Comparison of the effects of four antiarrhythmic treatments for familial ventricular arrhythmias in Boxers.
OBJECTIVE
To evaluate the effect of 4 antiarrhythmic treatment protocols on number of ventricular premature complexes (VPC), severity of arrhythmia, heart rate (HR), and number of syncopal episodes in Boxers with ventricular tachyarrhythmias.


METHODS
Randomized controlled clinical trial.


METHODS
49 Boxers.


METHODS
Dogs with > 500 VPC/24 h via 24-hour ambulatory ECG (AECG) were treated with atenolol (n = 11), procainamide (11), sotalol (16), or mexiletine and atenolol (11) for 21 to 28 days. Results of pre- and posttreatment AECG were compared with regard to number of VPC/24 h; maximum, mean, and minimum HR; severity of arrhythmia; and occurrence of syncope.


RESULTS
Significant differences between pre- and posttreatment number of VPC, severity of arrhythmia, HR variables, or occurrence of syncope were not observed in dogs treated with atenolol or procainamide. Significant reductions in number of VPC, severity of arrythmia, and maximum and mean HR were observed in dogs treated with mexiletine-atenolol or sotalol; occurrence of syncope was not significantly different between these 2 treatment groups.


CONCLUSIONS
Treatment with sotalol or mexiletine-atenolol was well tolerated and efficacious. Treatment with procainamide or atenolol was not effective.
Meurs
Kathryn M
KM
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210, USA.
Spier
Alan W
AW
Wright
Nicola A
NA
Atkins
Clarke E
CE
DeFrancesco
Teresa C
TC
Gordon
Sonya G
SG
Hamlin
Robert L
RL
Keene
Bruce W
BW
Miller
Matthew W
MW
Moise
N Sydney
NS
D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000662:veterinary*; D001262:Atenolol / Q000627:therapeutic use; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D004359:Drug Therapy, Combination; D006339:Heart Rate; D008801:Mexiletine / Q000627:therapeutic use; D011342:Procainamide / Q000627:therapeutic use; D011897:Random Allocation; D013015:Sotalol / Q000627:therapeutic use; D013575:Syncope / Q000188:drug therapy / Q000662:veterinary*; D016896:Treatment Outcome; D018879:Ventricular Premature Complexes / Q000188:drug therapy / Q000662:veterinary*
D000889:Anti-Arrhythmia Agents; D008801:Mexiletine; D001262:Atenolol; D013015:Sotalol; D011342:Procainamide