Former Vice President Dick Cheney recently revealed that the defibrillator implanted in his heart was altered to prevent terrorist attacks, reports Medical Xpress.

Two years ago, Cheney had a heart transplant.  Cheney had five heart attacks that required multiple angioplasties and catheterizations, along with a quadruple bypass operation. His first heart attack took place more than 35 years ago.

Prior to his heart transplant, he underwent a series of procedures to keep him alive despite his cardiac problems.  One of these procedures was an implanted defibrillator.  However, the defibrillator normally comes with a wireless function.  In consultation with his cardiologist Jonathan Reiner, Cheney had the wireless function disabled.  If it remained active, it was possible that terrorists could hack into the device and trigger a fatal shock to his heart.  Cheney found the possibility of a threat credible and agreed to the modification.

During a “60 Minutes” interview scheduled to air on Sunday, Cheney told Dr. Sanjay Gupta that an episode of “Homeland,” in a which a terrorist kills the vice president by hacking into his cardiac implant, scared him.

“Because I know from the experience we had and the necessity for adjusting my own device that it was an accurate portrayal of what was possible,” Cheney said.

According to the National Heart, Lung, and Blood Institute, an implantable cardioverter defibrillator (ICD) is a small device that’s placed in the chest or abdomen. Doctors use the device to help treat irregular heartbeats called arrhythmias.  It uses electrical pulses or shocks to help control life-threatening arrhythmias, especially those that can cause sudden cardiac arrest.  Arrhythmias can prevent the heart from pumping blood well.  If not treated, the person can pass out and die within minutes.  Defibrillation provides the immediate treatment.

Cheney played a critical role in the Bush Administration’s War on Terror, influential in the wars in Iraq and Afghanistan, as well as the development of terrorist surveillance programs, reports ABC News.  He denied that the stress he endured while serving as vice president during all eight years of the Bush administration from 2001 to 2009 caused or exacerbated his health concerns.

Cheney was aware of numerous studies that showed a significant link between severe heart disease and memory loss, depression and hampered decision-making.  However, Cheney was not worried about the impact, considering his health and his professional life as separate areas.  In contrast, Dr. Reiner was regularly concerned about the connection between the stress of his job and Cheney’s health.

For example, a blood test result seen on the very morning of 9/11 showed a surge of potassium in the vice president’s blood, which could mean a potentially fatal condition known as hyperkalemia.  As Dr. Reiner watched television coverage of the attacks on New York and the Pentagon and the crash of a hijacked plane in Pennsylvania, he felt certain that the vice president was going to die from the condition.