Studies

• The Federal Government has ruled that an electrical shock can become dangerous to a defibrillator at 10 to 50 joules (the joule count is variable because danger is dependent upon the source of the shock, the length of the shock and the shock current). However, modern defibrillators are designed to withstand electric shock, and modern stun guns are made with defibrillators in mind, usually delivering less than a single joule per shot.
  
  

Controversy

• Not everyone is convinced that stun guns are safe, even when used on a healthy heart. Stun gun manufacturers advise that their product not be used against children, the elderly or people with defibrillators, among others. However, there are examples of police ignoring this vital safety advice, which sometimes results in deaths.
  
  

Conflicting Information

• Enough tests have been performed to know that a modern stun gun won't generally affect the heart; however, in 4 percent to 10 percent of test cases in a Canadian Medical Association study, exceptions were recorded. When the heart is affected, an attached defibrillator can be affected as well.