What is an ICD?

ICD stands for implantable cardioverter defibrillator. This is a small electrical device which, rather like a pacemaker, is put into the body to detect and treat life-threatening abnormal heart rhythms.

But whereas the pacemaker is primarily designed to treat slow heart rhythms and atrial fibrillation, the ICD corrects heart rates that are fast (ventricular tachycardia and ventricular fibrillation) or slow. These are rhythms that originate in the lower chambers of the heart: ventricular tachycardia (VT) and ventricular fibrillation (VF).

What does an ICD do?

The ICD

• monitors the heart's rhythm
• senses and detects rapid or slow heart rhythms
• treats abnormal rhythms with electrical therapy
• stores data for review.

Its actions include:

• bradycardia pacing – low-energy electrical pulses when the heart rate is too slow
• anti-tachycardia pacing (ATP) – a series of small, rapid electrical pulses to interrupt a rapid, abnormal heart rate and return the heart to its normal rhythm
• cardioversion – a shock impulse to correct VT
• defibrillation – a stronger shock impulse to correct VF. This has been described as feeling like a kick in the chest.

When are ICDs needed?

ICDs are designed for people who have experienced or are deemed to be at high risk of abnormal fast rhythms that originate in the ventricles (lower chambers of the heart) rather than in the heart's natural pacemaker – the sino-atrial node in the atria (upper chambers).

Will an ICD cure heart disease?

It is important to remember that the ICD does not cure the underlying disease that causes the arrhythmia (abnormal heart rhythm). But the device continuously monitors the heart's rhythm so that it can deliver the appropriate therapy.

ICD's have improved outcomes and reduced the incidence of sudden death. Most ICD patients perceive the device as a great source of security, one that quite literally gives them a second chance at life.

ICD support groups

At first, it can be hard to cope with the rapid changes that have taken place in their lives and the emotions that follow. In time, most people develop a very positive attitude to the ICD device and enjoy a full and active life.

At Sydney's North Shore Hospital, the Cardiac Rehabilitation and ICD Support Groups can play a valuable role in a patient's recovery. Both are widely recognised support and resource networks for ICD clients, hospitals and health professionals throughout Australia.

Group meetings are held four times a year and are always well attended. A wide range of guest speakers have covered a variety of topics.

These resource groups also have a variety of educational resources available, including an action plan. This gives simple guidelines about what to do if you receive ICD shock therapy.

If you would like further information about the ICD support group please contact:

Ann Kirkness
Clinical Nurse Consultant
North Shore Cardiovascular Education Centre
Ph: +61 2 9926 6560

This information was first published in You and Your Heart - an education booklet for patients, families and friends. © 2006 Northern Sydney Central Coast Area Health Service