title: Long-term antiarrhythmic therapy with acetylprocainamide.
abstract: Nineteen patients whose arrhythmias were initially suppressed with acetylprocainamide underwent long-term treatment with this drug. Eleven patients were still taking the drug at the end of 12 months. Drug withdrawal with substitution of a placebo caused an increase in ventricular premature beats. Thus, suppression of ventricular premature beats persisted for 1 year. The eight withdrawals from the study were due to death during the year (n = 6) or recurrence of arrhythmias. The deaths occurred in patients who were in New York Heart Association functional class II (one patient), III (three patients) and IV (two patients). Ventricular performance, assessed from systolic time intervals, improved with drug therapy and declined during drug withdrawal. Symptomatic effects were common, with seven patients requiring a reduction in dosage or discontinuation of therapy. Three patients treated for 3 years continued to show drug suppression of ventricular premature beats compared with the level during placebo substitution. Small amounts of procainamide were present in all patients because of in vivo deacetylation of acetylprocainamide. Many patients with good initial responses to this drug had recurrent arrhythmias during long-term therapy. For this reason, the usefulness of acetylprocainamide as an antiarrhythmic drug appears to be limited.
mesh_terms: D000120:Acecainide / Q000009:adverse effects / Q000627:therapeutic use*; D000107:Acetylation; D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D001172:Arthritis, Rheumatoid / Q000139:chemically induced; D002561:Cerebrovascular Disorders / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D005260:Female; D006333:Heart Failure / Q000401:mortality; D006801:Humans; D008134:Long-Term Care; D008297:Male; D008875:Middle Aged; D011342:Procainamide / Q000009:adverse effects / Q000031:analogs & derivatives*; D013599:Systole / Q000187:drug effects; D013610:Tachycardia / Q000188:drug therapy; D014693:Ventricular Fibrillation / Q000401:mortality
chemical_list: D000889:Anti-Arrhythmia Agents; D000120:Acecainide; D011342:Procainamide