Treatment of ectopic atrial arrhythmias and premature atrial complexes in adults with encainide

Area of Science:

• Cardiology
• Clinical Electrophysiology

Background:

• Limited research exists on encainide's efficacy for primary atrial tachycardias and premature atrial contractions (PACs).
• Patients studied exhibited high resistance to previous antiarrhythmic therapies.

Purpose of the Study:

• To evaluate the antiarrhythmic effects of encainide in patients with primary atrial tachycardias and symptomatic PACs.
• To assess encainide's effectiveness in drug-resistant cases.

Main Methods:

• Systematic review of 11 patients with primary atrial tachycardia and 10 with symptomatic PACs.
• Analysis of intravenous and oral encainide administration, dosages, and treatment durations.
• Evaluation of Holter recordings for PAC reduction.

Main Results:

• Intravenous encainide terminated primary atrial tachycardia in 4/4 patients.
• Oral encainide was effective/partially effective in 6/10 patients with atrial tachycardia (average 2.9 years, 156 mg/day).
• Encainide showed effectiveness in 8/10 (IV) and 6/9 (oral) patients with PACs, reducing median PACs from 1,139/hour to 166/hour (p=0.001).

Conclusions:

• Encainide demonstrates significant efficacy in treating drug-resistant primary atrial tachycardias and symptomatic PACs.
• The drug appears to act by suppressing ectopic pacemaker activity.
• Encainide is a viable treatment option with modest adverse effects for these specific arrhythmias.