title: The usefulness of Holter monitoring in the evaluation of antiarrhythmic drug efficacy for tachycardia.
abstract: Using Holter monitoring tachycardia was found in 145 out of 2058 patients suffering from various underlying diseases. Three thousand seven hundred and forty monitorings were performed. The mean age of patients was 54.5 years with a range of 19 to 83 years. The observed tachycardia was classified into three types: tachycardia with short duration, tachycardia with long duration and tachycardia with complex form. The attacks of tachycardia were more frequently observed during periods of physical activity than during sleeping periods. The relationship of the number of tachycardia with short duration between 24-hour Holter monitorings was examined in order to establish day to day variability of the attacks. The 95% confidence interval about the resultant regression line was calculated and the percent reduction required for the evaluation of drug efficacy to avoid the chances of interference of spontaneous variation was found to be about 44.0, 55.0 and 82% when the total number of attacks during a 24-hour period were 50, 100 and 1,000, respectively. Holter monitoring showed higher positive results as compared to exercise testing for detection of tachycardia. Higher correlation coefficients between numbers of premature ventricular contractions (PVCs) and the plasma concentrations of procainamide or N-acetylprocainamide were observed in 3 or more successive PVCs than in individually occurring PVCs. Using repeated 24-hour Holter monitorings a significant reduction in the number of tachycardia was observed when the therapeutic concentration was reached after the combined or single administration of the drug. These results suggest that repeated Holter monitorings, exercise testing and determination of plasma level of the drug may be useful for the evaluation of antiarrhythmic drug efficacy for tachycardia.
mesh_terms: D000328:Adult; D000368:Aged; D000788:Angina Pectoris, Variant / Q000150:complications; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004110:Diltiazem / Q000627:therapeutic use; D004206:Disopyramide / Q000627:therapeutic use; D005260:Female; D006330:Heart Defects, Congenital / Q000150:complications; D006349:Heart Valve Diseases / Q000150:complications; D006801:Humans; D008297:Male; D008801:Mexiletine / Q000627:therapeutic use; D008875:Middle Aged; D008991:Monitoring, Physiologic; D009203:Myocardial Infarction / Q000150:complications; D011342:Procainamide / Q000627:therapeutic use; D013610:Tachycardia / Q000188:drug therapy*; D013614:Tachycardia, Paroxysmal / Q000188:drug therapy
chemical_list: D000889:Anti-Arrhythmia Agents; D008801:Mexiletine; D004110:Diltiazem; D004206:Disopyramide; D011342:Procainamide