Atrioventricular accessory pathways in 89 dogs: Clinical features and outcome after radiofrequency catheter ablation

Abstract

BackgroundAtrioventricular accessory pathways (APs) in dogs have been reported rarely. Data regarding clinical presentation and long‐term outcome after radiofrequency catheter ablation (RFCA) are limited.Hypothesis/ObjectivesTo study clinical features, electrophysiologic characteristics, and outcome of RFCA in dogs with APs.AnimalsEighty‐nine dogs presented consecutively for RFCA of APs.MethodsCase series.ResultsLabrador retrievers (47.2% of dogs) and male dogs (67.4% of dogs) were most commonly affected. Labrador retrievers were more likely to be male than non‐Labrador breeds (P = .043). Clinical signs were nonspecific and most commonly included lethargy and gastrointestinal signs. Concealed APs were more prevalent in Labrador retrievers than other breeds (P = .001). Right‐sided APs (91.7%) predominated over left‐sided (8.3%). Tachycardia‐induced cardiomyopathy (TICM) occurred in 46.1% of dogs, with complete resolution or substantial improvement noted on one‐month postablation echocardiograms. Radiofrequency catheter ablation successfully eliminated AP conduction long term in 98.8% of dogs in which it was performed. Complications occurred in 5/89 dogs. Recurrence in 3 dogs was eliminated long term with a second procedure.Clinical Importance/ConclusionsAccessory pathways are challenging to recognize in dogs because of nonspecific clinical signs, frequency of concealed APs that show no evidence of their presence during sinus rhythm, and intermittent occurrence of tachyarrhythmias resulting from APs. Tachycardia‐induced cardiomyopathy commonly occurs with AP‐mediated tachycardias and should be considered in any dog presenting with a dilated cardiomyopathic phenotype because of its good long‐term prognosis with rhythm control. Radiofrequency catheter ablation is a highly effective method for eliminating AP conduction and providing long‐term resolution.

Cardioversion of supraventricular tachycardia in a cat with suspected Wolff–Parkinson–White syndrome in the absence of structural cardiac disease

“…6 AV APs are anomalous bypass tracts typically composed of working myocardial cells. 22 Such APs can form the retrograde limb of a macro-re-entrant circuit using the AV node as the antegrade limb, resulting in a regular, narrow complex tachyarrhythmia known as OAVRT, 8 as suspected in our case. If the AP is capable of anterograde conduction, an ECG recorded during sinus rhythm may demonstrate VPE, characterised by a short PR interval and the presence of a delta wave (termed 'manifest' AP), 23 which was consistently present in this case.…”

“…Therapy for AP-associated SVT aims to impair one of the arms of the re-entrant circuit. 22 Calcium channel blockers (e.g., diltiazem) and β-blocking agents (e.g., esmolol, atenolol) slow the conduction and prolong the refractory period in the AV node. 30 The deleterious cardiovascular effects observed following esmolol administration could have been due to its negative inotropic influence, worsening the hypotension.…”

Lidocaine for chemical cardioversion of orthodromic atrioventricular reciprocating tachycardia in dogs

“…The clinical tachyarrhythmia had to have regular R-R intervals, a short fixed RP 0 interval that was less than the P 0 R interval, immediate arrhythmia termination if second-degree AV block occurred, and be proven to be OAVRT at subsequent electrophysiologic study (EPS). 12 Lidocaine hydrochloride (Vedco, St. Joseph, Missouri) was injected via a cephalic catheter at an initial dose of 2 mg/kg over 20-30 seconds. If no conversion of the tachyarrhythmia occurred after 2 minutes and no adverse effects developed, an additional 2 mg/kg IV bolus was administered, to a total cumulative dose of 8 mg/kg.…”

News

“…One of the most profoundly influential books I have read in my adult life is a book called Drive by Daniel Pink (closely followed by books about capsule wardrobes, but that story belongs in a column for another publication). 1 In this book, Daniel takes the reader through a theory of motivation. It references the greatest hits of literature and doesn't leave out 'Uncle Maslow'.…”

“…The constitution of the Australian Veterinary Association (AVA) states its main objective is to promote and advance veterinary and allied sciences in Australia. 1 To do this, the constitution outlines, the AVA is to act as a medium through which members and general veterinary profession (non-members) can communicate, interact, and exchange skills. It is to consider questions of policy and encourage, facilitate and enter into discussions with any person to advance and promote veterinary and allied sciences in Australia.…”