[Acute and long-term antiarrhythmia effect of encainide in chronic atrial extrasystole].
The antiarrhythmic effects of Encainide in acute intravenous and long-term oral therapy were investigated in 10 patients suffering from chronic atrial ectopic beats previously non-responsive to conventional therapy. The efficacy of Encainide was assessed by 24-hour ECG monitoring during the acute i.v. application and in 4 week intervals over a period of 4 to 6 months. Plasma concentrations of Encainide and the O-demethyl- (ODE) and 3-methoxy-O-demethyl metabolites (3-MODE) were determined after i.v. administration and during oral therapy. A significant reduction of arrhythmias by 76% was found after 1.0 mg/kg Encainide given intravenously. Atrial ectopic beats with bundle branch block QRS-morphology were reduced by more than 90% after only 0.5 mg/kg. During long-term oral therapy 6 of the 9 patients were treated successfully. Following i.v. administration Encainide-plasma concentrations rapidly decreased with a half life of approximately 75 min in the final distribution phase. During oral therapy Encainide levels were not detectable under steady state conditions 4 to 6 hours after the last dose, or they were only minimal, but the average concentrations of ODE and 3-MODE were 71.3 +/- 21.3 and 75.6 +/- 13.5 ng/ml. Encainide increased PR interval and QRS duration significantly. QT-interval changed as a result of the QRS-prolongation. Encainide was well tolerated during acute and chronic therapy. No severe side effects were seen, except in one case, in which dose reduction by 50% was necessary because of blurred vision.(ABSTRACT TRUNCATED AT 250 WORDS)
Thale
J
J
Klein
H
H
Shanks
R G
RG
Bender
F
F
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000813:Anilides / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D005117:Cardiac Complexes, Premature / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D016700:Encainide; D005260:Female; D006207:Half-Life; D006325:Heart Atria / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007263:Infusions, Parenteral; D008134:Long-Term Care; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged
D000813:Anilides; D000889:Anti-Arrhythmia Agents; D016700:Encainide
Antiarrhythmische Akut- und Langzeitwirkung von Encainid bei chronischer Vorhofextrasystolie.