Why did my doctor order an implantable cardioverter defibrillator for me?

See Below: Please ask your cardiologist to fully explain your individual indications for the implanted defibrillator. In general, a icd is implanted because the patient has a dangerous, life-threathening arrhythmia such as ventricular tachycardia or ventricular fibrillation. The shock(s) delivered by the icd can return the heart to a normal rhythm in an instance of deadly arrhythmia.

ICD: You must be at risk for an arrhythmia called ventricular fibrillation that the icd is designed to detect and shock to avoid sudden death.