What benefit does the implantable cardioverter-defibrillator give to patients who have had a cardiac arrest or heart attack?

Prevent recurrence: Depending on the reason for cardiac arrest, an automatic implantable defibrillator can be very effective in preventing a second cardiac arrest in the future.

It may prevent death: Implantable cardioverter-defibrillators (icds) are used to treat ventricular tachycardia or ventricular fibrillation, which if untreated, may cause a fatal cardiac arrest. Icds can often quickly treat these conditions before permanent brain or heart damage can be done. Icds are not used to treat or prevent heart attacks, which are a "plumbing" issue.