<prompt> Digoxin is used for treatment of congestive hea failure. It acts by inhibiting:-Na K ATPaseH K ATPaseNa H ATPaseNa K 2 Cl- cotranspoer  <response>: Digoxin acts by inhibiting NaKATPase of myocardial fibres by binding to its extracellular face- Accumulation of sodium in the cardiac cell- increased intracellular calcium. This Ca2 is shifted to sarcoplasmic reticulum with the help of SERCA for storage. Thus, during systole, entry of calcium from membrane Ca2 channels triggers release of high amount of Ca2 from the sarcoplasmic reticulum and result in increased contractility. 