WASHINGTON (CNN) -- Doctors found a blood clot in Vice President Dick Cheney's left leg Monday, but he was allowed to return to work after being given blood-thinning medication, his office said.

Cheney went to visit his doctors at George Washington University after reporting "mild calf discomfort," said his spokeswoman, Megan McGinn. Doctors performed an ultrasound and found a deep venous thrombosis, or DVT, in his lower left leg, she said.

Cheney was given blood thinners, a prescription he will need to take for several months, McGinn said. But he returned to the White House soon after his appointment and went back to work, she said.

The vice president has had a history of heart ailments -- including four heart attacks dating back to 1978 -- and was briefly hospitalized in January 2006 after suffering shortness of breath. In September 2005, he underwent surgery to remove an aneurysm in an artery behind his right knee.

Cheney returned to Washington early Wednesday after a trip to Australia and Central Asia. He spoke at a Veterans of Foreign Wars conference earlier Monday.