Digoxin is used to treat heart failure, usuallyalong with other medications. It is also used to treat certain types ofirregular heartbeat (such as chronic atrial fibrillation). Treating heartfailure may help maintain your ability to walk and exercise and may improve thestrength of your heart. Treating an irregular heartbeat can also improve yourability to exercise. Digoxin belongs to a class of medications called cardiacglycosides. It works by affecting certain minerals (sodium and potassium)inside heart cells. This reduces strain on the heart and helps it maintain anormal, steady, and strong heartbeat.