Feasibility of electroanatomic mapping and radiofrequency catheter ablation in Boxer dogs with symptomatic ventricular tachycardia

Abstract

Background: Treatment for Boxers with ventricular tachycardia (VT) is limited. Electroanatomic mapping (EAM) facilitates identification of arrhythmogenic substrate for radiofrequency catheter ablation (RFCA).Objective: Describe the use of EAM to guide RFCA in Boxers with VT.Animals: Five client-owned Boxers with symptomatic VT or persistent VT despite antiarrhythmic medications.Methods: Case series evaluating clinical, EAM, and before and after RFCA Holter data.Results: Sustained VT was inducible in 3 dogs, but required aggressive stimulation protocols. Low-voltage areas consistent with electroanatomic scar were found in 2 dogs, located at the right ventricular (RV) outflow tract and cranial RV. Two dogs had a focal activation pattern of VT and 1 dog had a reentrant mechanism. After RFCA, all dogs no longer collapsed and had fewer runs of VT, 3 of which had 0 runs of VT. Number of ventricular premature beats increased in 3 dogs and decreased in 2 dogs, 1 of which had nearly complete resolution of all arrhythmias. Procedural complications included ventricular fibrillation (n = 2) with successful defibrillation, bruising or hemorrhage at the vascular access site (n = 4), retroperitoneal hemorrhage (n = 1), aortic and mitral regurgitation (n = 1), onset of frequent supraventricular tachycardia (n = 1), and persistent right pelvic limb lameness (n = 1).Conclusions and Clinical Importance: Electroanatomic mapping and RFCA are feasible in Boxers with VT. Based on this small cohort, RFCA may help decrease runs of Abbreviations: %VE, percent of total ventricular beats consisting of ventricular premature complexes; AAD, antiarrhythmic drug; ARVC, arrhythmogenic right ventricular cardiomyopathy; EAM, electroanatomic mapping; EGM, electrogram; LBBB, left bundle branch block; LV, left ventricle; OTVT, outflow tract ventricular tachycardia; PES, programmed electrical stimulation; RBBB, right bundle branch block; RFCA, radiofrequency catheter ablation; RV, right ventricle; RVOT, right ventricular outflow tract; VA, ventricular arrhythmia; VE, ventricular ectopy; VPC, ventricular premature complex; VT, ventricular tachycardia. Alexandra V. Crooks and Weihow Hsue are co-first authors.