Vice President Dick Cheney got a clean bill of health from doctors at George Washington University Hospital who were conducting a routine exam on the condition of his electronic pacemaker.

In fact, not once has the pacemaker, called an implantable cardioverter defibrillator, been set off to correct an irregular heartbeat since it was implanted last June.

"After his routine checkup, the vice president was told by his doctor that all the news was very good," Cheney adviser Mary Matalin said Friday. 

Cheney's cardiologist, Richard S. Reiner, "noted that the vice president's ICD neither detected nor treated any arrhythmia," she added. 

Cheney, 61, has had four heart attacks, his first at age 39.

He had the 3-ounce, pager-sized contraption installed last June following two procedures to unblock clogged arteries. In one of those procedures, shortly after becoming vice president, Cheney had a stent placed in an artery to prop it open. 

Before the exam, Matalin said the procedure was a "routine, semiannual cardiovascular checkup to include a physical exam, an EKG, an echo cardiogram and a stress test."

About 150,000 Americans have the same battery-operated device, which regulates the heart rate, speeding it up or slowing it down as needed.  The doctors electronically scanned the pacemaking device to make sure it is working and to see if it has adjusted to Cheney's heartbeat. It is a noninvasive procedure

Cheney arrived at his doctor's office at George Washington University Medical Center around 7 a.m. Friday. He was there for approximately two hours, departed without comment, and immediately went back to work.

The Associated Press contributed to this report.