Radiofrequency catheter ablation of concealed accessory pathways in two dogs with symptomatic atrioventricular reciprocating tachycardia

Orthodromic Atrioventricular Reciprocating Tachycardia in a Dalmatian

“…This arrhythmia had only been previously documented in Labrador Retrievers, Beagles, Boxers and English Bulldogs [3] [4] [12] [13] [14], so this appears to be the first report of OAVRT in a Dalmatian. Also, this arrhythmia has been identified in dogs with age ranging from 4 months to 11 years [4], which is consistent with the patient that we report.…”

“…To occur, the OAVRT requires a reentrant circuit containing an atrioventricular accessory pathway [3], which is constituted by muscle fibers capable of generating action potentials and electrical conduction parallel to the atrioventricular node and His-Purkinje system between the atrium and ventricles [4]. These accessory pathways are either single or multiple, usually have bidirectional conduction capability and can be classified according to its location over the atrioventricular sulcus.…”

“…In people, OAVRT is considered a common arrhythmia, affecting mainly infants and children [3]. In dogs, however, OAVRT has only been reported in a few breeds, including Boxers, Labrador Retrievers and Beagles, which aged from 4 months to 11 years [4]. Also, a greater predisposition for the occurrence of this arrhythmia has been recognized in patients with tricuspid dysplasia [3].…”

“…Also, this arrhythmia may occur either continuously, leading to a tachycardia-induced cardiomyopathy, or intermittently, resulting in signs of weakness and syncope [4]. The unceasing tachycardia is more likely to produce dilation of cardiac chambers and ventricular dysfunction, with signs ascribed to heart failure arising as cardiac output and tissue perfusion decrease [9] [10].…”

Intracardiac electrophysiological conduction parameters in adult dogs

“…Usually, EPS is performed to evaluate abnormalities of the electrical conduction system of the heart, to test the influence of various chemicals and medicines on this system, and to develop novel methods or improve existing protocols of non-pharmacological treatments of arrhythmia. In the case of dogs, apart from experimental purposes, EPS is usually performed in order to choose an appropriate (pharmacological or non-pharmacological) treatment or prior to, radiofrequency (RF) ablation (Santilli et al 2006(Santilli et al , 2010a(Santilli et al , 2010b(Santilli et al , 2011(Santilli et al , 2013Perego et al 2012). To the best of our knowledge, determination of the electrophysiological conduction parameters for selected electrophysiological parameters of dogs was a subject of only few studies (Landmark & Amlie, 1976;Pickoff et al 1983;Huerta et al 1984;Sassine et al 1984;Young et al 1986;Timour et al 1987;Traunecker, 1988;Wright et al 1996).…”