Tests on former vice president Dick Cheney showed 'evidence of a mild heart attack,' according to an aide.

Cheney assistant Peter Long issued a statement Monday, saying the 69-year-old Cheney was resting comfortably at George Washington University Hospital and his doctors were evaluating the situation. Cheney is expected to be released from the hospital in the next couple of days, according to officials.

Cheney has a history of heart problems, including four heart attacks starting at age 37.

Cheney had bypass surgery in 1988 as well as two later angioplasties to clear narrowed coronary arteries. Bypasses tend to last about a decade before the rerouted blood vessels start to clog.

In 2001, he had a special pacemaker implanted in his chest. In addition, doctors in 2008 restored a normal rhythm to his heart with an electric shock. It was the second time in less than a year that Cheney had experienced and been treated for an atrial fibrillation, an abnormal rhythm involving the upper chambers of the heart.

The former vice president has kept a high profile since leaving the White House. He has sparred with the Obama administration over plans to close the U.S. detention facility for terror suspects at Guantanamo Bay, Cuba, and hold the trials of several high-profile detainees in civilian courts rather than military tribunals.

He made a surprise appearance last week at the Conservative Political Action Conference, where he accompanied his daughter Liz. He was greeted with chants of "Run, Dick, Run," but said "I am not going to do it."

Among his extensive government service, Cheney served as defense secretary under President George H.W. Bush.