Brugada Pattern Electrocardiogram Associated with Supratherapeutic Phenytoin Levels and the Risk of Sudden Death

Abstract

The emergence of Brugada pattern on electrocardiogram in response to class IA or IC antiarrhythmic agents is widely utilized to diagnose concealed Brugada syndrome and recognized as a risk factor for sudden death. Phenytoin, a class IB antiarrhythmic agent, has not been reported to induce Brugada pattern. We report a patient who presented with Brugada electrocardiogram at supratherapeutic phenytoin level. Considering that patients with syncope may falsely be labeled to have seizures and some epilepsy patients are at increased risk of sudden death, all patients with supratherapeutic phenytoin level should be evaluated with an electrocardiogram for emergence of Brugada pattern.

Effects of Seizures on Cardiac Function

“…Prolonged QT intervals have been reported in recordings of patients who died of SUDEP compared with those of living control patients with epilepsy (Oppenheimer, 1990;Tavernor et al, 1996). Antiepileptic medication such as phenytoin may elicit a previously undiagnosed Brugada syndrome (Al Aloul et al, 2007).…”

Sudden cardiac death: epidemiology and risk factors

“…8,84,85 These conditions are rare in the community; however, QT-interval prolongation and dispersion, which are more common and indicate prolonged repolarization, have also been associated with SCD in the general population. 2,86,87 Individuals with a corrected QT interval of greater than 440 ms have a 2.3-fold higher risk of SCD than those with corrected QT interval of less than 440 ms, independent of age, sex, heart rate, and drug use.…”

“…2,86,87 Individuals with a corrected QT interval of greater than 440 ms have a 2.3-fold higher risk of SCD than those with corrected QT interval of less than 440 ms, independent of age, sex, heart rate, and drug use. 85 Furthermore, those with QT prolongation in the absence of QT prolonging drugs or diabetes have a fivefold increased risk of SCD. 87 …”

Monitoring the safety of antiepileptic medication in a child with Brugada syndrome

“…Calcium channel blockers such as pinacidil and verapamil, amiodarone, vagotonic agonists, α-adrenergic agonists, β-adrenergic antagonists, tricyclic antidepressants, antihistaminics (dimenhydrinate), dextrose and insulin combinations, cocaine, lithium [4]… are known to exacerbate rhythm disturbances in BS. Quite recently BS was documented in a patient on a supratherapeutic dosage of fenytoin (class IB anti-arrhythmic drug) administered for the treatment of his convulsions [5].…”