Publications by authors named "Merle Friederike Fenner"
Background: Fibroblasts maintain the extracellular matrix homeostasis and may couple to cardiomyocytes through gap junctions and thereby increase the susceptibility to slow conduction and cardiac arrhythmias, such as atrial fibrillation (AF). In this study, we used an equine model of persistent AF to characterize structural changes and the role of fibroblasts in the development of an arrhythmogenic substrate for AF.
Material And Methods: Eleven horses were subjected to atrial tachypacing until self-sustained AF developed and were kept in AF for six weeks.
Vitrification and slow freezing are the two commonly used embryo cryopreservation methods. In most studies, vitrification of intact embryos has proven superior in several respects, including cell and embryo survival and pregnancy rate. However, there is a lack of data for comparing these two methods in in vitro produced (IVP) bovine blastocysts, which have been subjected to the retrieval of trophectoderm (TE) biopsy.
View Article and Find Full Text PDFBackground: Small-conductance Ca-activated K (K2) channels have been proposed as a possible atrial-selective target to pharmacologically terminate atrial fibrillation (AF) and to maintain sinus rhythm. However, it has been hypothesized that the importance of the K2 current-and thereby the efficacy of small-conductance Ca-activated K current ( ) inhibition-might be negatively related to AF duration and the extent of AF-induced remodeling.
Experimental Approach And Methods: To address the hypothesis of the efficacy of inhibition being dependent on AF duration, the anti-arrhythmic properties of the inhibitor NS8593 (5 mg/kg) and its influence on atrial conduction were studied using epicardial high-density contact mapping in horses with persistent AF.
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.
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.