Page 46 - Rapid Review of ECG Interpretation in Small Animal Practice, 2nd Edition

Treatment of Arrhythmias

Table 4.1 Drugs for treatment of supraventricular arrhythmias
VetBooks.ir Drug Administration per os Parenteral administration Comments

Diltiazem HCl: Dog: 0.5–2 mg/kg TID
Intravenous dosing can cause
Dog: 0.05–0.25 mg/kg IV
(Cardizem); Dilacor XR: 2.5–4.5 mg/kg bolus followed by transient hypotension and
(Extended BID CRI: 2–6 µg/kg/min AV nodal block
release: Cat: Cat: 0.1–0.4 mg/kg, IV
Dilacor XR) Dilacor XR: 30–60 mg/cat bolus over ∼1 minute
SID to BID followed by
CRI: Titrate to effect
2–6 µg/kg/min
Digoxin Dog: 0.0025–0.0035 mg/kg Do not exceed 0.25 mg per
2
BID (or 0.11 mg/m BID) dog BID
Cat: 0.03125 mg/cat every
other day
Procainamide Dog: 5–15 mg/kg IV bolus Can decrease contractility
slowly over 2 minutes,
CRI: 25–50 µg/kg/min
Esmolol HCl Dog and cat: 50–100 µg/ Can decrease contractility;
kg IV bolus, repeat up to can combine with any other
max 500 µg/kg IV antiarrhythmic; use with
CRI: Titrate to effect: caution in combination with
50–200 µg/kg/min procainamide
Atenolol Dog: 0.5–2 mg/kg SID to BID Titrate to effect; can decrease
Cat: 6.25–12 mg SID to BID contractility
Amiodarone Dog: 5–15 mg/kg BID for Dog: 2 mg/kg IV bolus Can combine with atenolol for
1–2 weeks (loading dose), slowly over 10 min refractory supraventricular
then 6–15 mg/kg SID CRI: 0.8 mg/kg/h for 6 h, tachycardia
(maintenance dose) the 0.4 mg/kg/h Aqueous (water-based)
formulations are better
tolerated than polysorbate
80/alcohol-based
formulations
Sotalol Dog: 1.5–2.5 mg/kg BID
Cat: 10 mg/cat BID
Abbreviations: CRI, continuous rate infusion; IV, intravenous.

primary AF is avoidance of structural or functional Focal (ectopic) atrial tachycardia (FAT)
myocardial remodeling that results secondary to Ideally, the rapidly firing atrial focus, which is the
chronic AF. Recurrence of AF after cardioversion underlying mechanism, is suppressed using sotalol,
is unpredictable. Pre-treatment with amiodarone amiodarone, or procainamide (see Table 4.1).
or sotalol may improve the chances of successful However, similar to AF and AFL, slowing of
cardioversion. AV node conduction with a CCB or BB can be
used either with or without these drugs to reduce
Atrial flutter (AFL) the ventricular response rate. Digoxin is usually
Treatment of AFL is similar to treatment of AF, and ineffective for management of FAT.
ventricular rate control via slowing of the AV node
with a CCB or BB is commonly performed (for Atrioventricular re-entry tachycardia (AVRT)
drug dosages, see treatment for AF and Table 4.1). Treatment of AVRT, especially in animals with
Medical conversion of AFL to sinus rhythm with syncope, lethargy, or congestive heart failure,
antiarrhythmic drugs such as a potassium-channel typically involves a CCB or BB. For acute
blocker (sotalol) is rarely achieved in dogs. management of dogs with incessant tachycardia,
Radiofrequency ablation has been used successfully intravenous diltiazem or esmolol is commonly
in a small number of dogs. administered, followed by titration to oral dosing.
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