Mexiletine for recurring ventricular arrhythmias: assessment by long-term electrocardiographic recordings and...

Mexiletine, an oral lidocaine-like drug, was initially thought to be effective treatment for recurring ventricular arrhythmias. Recent work has cast doubt on its efficacy. We administered mexiletine to 32 patients with chronically recurring ventricular arrhythmias. In 22 patients with no history of syncope or documented sustained ventricular arrhythmia (group 1), mexiletine was effective in only 27% (six patients) as assessed by 24-hour ambulatory ECG recordings before and during mexiletine treatment. Ten other patients had a history of syncope or documented sustained ventricular tachycardia or ventricular fibrillation. Only 10% (one patient) responded to mexiletine based on sequential electrophysiologic studies with programmed ventricular stimulation. Four of the seven patients responding to mexiletine had not received prior antiarrhythmic therapy. We conclude that mexiletine has limited efficacy in the treatment of recurring drug-refractory ventricular arrhythmias.