Re-evaluation of the action potential upstroke velocity as a measure of the Na+ current in cardiac myocytes at physiological conditions.
BackgroundThe SCN5A encoded sodium current (I(Na)) generates the action potential (AP) upstroke and is a major determinant of AP characteristics and AP propagation in cardiac myocytes.Unfortunately, in cardiac myocytes, investigation of kinetic properties of I(Na) with near-physiological ion concentrations and temperature is technically challenging