Effects of Electrophysiologic‐Guided Therapy with Class IA Antiarrhythmic Drugs on the Long‐Term Outcome of Patients with Idiopathic Ventricular Fibrillation with or without the Brugada Syndrome

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Abstract
Electrophysiologic Drug Testing in Idiopathic VF. Introduction: Implantation of a implantable cardioverter defibrillator (ICD) is viewed universally as the “gold standard” therapy for patients with idiopathic ventricular fibrillation (VF). We sought to study the long‐term value of electrophysiologic (EP)‐guided therapy with Class IA antiarrhythmic drugs in patients with idiopathic VF with or without the Brugada syndrome. Methods and Results: We performed EP studies in 34 consecutive patients who had idiopathic VF with (n = 5) or without (n = 29) the Brugada syndrome. All patients with inducible sustained polymorphic ventricular tachycardia (SPVT) or VF underwent repeated EP evaluation after oral administration of a Class IA antiarrhythmic drug (mainly quinidine). Patients rendered noninducible received this therapy on a long‐term basis. SPVTA/VF were induced in 27 (79.4%) patients at baseline studies. Class IA drugs effectively prevented induction of SPVTA'F in 26 (96%) patients. Of the 23 patients treated with these medications, no patient died or had a sustained ventricular arrhythmia during a mean follow‐up period of 9.1 ± 5.6 years (7 to 20 years in 15 patients). Two deaths occurred in patients without inducible SPVTA'F at baseline studies who had been treated empirically. Conclusion: Our results suggest that EP‐guided therapy with Class IA agents is a reasonable, safe, and effective approach for the long‐term management of patients with idiopathic VF. A randomized prospective study of EP‐guided Class IA therapy in patients with ICDs seems warranted.