Washington, D.C. ? Vice President Dick Cheney’s routine checkup Friday revealed no new blockages in his heart, but doctors said he needs a new battery for a special pacemaker he has in his chest, a spokeswoman said.

The battery in his implanted cardiac defibrillator is reaching its limit, said Megan McGinn, deputy press secretary for the vice president. She said doctors must replace the entire device to replace the battery, and that the surgery will be scheduled this summer at a convenient time for the vice president.

Cheney underwent his annual physical, which included a stress test, at the George Washington University Medical Faculty Associates near George Washington University Hospital.

Doctors also checked Cheney’s cardiac defibrillator, which was implanted in June 2001 to shock his heart if he an irregular heartbeat.

Cheney has had four heart attacks, quadruple bypass surgery, two artery-clearing angioplasties and an operation to implant the defibrillator.