagnostic type 1 coved ST-segment elevation of ≥2 mm followed by an inverted T wave in V1–V3, confirming the diagnosis of Brugada syndrome.

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  Figure 4. Fourth electrocardiogram showing return to normal sinus rhythm. 12-lead electrocardiogram several hours after drug clearance, demonstrating return to baseline sinus rhythm with resolution of the type 1 pattern.

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  Figure 5. Visual summary of events that occurred during hospitalization. A 54-year-old man with chronic daily cannabis use and a concurrent febrile illness presented with recurrent syncope and a nondiagnostic type 2 “saddleback” ECG pattern with an otherwise unremarkable cardiac workup. IV flecainide challenge (2 mg/kg over 10 minutes) converted the tracing to a diagnostic type 1 “coved” pattern in V1–V3, confirming Brugada syndrome. After declining a primary-prevention ICD, the patient received an ICM paired with trigger avoidance and cascade family screening as a guideline-supported interim strategy. BNP = B-type natriuretic peptide; CAD-RADS = Coronary Artery Disease Reporting and Data System; CCTA = coronary computed tomography angiography; ECG = electrocardiogram; ICD = implantable cardioverter-defibrillator; ICM = implantable cardiac monitor; IV = intravenous; URI = upper respiratory infection.