Development of an ovine model of XXXX .

@entity1 @entity64 @entity742 @entity713 @entity2224 @entity616
BACKGROUND: Complete @entity616 is a significant clinical problem that can limit the quality of life in affected @entity1 . To understand the pathophysiology of this condition and provide for development of novel therapies, we sought to establish a large animal model of permanent, pacemaker-dependent @entity713 ( @entity713 ) that mimics the size and growth characteristics of pediatric @entity1 . MATERIALS AND METHODS: We utilized nine immature @entity742 weighing 10.5    1.4 kg. After implantation of dual-chamber pacemaker devices with fixed leads, @entity713 was produced by interrupting His-bundle conduction using radio-frequency ablation at the base of the non-coronary cusp of the aortic valve. Ablations (30 to 60 s in duration) were performed under fluoroscopic guidance with electrophysiological monitoring. Interrogation of pacemakers and electrocardiography (ECG) determined the persistence of @entity616 . Ovine hearts were also examined immunohistochemically for localization of conduction tissue. RESULTS: @entity713 was produced in eight animals using an atypical approach from the left side of the heart. One animal died due to @entity2224 during ablation proximal to the tricuspid annulus and one lamb was sacrificed postoperatively due to @entity64 . Four @entity742 were kept for long-term follow-up (109.8    32.9 d) and required continuous ventricular pacing attributable to lasting @entity713 , despite significant increases in body weight and size. CONCLUSIONS: We have created a large animal model of @entity616 that is stable and technically practicable. We anticipate that this lamb model will allow for advancement of cell-based and other innovative treatments to repair complete @entity616 in @entity1 .
