title: Increased ventricular response rate during exercise in patients with atrial fibrillation treated with theophylline.
abstract: The effect of theophylline on atrioventricular conduction in atrial fibrillation was investigated by determining ventricular response rates at rest and during exercise treadmill tests in eight patients (mean [+/- SEM] age, 64.2 +/- 2.0 years) with chronic atrial fibrillation. Tests were performed before and after 7 days of oral theophylline treatment (plasma level, 87.7 +/- 7.8 mumol/L). There was no significant change in baseline ventricular rate or duration of exercise, but the maximum ventricular rate with theophylline treatment was 12.3% +/- 2.4% higher than that with placebo (176.3 +/- 7.5 vs 158.1 +/- 8.8 beats per minute), and, during each stage of exercise, the ventricular rate with theophylline exceeded that with placebo. The increased heart rate during theophylline administration occurred without a significant difference in the exercise-induced increase in circulating plasma catecholamine levels. We conclude that treatment with theophylline may contribute to difficulties with rate control in acutely ill patients with coexisting atrial fibrillation.
authors.affiliation: Clinical Pharmacology and Gerontology Research Unit, Veterans Affairs Medical Center, Boise, Idaho 83702.
authors.forename: G L
authors.initials: GL
authors.lastname: Dattilo
authors.forename: C E
authors.initials: CE
authors.lastname: Eiriksson
authors.forename: R E
authors.initials: RE
authors.lastname: Vestal
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000097:blood / Q000503:physiopathology*; D002908:Chronic Disease; D004311:Double-Blind Method; D004837:Epinephrine / Q000097:blood; D005080:Exercise Test / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D011897:Random Allocation; D012044:Regression Analysis; D013806:Theophylline / Q000494:pharmacology*
chemical_list: D013806:Theophylline; D009638:Norepinephrine; D004837:Epinephrine