Washington ? 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 was in 1978, when he was 37, and the fourth was 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.

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 an aneurysm.