Vaping tetrahydrocannabinol unmasks Brugada pattern and induces ventricular fibrillation in Brugada syndrome: a case report.

Background: Fever, alcohol, and sodium channel blockers can unmask Brugada pattern and may also induce arrhythmias in Brugada syndrome. We report a case of unmasked Type-1 Brugada pattern presenting with ventricular fibrillation that was induced by a tetrahydrocannabinol vaping. Case summary: A 48-year-old male with a past medical history of hypertension treated with hydrochlorothiazide and back pain controlled with tetrahydrocannabinol vaping presented with sudden cardiac arrest from ventricular fibrillation, which was terminated with defibrillation. Electrocardiogram after resuscitation showed a new Type-1 Brugada pattern compared to a previous normal baseline electrocardiogram. Echocardiography and coronary angiogram were unremarkable. Complete blood count and chemistries were unremarkable except for mild hypokalaemia (K = 3.3 mmol/L). After correction of the hypokalaemia, the Type-1 Brugada pattern persisted. Urine drug screen was positive for tetrahydrocannabinol (60 ng/mL). Genetic testing was negative for inherited arrhythmic disease and cardiomyopathy gene panels. Discussion: The patient's type-1 Brugada pattern and ventricular fibrillation were likely induced by vaping tetrahydrocannabinol. He underwent secondary prevention with an implantable cardioverter-defibrillator. He abstains from cannabis and Type-1 Brugada pattern is normalized. There was no arrhythmic event at his 18-month follow-up appointment with abstinence from tetrahydrocannabinol.