The first action potential is produced by a small group of specialized cardiac cells, called the pacemaker cells, which are located in the border zone between the sinus venosus and the atrium. Because all cardiac muscle cells are electrically connected, this action potential can rapidly spread ...
This is explained by a significant increase in oxidation of RyR2. Calcium transients are increased in amplitude, and sarcoplasmic reticulum (SR) calcium stores are increased in PPARg cardiomyocytes. Computer modeling of the cardiac action potential demonstrates that long QT contributes to increased SR ...
was explained by greater difficulty controlling sad pictures and suppressing them in memory, thus supporting the relationship between forgetting and heart rate modulation. To confirm that the cardiac inhibition observed for disgusting material was mediated by neural mechanisms initiated during the inhibitory ...
Upregulation of Ndufs1 expression alleviated this damage, which could be explained by improved complex I activity. Increased ROS generation can promote apoptosis through multiple pathways36,37. This study focused on direct damage to DNA in the nucleus due to elevated ROS levels and the activation ...
These cases reveal that the mechanism by which a unipolar stimulation induces arrhythmias can be explained in the framework of the bidomain model with unequal anisotropy ratios. In contrast, none of the examined mechanisms provide an adequate explanation for the induction of rotors by cross-field ...
This is explained by >50% reduction in SR Cacontent in TG versus WT. Peak Cacurrent () was slightly increased, and action potential duration was prolonged in TG versus WT. Despite lower SR Caload and diastolic [Ca], fractional SR Carelease was increased and resting spontaneous SR Carelease...
action potential. Elevated intracellular sodium triggers the influx of Ca2+, which occurs slowly and is represented by the plateau region of the cardiac action potential. The influx of calcium results in efflux of potassium out of the myocardium. The Na1/K+exchange occurs at a later stage of ...
Exacerbation of such heterogeneities or the emergence of dynamic factors can produce repolarization alternans, which are beat-to-beat alternations in the action potential time course. Traditionally, this was explained by restitution, but additional factors, such as cardiac memory, calcium handling ...
Spatial distribution of activation time (AT) and action-potential duration (APD) as measured after the fifth stimulus delivered at the apex. (Top row) computational model showing the biventricular geometry and cutting planes, with stimulation sites indicated with a star. (Middle row) AT maps for...
Abstract Of the ions involved in the intricate workings of the heart, calcium is considered perhaps the most important. It is crucial to the very process that enables the chambers of the heart to contract and relax, a process called excitation–contraction coupling. It is important to understand...