Effect of selective I inhibition by XAF-1407 in an equine model of tachypacing-induced persistent atrial fibrillation.

Background And Purpose: Inhibition of the G-protein gated ACh-activated inward rectifier potassium current, I may be an effective atrial selective treatment strategy for atrial fibrillation (AF). Therefore, the anti-arrhythmic and electrophysiological properties of a novel putatively potent and highly specific I inhibitor, XAF-1407 (3-methyl-1-[5-phenyl-4-[4-(2-pyrrolidin-1-ylethoxymethyl)-1-piperidyl]thieno[2,3-d]pyrimidin-6-yl]azetidin-3-ol), were characterised for the first time in vitro and investigated in horses with persistent AF.

Experimental Approach: The pharmacological ion channel profile of XAF-1407 was investigated using cell lines expressing relevant ion channels.

Effect of induced chronic atrial fibrillation on exercise performance in Standardbred trotters.

Background: Atrial fibrillation (AF) is the most common arrhythmia affecting performance in horses. However, no previous studies have quantified the performance reduction in horses suffering from AF.

Objectives: To quantify the effect of AF on maximum velocity (V ), maximum heart rate (HR ), heart rate recovery (T ), hematologic parameters and development of abnormal QRS complexes.