Ventricular repolarization is a complex electrical phenomenon which represents a crucial stage in electrical cardiac activity. It is expressed on the surface electrocardiogram by the interval between the start of the QRS complex and the end of the T wave or U wave (QT). Several physiological, pathological and iatrogenic factors can influence ventricular repolarization. It has been demonstrated that small perturbations in this process can be a potential trigger of malignant arrhythmias, therefore the analysis of ventricular repolarization represents an interesting tool to implement risk stratification of arrhythmic events in different clinical settings. The aim of this review is to critically revise the traditional methods of static analysis of ventricular repolarization as well as those for dynamic evaluation, their prognostic significance and the possible application in daily clinical practice.
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http://dx.doi.org/10.4330/wjc.v8.i1.57 | DOI Listing |
Circ Res
December 2024
Department of Biology and Genetics, McAllister Heart Institute, University of North Carolina, Chapel Hill. (W.S., J.P.-L., W.G.W., W.F.M., F.L.C.).
Background: Males and females exhibit distinct anatomic and functional characteristics of the heart, predisposing them to specific disease states.
Methods: We identified microRNA (miRNAs/miR) with sex-differential expression in mouse hearts.
Results: Four conserved miRNAs are present in a single locus on the X-chromosome and are expressed at higher levels in females than males.
Biomolecules
December 2024
Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Splaiul Independentei 91-95, 050095 Bucharest, Romania.
Cenobamate is a novel third-generation antiepileptic drug used for the treatment of focal onset seizures and particularly for multi-drug-resistant epilepsy; it acts on multiple targets: GABA receptors (EC 42-194 µM) and persistent neuronal Na currents (IC 59 µM). Side effects include QT interval shortening with >20 ms, but not <300 ms. Our in vitro cardiac safety pharmacology study was performed via whole-cell patch-clamp on HEK293T cells with persistent/inducible expression of human cardiac ion channel isoforms hNav1.
View Article and Find Full Text PDFBackground: Long QT Syndrome Type-2 (LQT2) is due to loss-of-function variants. encodes K 11.1 that forms a delayed-rectifier potassium channel in the brain and heart.
View Article and Find Full Text PDFJ Electrocardiol
December 2024
Physiology Unit, Department of Pre-Clinical Sciences, Faculty of Medical Sciences, The University of the West Indies, St. Augustine Campus, Mount Hope Hospital, Building 35, Uriah Butler Highway, Trinidad and Tobago.
Background: The aim of this simulation was to examine the utility of a novel ECG-based index of cardiac action potential (AP) triangulation, the Tstart-to-Tpeak (TsTp) interval-to-JTstart (JTs) interval ratio, for assessment of changes in AP profile imposed through variations in the duration of the plateau phase and the phase 3 repolarization.
Methods: ECGs were simulated using a realistic rabbit model based on experimental data. The AP plateau was measured at APD30, and the phase 3 was assessed as APD90-to-APD30 difference (AP durations at 90 % and 30 % repolarization, respectively).
PLoS One
December 2024
Chinese PLA Medical School, Chinese PLA General Hospital, Beijing, China.
Obesity is associated with abnormal repolarization manifested by QT interval prolongation, and oxidative stress is an important link between obesity and arrhythmias. However, the underlying electrophysiological and molecular mechanisms remain unclear. The aim of this study is to evaluate the role of obesity in potassium current in ventricular myocytes and the potential mechanism of NADPH oxidase 2 (Nox2).
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