Encainide for treatment of atrioventricular reciprocating tachycardia in the Wolff-Parkinson-White syndrome.

Abstract

Oral encainide, varying from 75 to 300 mg/day (mean 174 mg/day), was administered to 52 patients with drug-resistant atrioventricular reciprocating tachycardia (AVRT) associated with the Wolff-Parkinson-White syndrome. Electrophysiologic studies were performed before and during drug treatment. Encainide resulted in anterograde accessory pathway block in 15 of 37 (41%) and retrograde accessory pathway block in 11 of 46 (24%) patients. In patients with residual accessory pathway conduction, encainide significantly prolonged the shortest pacing cycle length maintaining anterograde (261 +/- 26 to 404 +/- 85 ms) and retrograde (279 +/- 46 to 436 +/- 87 ms) accessory pathway conduction, as well as the anterograde accessory pathway effective refractory period (271 +/- 32 to 329 +/- 73 ms). AVRT could not be induced during encainide therapy in 20 of 49 patients (41%). In the remaining patients, AVRT cycle length increased (319 +/- 44 to 426 +/- 90 ms, p less than 0.001) due to prolongation of HV and ventriculoatrial intervals. During follow-up (mean 38.5 months), 30 patients continued to take the drug and 7 patients with favorable drug response subsequently elected to undergo surgical accessory pathway ablation (71% overall favorable response). Encainide was ineffective in 11 patients, was discontinued because of drug intolerance in 2 patients and exacerbated ventricular tachycardia in 2 patients. Lack of AVRT inducibility at encainide electrophysiologic study did not always predict recurrence-free follow-up. Encainide is an effective and well-tolerated drug to prevent recurrence of AVRT in patients with Wolff-Parkinson-White syndrome.

• Authors: W M Miles, D P Zipes, R L Rinkenberger, M L Markel, E N Prystowsky, A H Dougherty, J J Heger, G V Naccarelli
• Journal: The American journal of cardiology (Am J Cardiol) Vol. 62 Issue 19 Pg. 20L-25L (Dec 20 1988) ISSN: 0002-9149 [Print] United States
• PMID: 3144163 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Anilides
• Anti-Arrhythmia Agents
• Encainide

Topics

• Administration, Oral
• Adolescent
• Adult
• Aged
• Anilides (pharmacology, therapeutic use)
• Anti-Arrhythmia Agents (pharmacology, therapeutic use)
• Electrophysiology
• Encainide
• Female
• Heart Conduction System (drug effects, physiopathology)
• Humans
• Male
• Middle Aged
• Tachycardia, Supraventricular (drug therapy, physiopathology)
• Wolff-Parkinson-White Syndrome (drug therapy, physiopathology)