Page 2705 - Cote clinical veterinary advisor dogs and cats 4th

Atrial Fibrillation

ECG diagnosis: Atrial fibrillation (AF)
VetBooks.ir Do the patient’s electro-

cardiograms (ECGs) show
that the AF began in the
preceding 72 hours?

Yes No, or not sure

Are the atria structurally normal Treatment for
(radiographs, echocardiogram)? chronic AF

Yes No
Does the patient
Consider conversion Treatment with beta-blocker or AF have cardiogenic
(atrial defibrillation) calcium channel blocker PO if heart persists pulmonary edema?
or watchful waiting rate is rapid (as defined below)
Yes No
• Electrical • Watchful waiting if rate is
defibrillation not excessive Treat with furosemide Is the ventricular rate rapid?
(under short-acting • Triggering event gone? • 140 bpm (big dog)
intravenous [IV] Opiate drugs • 180 bpm (small dog)
general anesthe- Gastric dilation/volvulus • 240 bpm (cat)
sia) at 100 to 200 (GDV) Has pulmonary
joules Other gastrointestinal edema resolved? No Yes

• Amiodarone (GI) or vagal event
Hypoadrenocorticism
• Sotalol Hit by car (HBC)
• Quinidine Postpericardiocentesis No Treat with negative dromo-
• Possibly ranolazine antiarrhythmic tropic drug(s) (AV nodal–
Hypothyroidism treatment delaying agents) based on
Volume load
Yes No underlying heart structure
• Dilated cardiomyopathy
(DCM)
Is the ventricular rate rapid? Is the ventricular rate excessive at rest? Digoxin and
Diltiazem

• 140 bpm (big dog) • 180 bpm (big dog) • Hypertrophic cardiomyo-
• 180 bpm (small dog) • 200 bpm (small dog) pathy (HCM) or left ventric-
• 240 bpm (cat) • 300 bpm (cat) ular hypertrophy (LVH)
Beta-blocker or
No Yes Yes No Diltiazem or
Both
• Normal heart
No antiarrhythmic Tachycardia may be • Increase diuretic Diltiazem or
treatment contributing to dosage until signs Digoxin or
congestive heart failure of edema have Beta-blocker or
(CHF). Consider com- improved or Combination
Treatment with negative bination or monotherapy resolved or until
dromotropic drug(s) (AV nodal– with negative dromotropes: maximum diuretic
delaying agents) based on • IV diltiazem (low, dosage is reached
underlying heart structure: incremental doses) • Change diuretic to
• Dilated cardiomyopathy (DCM) • Digoxin (fixed dosage, torsemide, or add
Digoxin not titrated) 2nd diuretic Clinical Algorithms
Diltiazem • IV beta-blocker (low, (thiazide)
• HCM or LVH incremental doses if IV • Give diuretic IV
Beta-blocker or diltiazem insufficient) bolus or constant
Diltiazem or Goal is to decrease rate infusion
Both (CRI) to improve
• Normal heart heart rate slightly efficacy
Beta-blocker or (10% to 20%)
Digoxin or
Diltiazem or
Combination
Has pulmonary
edema resolved?
Yes No

(Modified from Ettinger SJ, Feldman EC: Textbook of veterinary internal medicine, ed 6, St. Louis, 2005, Saunders; and Ettinger SJ, Feldman EC, Côté E: Textbook of veterinary
internal medicine, ed 8, St. Louis, 2017, Saunders.)
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