Anatomic distribution and electrophysiologic properties of accessory atrioventricular pathways in dogs.
OBJECTIVE
To evaluate the anatomic distribution and electrophysiologic properties of accessory pathways (APs) in dogs.


METHODS
Case series.


METHODS
10 dogs with tachyarrhythmias associated with an AP.


METHODS
Each dog underwent electrophysiologic testing to determine the inducibility of documented and undocumented arrhythmias and to identify location, conduction properties, and antegrade and retrograde effective refractory periods of the APs. Radiofrequency catheter ablation was then performed.


RESULTS
15 APs were identified; 7 dogs each had a single AP, and 3 had multiple APs. Fourteen of the 15 APs were right-sided (6 right free wall, 4 posteroseptal, 3 midseptal, and 1 anteroseptal), and 1 was left-sided (left free wall). All APs conducted in an all-or-none fashion. Unidirectional retrograde conduction was observed in 11 APs, and bidirectional conduction was observed in 4. All documented tachyarrhythmias could be induced during electrophysiologic testing; atrial fibrillation was also inducible in 2 dogs. Mean +/- SD cycle duration of orthodromic atrioventricular reciprocating tachycardia was 215.80 +/- 44.87 milliseconds. Mean shortest R-R interval during atrial fibrillation was 247.33 +/- 83.17 milliseconds.


CONCLUSIONS
Results suggested that in dogs, most APs are right-sided, had unidirectional retrograde conduction, and are associated with various arrhythmias, including orthodromic atrioventricular reciprocating tachycardia and atrial fibrillation without evidence of pre-excitation.
Clinica Veterinaria Malpensa, Via Marconi, 27, 21017 Samarate, Varese, Italy.
Roberto A
RA
Santilli
Gianmario
G
Spadacini
Paolo
P
Moretti
Manuela
M
Perego
Alberto
A
Perini
Serena
S
Crosara
Alberto
A
Tarducci
D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000662:veterinary; D001283:Atrioventricular Node / Q000503:physiopathology*; D004283:Dog Diseases / Q000503:physiopathology*; D004285:Dogs; D004594:Electrophysiology / Q000379:methods*; D006329:Heart Conduction System / Q000503:physiopathology*; D008297:Male; D013610:Tachycardia / Q000503:physiopathology / Q000662:veterinary*; D013617:Tachycardia, Supraventricular / Q000503:physiopathology / Q000662:veterinary