ABSTRACT
A five-year-old, female-spayed boxer was referred for frequent and medically refractory paroxysmal supraventricular tachycardia. Diagnostic evaluation found no underlying structural heart or systemic diseases. Three-dimensional electroanatomical mapping and radiofrequency ablation were pursued. Activation mapping of normal sinus rhythm demonstrated the location of the sinus node in the posterolateral region of the right atrium. Activation mapping of the tachyarrhythmia identified a centrifugal activation pattern originating from the right atrium at the posterolateral aspect of the tricuspid valve orifice, suggestive of focal atrial tachycardia. A total of 10 ablation lesions were delivered to the earliest activation site. The dog recovered without complications and no recurrence of supraventricular tachycardia was noted on subsequent follow-ups.
Subject(s)
Catheter Ablation , Dog Diseases , Tachycardia, Ectopic Atrial , Tachycardia, Supraventricular , Dogs , Female , Animals , Catheter Ablation/veterinary , Tachycardia, Ectopic Atrial/diagnosis , Tachycardia, Ectopic Atrial/surgery , Tachycardia, Ectopic Atrial/veterinary , Tachycardia, Supraventricular/diagnosis , Tachycardia, Supraventricular/surgery , Tachycardia, Supraventricular/veterinary , Heart Atria , Sinoatrial Node , Electrocardiography , Dog Diseases/diagnostic imaging , Dog Diseases/surgeryABSTRACT
A 1.5-year-old, female-spayed mix-breed dog was presented with recurrent episodes of shaking and excessive panting attributed to drug-refractory ventricular arrhythmia (VA) characterized predominantly by incessant periods of ventricular bigeminy. The VA had a narrow QRS morphology, suggestive of an origin near the His bundle or fascicular system. Diagnostic evaluation found no structural heart disease or underlying etiology. Three-dimensional electroanatomic mapping and radiofrequency catheter ablation were pursued. Voltage mapping demonstrated normal bi-ventricular voltage (≥1.5 mV) without any fractionated or multicomponent electrograms, indicating the absence of ventricular myocardial scar. Pace mapping identified an endocardial origin of the VA at the basal anterior septum of the left ventricle, distal to the His bundle and near the left bundle branch. Two ablation lesions were delivered to this site, and a left bundle branch block was temporarily induced. The dog recovered uneventfully. One month later, the owners reported a remarkable improvement in clinical signs, and follow-up 48-h Holter monitor found complete resolution of VA.