In a chilling episode of “Homeland” last year, a terrorist killed the vice president with a fiendishly clever weapon: a remote-control device that attacked the computerized defibrillator implanted in his chest.

For former Vice President Dick Cheney, it was all too realistic.

Mr. Cheney, who had heart disease for decades before receiving a transplant last year, had such an implant to regulate his heart rate and shock his heart back into life, if necessary. The defibrillator could be reprogrammed wirelessly from a short distance away. In 2007, he had the wireless feature disabled.

About the “Homeland” scenario, Mr. Cheney said on the Oct. 20 episode of “60 Minutes”: “I found it credible. It was an accurate portrayal of what was possible.”

But was it really? Medical experts say the answers are surprisingly complicated.

Mr. Cheney’s cardiologist, Dr. Jonathan Reiner of George Washington University, said in the “60 Minutes” interview that he agreed with his patient.