label: sodium:proton antiporter activity involved in regulation of cardiac muscle cell membrane potential
label_lc: sodium:proton antiporter activity involved in regulation of cardiac muscle cell membrane potential
description: "Enables the transfer of a solute or solutes from one side of a cardiac muscle cell membrane to the other according to the reaction: Na+(out) + H+(in) = Na+(in) + H+(out). This transfer contributes to the regulation of the cardiac muscle cell plasma membrane potential."