Flecainide is a class IC antiarrhythmic agent with a controversial role in the treatment of ventricular arrhythmias following
myocardial infarction after the publication of the
Cardiac Arrhythmia Suppression Trial (CAST). To assess its utility in
paroxysmal supraventricular tachycardia (PSVT), we evaluated the electrophysiologic effects and therapeutic efficacy of intravenous
flecainide, administered in a dose of 2 mg per kg
body weight in 26 patients of PSVT, studied by programmed electrical stimulation. The patients' age ranged from 18-49 years (mean: 27 +/- 8) and none had organic
heart disease. The mechanism of PSVT was atrioventricular nodal reentry (AVNRT) with anterograde conduction through slow pathway and retrograde through fast pathway in 14, and atrioventricular reentry (AVRT) utilizing an accessory pathway in 12 patients.
Flecainide was successful in terminating the
tachycardia in all (100%) patients of AVNRT and 11 (92%) patients with AVRT. In both the types, the
tachycardia was terminated by selective block in conduction through the retrograde limb of the reentry circuit. The
drug also produced a complete anterograde block with abolition of preexcitation in 6 out of 8 patients with
WPW syndrome. After the
drug, the
tachycardia was reinducible in one patient of AVNRT and 4 with AVRT. The cycle length of inducible
tachycardia increased from 295 +/- 25 ms to 389 +/- 24.5 ms after
flecainide (p < 0.001). There were no adverse haemodynamic effects of the
drug. Our results, thus, showed that intravenous
flecainide is a highly effective and safe
antiarrhythmic drug for termination of PSVT mediated by atrioventricular nodal and atrioventricular reentry mechanisms without producing any adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS)