(CNN) - The cause for former Vice President Dick Cheney's hospitalization is related to his recurring heart trouble, a family friend of Cheney's told CNN said Sunday.
Cheney was suffering from atrial fibrillation, or irregular heart rhythm, the friend said.
Cheney was admitted to George Washington University Hospital on Friday as a result of "progressive retention of fluid related to his coronary artery disease," Cheney's office said.
At the hospital, Cheney was placed on intravenous medication and his condition has "markedly improved," his office said in a statement Saturday.
On Sunday, Cheney's daughter, Liz Cheney, said that the former vice president was "feeling better" and would hopefully be released Monday.
Updated: 10:20 a.m.
Geat news; hope he continues to improve.
Congestive heart failure – lost a lot of friends to that younger than Cheenee. It's a very agressive problem.
Godspeed, Mr. Vice President. You're a true American hero.
Take care of yourself Mr. Vice President!
Cheney has the best healthcare coverage in the world and all Americans deserve the same.
While I am no fan or supporter of yours, I do wish you a speedy recovery.