Effects of low-dose quinidine on ventricular tachyarrhythmias in patients with Brugada syndrome: low-dose quinidine therapy as an adjunctive treatment

Journal of Cardiovascular Pharmacology
Yuka MizusawaMasayasu Hiraoka

Abstract

Quinidine is suggested as an effective agent to suppress ventricular fibrillation (VF) in the Brugada syndrome by inhibiting transient outward K(+) current (Ito) leading to the reduction and abbreviation of the disparity of repolarization in the right ventricular outflow region and ST segment elevation in the right precordial leads of electrocardiogram. We sought to assess the efficacy of low-dose (300-600 mg) quinidine sulfate on the prevention of ventricular fibrillation induction by programmed electrical stimulation (PES) and spontaneous ventricular fibrillation episodes during the subsequent follow-up period. Electrophysiologic study was performed in 14 patients with the Brugada syndrome (14 men, mean age 50 +/- 11 years, range 32-75) before and during the treatment with low-dose quinidine and evaluated the efficacy of the drug therapy. Ventricular fibrillation was induced in all the patients by programmed electrical stimulation at baseline. After oral quinidine administration (300 mg or 600 mg/d), programmed electrical stimulation was repeated. Ventricular fibrillation induction was prevented in 6 of 14 patients (44%). Serum quinidine concentration was higher in the patients with suppressed VF induction than those without ...Continue Reading

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