<P> The cardiac action potential is a brief change in voltage ( membrane potential ) across the cell membrane of heart cells . This is caused by the movement of charged atoms ( called ions ) between the inside and outside of the cell , through proteins called ion channels . The cardiac action potential differs from action potentials found in other types of electrically excitable cells , such as nerves . Action potentials also vary within the heart ; this is due to the presence of different ion channels in different cells ( see below ) . </P>
<P> The cardiac action potential is a brief change in voltage ( membrane potential ) across the cell membrane of heart cells . This is caused by the movement of charged atoms ( called ions ) between the inside and outside of the cell , through proteins called ion channels . The cardiac action potential differs from action potentials found in other types of electrically excitable cells , such as nerves . Action potentials also vary within the heart ; this is due to the presence of different ion channels in different cells ( see below ) . </P>
where is the normal cardiac action potential initiated
where is the normal cardiac action potential initiated
across the cell membrane of heart cells
across the cell membrane of heart cells