Long-term tocainide therapy for ventricular arrhythmias.

Area of Science:

• Cardiology
• Pharmacology
• Clinical Electrophysiology

Background:

• Ventricular arrhythmias pose a significant clinical challenge.
• Conventional antiarrhythmic drugs (quinidine, procainamide, propranolol) are often ineffective or poorly tolerated.
• Tocainide, an oral analog of lidocaine, offers a potential alternative for managing refractory arrhythmias.

Purpose of the Study:

• To evaluate the long-term efficacy and safety of tocainide in patients with refractory ventricular arrhythmias.
• To determine the optimal method for assessing long-term antiarrhythmic drug efficacy.

Main Methods:

• A cohort of 17 patients with recurrent or symptomatic ventricular arrhythmias, refractory to other treatments, received tocainide.
• Tocainide dosages ranged from 300 to 700 mg every 8 hours, with plasma concentrations monitored.
• Efficacy was assessed by reduction in arrhythmias, symptomatic control, and long-term follow-up.

Main Results:

• Tocainide controlled arrhythmias in 9 out of 17 patients (53%).
• Therapy was unsuccessful in 8 patients, with 3 deaths during treatment.
• Minor side effects were generally well-tolerated, and 7 patients continued long-term therapy.
• Ambulatory electrocardiographic recordings were crucial for evaluating drug efficacy, especially for asymptomatic arrhythmias.

Conclusions:

• Tocainide demonstrates moderate efficacy in a subset of patients with refractory ventricular arrhythmias.
• Long-term tocainide therapy can be safe and effective, with minor side effects.
• Sequential ambulatory electrocardiographic monitoring is the preferred method for assessing long-term antiarrhythmic drug efficacy.