Clinical assessment of clonidine in the treatment of new-onset rapid atrial fibrillation: a prospective, randomized clinical trial.
OBJECTIVE
The role of digoxin and verapamil in the control of ventricular response in rapid atrial fibrillation is well established. This study investigates how clonidine compares with these standard therapies in rate control for new-onset rapid atrial fibrillation. We set out to test the hypothesis that clonidine effectively reduces heart rate in patients with new-onset rapid atrial fibrillation.


METHODS
Forty patients were seen in the emergency department with new-onset (< or =24 hours' duration), stable, rapid atrial fibrillation. Eligible patients were randomized to receive either clonidine, digoxin, or verapamil. Changes in heart rate and blood pressure over 6 hours, as well as frequency of conversion to sinus rhythm were recorded and analyzed.


RESULTS
The mean reduction in heart rate over 6 hours was 44.4 beats/min (95% confidence interval [CI] 28.4-60.4 beats/min) in the clonidine group, 52.1 beats/min (95% CI 40.8-63.4 beats/min) in the digoxin group, and 41.8 beats/min (95% CI 22.5-61.0 beats/min) in the verapamil group. Analysis of variance of the heart rate changes in the 3 groups after 6 hours was not significant (P =.55). At 6 hours, 7 of 12 clonidine patients, 8 of 15 digoxin patients, and 7 of 13 verapamil patients remained in atrial fibrillation (P =.962 on chi(2)).


CONCLUSIONS
Clonidine controls ventricular rate in new-onset atrial fibrillation with an efficacy comparable to that of standard agents.
Simpson
C S
CS
Division of Cardiology, Department of Medicine, Queen's University, Kingston, Ontario, Canada. simpsonc@kgh.kari.net
Ghali
W A
WA
Sanfilippo
A J
AJ
Moritz
S
S
Abdollah
H
H
D000208:Acute Disease; D000284:Administration, Oral; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D001794:Blood Pressure / Q000187:drug effects; D003000:Clonidine / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*; D004077:Digoxin / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D014700:Verapamil / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use
D000889:Anti-Arrhythmia Agents; D004077:Digoxin; D014700:Verapamil; D003000:Clonidine