Complete atrioventricular block under epidural ropivacaine infusion in a patient with first-degree atrioventricular block and myasthenia gravis: a case report.

Background: First-degree atrioventricular block (AVB) may lead to complete AVB. Herein, we present a case of a complete AVB under thoracic epidural catheter infusion of ropivacaine with fentanyl in a patient with first-degree AVB and myasthenia gravis.

Case Presentation: A 74-year-old woman with first-degree AVB underwent thymectomy for myasthenia gravis.

The cardiac pacemaker-specific channel Hcn4 is a direct transcriptional target of MEF2.

Aims: Hcn4, which encodes the hyperpolarization-activated, cyclic nucleotide-sensitive channel (I(h)), is a well-established marker of the cardiac sino-atrial node. We aimed to identify cis-elements in the genomic locus of the Hcn4 gene that regulate the transcription of Hcn4.

Methods And Results: We screened evolutionarily conserved non-coding sequences (CNSs) that are often involved in the regulation of gene expression.

NRSF regulates the developmental and hypertrophic changes of HCN4 transcription in rat cardiac myocytes.

The HCN4 channel shows differential expression patterns during the embryonic development and hypertrophy of hearts. Briefly, HCN4 expression is maximally activated in embryonic hearts and quickly diminishes after birth. However, it is reactivated during cardiac hypertrophy.

Mutations in two matrix metalloproteinase genes, MMP-2 and MT1-MMP, are synthetic lethal in mice.

The matrix metalloproteinase (MMP) family (approximately 25 members in mammals) has been implicated in extracellular matrix remodeling associated with embryonic development, cancer formation and progression, and various other physiological and pathological events. Inactivating mutations in individual matrix metalloproteinase genes in mice described so far, however, are nonlethal at least up to the first few weeks after birth, suggesting functional redundancy among MMP family members. Here, we report that mice lacking two MMPs, MMP-2 (nonmembrane type) and MT1-MMP (membrane type), die immediately after birth with respiratory failure, abnormal blood vessels, and immature muscle fibers reminiscent of central core disease.

Role of individual ionic current systems in the SA node hypothesized by a model study.

This paper discusses the development of a cardiac sinoatrial (SA) node pacemaker model. The model successfully reconstructs the experimental action potentials at various concentrations of external Ca2+ and K+. Increasing the amplitude of L-type Ca2+ current (I(CaL)) prolongs the duration of the action potential and thereby slightly decreases the spontaneous rate.

Role of individual ionic current systems in ventricular cells hypothesized by a model study.

Individual ion channels or exchangers are described with a common set of equations for both the sinoatrial node pacemaker and ventricular cells. New experimental data are included, such as the new kinetics of the inward rectifier K+ channel, delayed rectifier K+ channel, and sustained inward current. The gating model of Shirokov et al.

Regulation of cardiac inwardly rectifying potassium channels by membrane lipid metabolism.

Types and distributions of inwardly rectifying potassium (Kir) channels are one of the major determinants of the electrophysiological properties of cardiac myocytes. Kir2.1 (classical inward rectifier K(+) channel), Kir6.