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We report for the first time abnormalities in cardiac ventricular electrophysiology in a genetically modified murine model lacking the Scn3b gene (Scn3b(-/-)). Scn3b(-/-) mice were created by homologous recombination in embryonic stem (ES) cells. RT-PCR analysis confirmed that Scn3b mRNA was expressed in the ventricles of wild-type (WT) hearts but was(More)
BACKGROUND The SCN5A sodium channel is a major determinant for cardiac impulse propagation. We used epicardial mapping of the atria, ventricles, and septae to investigate conduction velocity (CV) in Scn5a heterozygous young and old mice. METHODS AND RESULTS Mice were divided into 4 groups: (1) young (3 to 4 months) wild-type littermates (WT); (2) young(More)
AIM To explore the physiological consequences of the ryanodine receptor (RyR2)-P2328S mutation associated with catecholaminergic polymorphic ventricular tachycardia (CPVT). METHODS We generated heterozygotic (RyR2 p/s) and homozygotic (RyR2 s/s) transgenic mice and studied Ca2+ signals from regularly stimulated, Fluo-3-loaded, cardiac myocytes. Results(More)
OBJECTIVES We investigate the extent to which the electrocardiographic (ECG) properties of intact Scn5a+/- mice reproduce the corresponding clinical Brugada syndrome phenotype and use this model to investigate the role of conduction and repolarization abnormalities in the arrhythmogenic mechanism. METHODS AND RESULTS The ECGs were obtained from(More)
AIM In contrast to extensive reports on the roles of Na(v)1.5 alpha-subunits, there have been few studies associating the beta-subunits with cardiac arrhythmogenesis. We investigated the sino-atrial and conduction properties in the hearts of Scn3b(-/-) mice. METHODS The following properties were compared in the hearts of wild-type (WT) and Scn3b(-/-)(More)
AIMS The experiments explored for atrial arrhythmogenesis and its possible physiological background in recently developed hetero-(RyR2(+/S)) and homozygotic (RyR2(S/S)) RyR2-P2328S murine models for catecholaminergic polymorphic ventricular tachycardia (VT) for the first time. They complement previous clinical and experimental reports describing increased(More)
1. Intracellular Ca(2+) overload has been associated with established atrial arrhythmogenesis. The present experiments went on to correlate acute initiation of atrial arrhythmogenesis in Langendorff-perfused mouse hearts with changes in Ca(2+) homeostasis in isolated atrial myocytes following pharmacological procedures that modified the storage or release(More)
AIMS Recent studies reported slowed conduction velocity (CV) in murine hearts homozygous for the gain-of-function RyR2-P2328S mutation (RyR2(S/S)) and associated this with an increased incidence of atrial and ventricular arrhythmias. The present experiments determined mechanisms contributing to the reduced atrial CV. METHODS AND RESULTS The determinants(More)
We explored for relationships between SCN5A haploinsufficiency, implicated in clinical arrhythmogenicity, and right ventricular (RV) conduction disorders in Langendorff-perfused, male and female, and young (3 months) and old (>12 month old) Scn5a ( +/-) and wild type (WT) hearts. The investigated conditions of genotype, age, and sex affected latencies but(More)