Vice President Dick Cheney's high-tech pacemaker is working properly and has not been activated by any irregular heartbeats, according to his annual physical on Saturday that showed his overall heart condition was stable.
The 65-year-old Cheney, who has a long history of heart ailments, had an electrocardiogram and imaging to check on repaired aneurysms on the back of his knees, his spokeswoman said.
Doctors also checked the condition of an implantable cardioverter defibrillator, which was placed in his chest in June 2001.
Cheney has had four attacks; the first in 1978, when he was 37, and the fourth on Nov. 22, 2000, after the election that made George W. Bush president.
"The vice president's cardiac status remains stable, his ICD is functioning properly and has not treated any arrhythmia," or irregular heartbeat, according to a statement from his spokeswoman, Lea Anne McBride.
Cheney is scheduled to have a stress test on a treadmill in the fall as part of a comprehensive cardiac evaluation.
Dr. Bernadette Aulivola, a vascular surgeon at Loyola University Health System in suburban Chicago, said it was a good sign that Cheney's defibrillator had not been activated since it was last checked.
"If he had had an irregular heartbeat, the ICD would have kicked in," Aulivola said.
The physical did not slow Cheney's pace.
The vice president's schedule for the rest of Saturday: flying to Florida to watch the scuttled shuttle Discovery launch from the Kennedy Space Center and then attending the Pepsi 400 at the Daytona International Speedway.
In addition to the four heart attacks, the vice president has had quadruple bypass surgery and two artery-clearing angioplasties.
In September, he underwent six hours of surgery on his legs to repair a kind of aneurysm, a ballooning weak spot in an artery that can burst if left untreated. Cheney had flexible stent grafts put in his knee arteries. The stents, when fully opened, keep the rushing blood from touching the weakened artery walls.
"The stent grafts used to treat the popliteal artery aneurysms are wide open," McBride said.
That they are open means the blood flow to the grafts is normal and haven't clogged, Aulivola said. Patients who have had this kind of surgery typically are given intermittent checkups, often once a year, Aulivola said.
She said the upcoming stress test, which will determine if the blood flow to Cheney's heart is adequate, is unrelated to the vice president's aneurysms.
Cheney was carrying a newspaper and was accompanied by his security detail when he enter the George Washington University Medical Center at about 7 a.m. He left less than three hours later, walking to his motorcade and waving at cameras but saying nothing.