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Rate dependence of the action potential is a fundamental property of cardiac cells and alterations can lead to severe cardiac diseases including cardiac arrhythmia and sometimes sudden death. [3] Action potential activity within the heart can be recorded to produce an electrocardiogram (ECG). This is a series of upward and downward spikes ...
Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a class of drugs that are used to suppress abnormally fast rhythms (tachycardias), such as atrial fibrillation, supraventricular tachycardia and ventricular tachycardia. Many attempts have been made to classify antiarrhythmic agents.
Ventricular action potential. The action potential of a ventricular myocyte. In electrocardiography, the ventricular cardiomyocyte membrane potential is about −90 mV at rest, [1] which is close to the potassium reversal potential. When an action potential is generated, the membrane potential rises above this level in five distinct phases.
The cardiac conduction system (CCS, also called the electrical conduction system of the heart) [1] transmits the signals generated by the sinoatrial node – the heart 's pacemaker, to cause the heart muscle to contract, and pump blood through the body's circulatory system. The pacemaking signal travels through the right atrium to the ...
When the action potential triggers the muscles in the atria to contract (atrial systole), the pressure within the atria rises further, pumping blood into the ventricles. During ventricular systole, pressure rises in the ventricles, pumping blood into the pulmonary trunk from the right ventricle and into the aorta from the left ventricle. [1]
A Wiggers diagram, named after its developer, Carl Wiggers, is a unique diagram that has been used in teaching cardiac physiology for more than a century. [1][2] In the Wiggers diagram, the X-axis is used to plot time subdivided into the cardiac phases, while the Y-axis typically contains the following on a single grid: The Wiggers diagram ...
Pacemaker potential. In the pacemaking cells of the heart (e.g., the sinoatrial node), the pacemaker potential (also called the pacemaker current) is the slow, positive increase in voltage across the cell 's membrane (the membrane potential) that occurs between the end of one action potential and the beginning of the next action potential.
The simplest models of the action potential are the "flush and fill" models (also called "integrate-and-fire" models), in which the input signal is summed (the "fill" phase) until it reaches a threshold, firing a pulse and resetting the summation to zero (the "flush" phase). [3][21][22] All of these models are capable of exhibiting entrainment ...