Tocainide for drug-resistant sustained ventricular tachyarrhythmias
GC Adhar,
CD Swerdlow,
BL Lance,
D Clay,
GH Bardy,
and
HL Greene
Department of Medicine, University of Washington, Harborview Medical Center, Seattle 98104.
Eighty-two patients with drug-resistant ventricular tachycardia or fibrillation were treated with oral tocainide. Treatment in 54 patients, all with inducible ventricular tachycardia or fibrillation at baseline electrophysiologic testing, was based on the results of invasive electrophysiologic testing. Twenty-eight additional patients with frequent spontaneous ventricular tachycardia or no inducible arrhythmia during electrophysiologic testing were treated on the basis of the findings of electrocardiographic (ECG) Holter monitoring. Tocainide was effective in 7 (13%) and partially effective in 5 (8%) of the 54 patients in the electrophysiologic study group and was effective in 17 (61%) of the 28 patients in the ECG monitoring group. History of previous myocardial infarction and failure of response to lidocaine correlated with failure to respond to tocainide. Side effects were common both during initial therapy and during long-term treatment and necessitated discontinuation of tocainide therapy in 17% of the patients. At a mean follow-up period of 14 months, 13 patients are still receiving tocainide and are arrhythmia-free. In conclusion, the usefulness of oral tocainide in the management of drug-refractory sustained ventricular tachycardia or fibrillation is limited because of its low effectiveness and frequent side effects.
