title: Suppression of ventricular premature contractions continues after the washout of antiarrhythmic drugs.
abstract: The effects of the washout of antiarrhythmic drugs on the frequency of ventricular premature contraction (VPC) were investigated in 64 patients (VPCs > 2000/day). Included were patients on mexiletine (300-600 mg/day; 23 patients), disopyramide (300-600 mg/day; 19 patients) and atenolol (50 mg/day; 22 patients). Holter monitoring was repeated before, during and after the treatment with the above 3 drugs and the efficacies of the drugs were evaluated based on the spontaneous variability before the treatment. VPC reduction exceeding the calculated spontaneous variability during drugs therapy (drug-responders) and after the washout of the drugs (wash-responders) was noted in 17 (63%) and 3 (13%) of the mexiletine group; 11 (58%) and 5 (26%) of the disopyramide group; and 13 (59%) and 8 (36%) of the atenolol group, respectively. For the entire group of 64 patients, wash-responders were noted significantly (p < 0.05) more among drug-responders (14 of 41 patients; 34%) than drug-nonresponders (2 of 23 patients; 9%). Therefore, the antiarrhythmic effects of drugs observed during drugs therapy seem to continue even after the discontinuation of antiarrhythmic drugs in 34% of patients those whose VPC reduction exceeded the spontaneous variability (drug-responders).
authors.affiliation: Department of Internal Medicine, Oita Medical University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Saikawa
authors.forename: M
authors.initials: M
authors.lastname: Ito
authors.forename: M
authors.initials: M
authors.lastname: Nakagawa
authors.forename: N
authors.initials: N
authors.lastname: Shimoyama
authors.forename: M
authors.initials: M
authors.lastname: Hara
authors.forename: H
authors.initials: H
authors.lastname: Yonemochi
authors.forename: T
authors.initials: T
authors.lastname: Maeda
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: R
authors.initials: R
authors.lastname: Takaki
authors.forename: M
authors.initials: M
authors.lastname: Arita
mesh_terms: D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000493:pharmacokinetics* / Q000494:pharmacology; D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D001262:Atenolol / Q000493:pharmacokinetics / Q000494:pharmacology; D004206:Disopyramide / Q000493:pharmacokinetics / Q000494:pharmacology; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D008297:Male; D008801:Mexiletine / Q000493:pharmacokinetics / Q000494:pharmacology; D008875:Middle Aged
chemical_list: D000889:Anti-Arrhythmia Agents; D008801:Mexiletine; D001262:Atenolol; D004206:Disopyramide