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The slope of phase 0 on the action potential waveform (see figure 2) represents the maximum rate of voltage change of the cardiac action potential and is known as dV/dt max. In pacemaker cells (e.g. sinoatrial node cells ), however, the increase in membrane voltage is mainly due to activation of L-type calcium channels.
The action potential generated by the SA node passes down the electrical conduction system of the heart, and depolarizes the other potential pacemaker cells (AV node) to initiate action potentials before these other cells have had a chance to generate their own spontaneous action potential, thus they contract and propagate electrical impulses ...
An impulse (action potential) that originates from the SA node at a relative rate of 60–100 bpm is known as a normal sinus rhythm. If SA nodal impulses occur at a rate less than 60 bpm, the heart rhythm is known as sinus bradycardia. If SA nodal impulses occur at a rate exceeding 100 bpm, the consequent rapid heart rate is sinus tachycardia ...
The slope determines the time taken to reach the threshold potential, and thus the timing of the next action potential. [ 2 ] In a healthy sinoatrial node (SAN, a complex tissue within the right atrium containing pacemaker cells that normally determine the intrinsic firing rate for the entire heart [ 3 ] [ 4 ] ), the pacemaker potential is the ...
Cardiac excitation-contraction coupling (Cardiac EC coupling) describes the series of events, from the production of an electrical impulse (action potential) to the contraction of muscles in the heart. [1] This process is of vital importance as it allows for the heart to beat in a
Several agents called "heart rate reducing agents" act by specifically inhibiting f-channel function. [3] Ivabradine is the most specific and selective I f inhibitor and the only member of this family that is now marketed for pharmacological treatment of chronic stable angina in patients with normal sinus rhythm who have a contraindication or ...
Transmission of a cardiac action potential through the heart's conduction system. It is not very well known how the electric signal moves in the atria. It seems that it moves in a radial way, but Bachmann's bundle and coronary sinus muscle play a role in conduction between the two atria, which have a nearly simultaneous systole.
This chronological list of famous watchmakers is a list of those who influenced the development of horology or gained status by their creations.