Page 2102 - Cote clinical veterinary advisor dogs and cats 4th

Wolff-Parkinson-White Syndrome 1049.e3

• Thoracic radiographs • Antiarrhythmic drug therapy is used to • May require Holter monitoring (rarely,
multiple Holters) for documentation
○ Assess cardiac silhouette (normal to control tachyarrhythmias if the owner is • Even dogs with tachycardiomyopathy and
VetBooks.ir ○ Assess pulmonary vasculature and lung • Pimobendan, neurohormonal modulators, CHF can be cured with successful ablation Diseases and Disorders
unable to proceed with catheter ablation.
severely enlarged).
and diuretics for tachycardia-induced
fields (for congestion and edema).
of the AP.
• Physical tests
○ Vagal maneuver may terminate a tachyar- cardiomyopathy Technician Tips
rhythmia by inducing transient AV nodal Behavior/Exercise Teaching the owner to count the heart rate at
blockade but generally is unsuccessful. Restricted exercise is recommended until home for regular monitoring is very important
antiarrhythmic control and control of CHF in these cases, particularly for those in which
Advanced or Confirmatory Testing signs are achieved. medical management is chosen rather than the
• Holter monitoring can be helpful in ablation procedure.
capturing intermittent pre-excitation or Drug Interactions
tachyarrhythmias. • Potential interactions between digoxin and Client Education
• Drug administration: IV lidocaine is suc- several antiarrhythmic and commonly used • Monitor heart rate carefully at home.
cessful in blocking many but not all APs drugs. • Sustained tachyarrhythmias are life-
and rarely terminates other narrow complex • Beta-agonists or other stimulants are threatening.
tachyarrhythmias. It can serve as a diagnostic contraindicated. • Curative procedures are available.
and therapeutic test. IV diltiazem can
terminate AV reciprocating tachycardia by Possible Complications SUGGESTED READING
inducing AV nodal block, but it also can • Tachycardia-induced cardiomyopathy Wright KN, et al: Atrioventricular accessory pathways
terminate certain other tachyarrhythmias. • CHF in 89 dogs: clinical features and outcome after
Blood pressure (BP) monitoring and resus- • Sudden death radiofrequency catheter ablation. J Vet Intern Med
citation equipment should be available. • Side effects of antiarrhythmic drugs 32:1517-1529, 2018.
• Electrophysiologic testing definitively
establishes the presence or absence of an Recommended Monitoring ADDITIONAL SUGGESTED
AP and its location along the AV groove. • Follow-up exam, ECG, and Holter monitor- READINGS
Radiofrequency catheter ablation can be ing: frequency depends on the severity of the Santilli RA, et al: Anatomic distribution and elec-
curative during the same study. tachyarrhythmias documented. trophysiologic properties of accessory pathways in
• Radiographic and echocardiographic moni- dogs. J Am Vet Med Assoc 231:393-398, 2007.
TREATMENT toring for dogs with tachycardia-induced Santilli RA, et al: Radiofrequency catheter ablation of
cardiomyopathy: with adequate control of accessory pathways in the dog: the Italian experi-
Treatment Overview tachyarrhythmias (particularly with a curative ence. J Vet Cardiol 20:384-397, 2018.
Goals of treatment are to terminate any tachyar- ablation procedure), myocardial function Wright KN: Assessment and treatment of supraven-
tricular tachyarrhythmias. In Bonagura JD, editor:
rhythmia present, control its recurrence, and and chamber dilation should significantly Kirk’s Current veterinary therapy XIII, Philadelphia,
control signs of congestive heart failure (CHF) improve within 3 months. 2000, Saunders, pp 726-730.
and hypotension. Wright KN: Interventional catheterization for tachyar-
PROGNOSIS & OUTCOME rhythmias. Vet Clin North Am Small Anim Pract
Acute General Treatment 34:1171-1185, 2004.
• Incessant narrow complex tachyarrhythmias: • Excellent with radiofrequency catheter
aimed at slowing AV nodal conduction or ablation RELATED CLIENT EDUCATION
blocking the AP: lidocaine 2-8 mg/kg total • Fair long term with antiarrhythmic drug SHEETS
dose IV or diltiazem 0.125-0.35 mg/kg, slow administration
IV (in 2 mg/kg boluses) over 4-5 minutes is • Poor if tachyarrhythmias are not controlled: pro- Consent to Perform Echocardiography
most commonly used. Procainamide 6-8 mg/ gressive cardiomyopathic changes (eventually Heart Failure
kg slow IV over 5 minutes or amiodarone not completely reversible) and recurrent CHF
(without preservatives or Nexterone to reduce result. Sudden death becomes more common. AUTHOR: Kathy Wright, DVM, DACVIM
risk of side effects) 3-5 mg/kg slow IV over EDITOR: Meg M. Sleeper, VMD, DACVIM
10-15 minutes can also be successful in PEARLS & CONSIDERATIONS
terminating OAVRT.
• Synchronized direct current (DC) cardio- Comments
version can be used after the patient is • WPW is an important differential diagnosis
anesthetized or unconscious if drugs are in a young (<6 years old) dog presenting
unsuccessful. with DCM-like signs.
Chronic Treatment
• Radiofrequency catheter ablation of the AP
is a curative procedure.

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