Find A Doctor

Automated Implantable Cardioverter Defibrillator (AICD)


What is an AICD? 

AICD is a device combining a cardioverter and a defibrillator into one implantable unit. It is thus a small battery-powered electrical impulse generator that is implanted in patients who are at risk of sudden cardiac death due to fast arrythmias.

The ICD is designed to deliver two levels of electrical energy: a low energy shock that can convert a beating heart that is in an abnormal rhythm back to a normal heartbeat, and a high energy shock that is delivered only if the arrhythmia is so severe that the heart is only quivering instead of beating.

Why do I need an AICD?

AICDs are advised if you are at risk for potentially fatal ventricular arrhythmias (an abnormal rhythm from the lower heart chambers, which can cause your heart to pump less effectively).


Arrhythmias can cause problems with contractions of your heart chambers by:

  • Not allowing the chambers to fill with an adequate amount of blood because the electrical signal is causing your heart to pump too fast.
  • Not allowing a sufficient amount of blood to be pumped out to your body because the electrical signal is causing your heart to pump too slowly or too irregularly.

What is the difference between a pacemaker and an AICD?


If your heart rhythm is too slow and is not treatable with medications, then a pacemaker would be needed. A pacemaker keeps your heart beating at the proper rate and not too slow. However, It is not shocking people all the time as it will only be activated if it is needed.


An implanted defibrillator is a bigger device. It prevents death from cardiac arrest. The device shocks your heart if needed for a life-threatening rhythm disturbance from the ventricles of your heart. As a pacemaker is built into it, AICD also has the capability of stimulating the heart like a pacemaker.