Page 141 - Rapid Review of ECG Interpretation in Small Animal Practice, 2nd Edition
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Answer 58 New Holter Monitoring ECG Cases
Answer 58
VetBooks.ir 1 The arrhythmia count has markedly increased under sotalol therapy, indicating a proarrhythmic effect
by this potassium-channel blocking agent in this dog.
2 The goal is to reduce the number of VPCs by >80% in order to account for day-to-day variation in
the number of VPCs. Sotalol failed to decrease the total number of VPCs. An antiarrhythmic with
a different mechanism of action might be tried. In this case, sotalol was replaced with mexiletine
(sodium-channel blocker) and atenolol (beta-blocker) and eliminated of runs of VT and reduced total
ventricular ectopy percentage to <0.1%.
Treatment VPC/24 h Runs of VT/24 h Ventricular ectopic beats as percentage
of total number of beats/24 h
Pre-treatment 5,822 42 6.2%
Sotalol 14,681 295 13.8%
Mexiletine plus atenolol 29 0 <0.1%
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