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Topic 940 Version 35.0 https://www.uptodate.com/contents/sinus-node-dysfunction-epidemiology-etiology-and-natural-history/print 15/17 7/5/23, 11:18 AM Sinus node dysfunction: Epidemiology, etiology, and natural history - UpToDate GRAPHICS Action potential currents Major cardiac ion currents and channels responsible for a ventricular action potential are shown with their common name, abbreviation, and the gene and protein for the alpha subunit that forms the pore or transporter. The diagram on the left shows the time course of amplitude of each current during the action potential, but does not accurately reflect amplitudes relative to each of the other currents. This summary represents a ventricular myocyte, and lists only the major ion channels. The currents and their molecular nature vary within regions of the ventricles, and in atria, and other specialized cells such as nodal and Purkinje. Ion channels exist as part of multi-molecular complexes including beta subunits and other associated regulatory proteins which are also not shown. Courtesy of Jonathan C Makielski, MD, FACC. Graphic 70771 Version 4.0 https://www.uptodate.com/contents/sinus-node-dysfunction-epidemiology-etiology-and-natural-history/print 16/17 7/5/23, 11:18 AM Sinus node dysfunction: Epidemiology, etiology, and natural history - UpToDate Contributor Disclosures Munther K Homoud, MD Speaker's Bureau: Abbott [Live heart dissection]. All of the relevant financial relationships listed have been mitigated. Samuel L vy, MD No relevant financial relationship(s) with ineligible companies to disclose. Susan B Yeon, MD, JD, FACC No relevant financial relationship(s) with ineligible companies to disclose. Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence. Conflict of interest policy https://www.uptodate.com/contents/sinus-node-dysfunction-epidemiology-etiology-and-natural-history/print 17/17