Introduction

Heart rhythm problems (arrhythmia) occur when the electrical impulses produced by your heart that coordinate heartbeat do not function properly, causing your heart to beat too quickly, too slowly, or irregularly. Some heart arrhythmias are harmless, though some types, such as ventricular tachycardia (fast heart rates), are serious and even life threatening.

What is ICD implantation

The ICD is a device that is implanted in a manner similar to a pacemaker. It is about the size of a pager and performs several functions. It monitors your heart rhythm continuously and paces your heart when the rate is too slow.

Who is it for

If you have been found to be at recurring risk of heart rhythm problems such as ventricular tachycardia (when the heart beats at a dangerously fast pace) or ventricular fibrillation (when the heartbeat is both fast and irregular), an automatic implantable cardioverter defibrillator (AICD) may be your best insurance against cardiac arrest.

How is it done

As the name suggests, the AICD has two primary functions:
• Cardioversion
When the AICD detects ventricular tachycardia, it delivers a mild electrical shock that converts the fast heartbeat into a normal heartbeat.
• Defibrillation
Sometimes cardioversion fails and ventricular tachycardia either worsens or progresses into ventricular fibrillation. At other times, ventricular fibrillation develops spontaneously.

When the AICD detects either of these life-threatening rhythm abnormalities, it delivers a strong
electrical shock that defibrillates or resets your heart to start beating normally.

The procedure is similar to a pacemaker implantation. The procedure is done under local anesthesia. A skin incision is made below the collarbone, usually on the left side. A pocket to contain the ICD is then created. The vein behind the collarbone is punctured and via this vein, the leads are advanced to the designated heart chambers. The leads are then connected to the pulse generator and the whole system placed within the created pocket. The skin incision is then closed with absorbable sutures. The patient is then usually heavily sedated and the ICD system is tested to ensure it detects and treats the life threatening rhythm. It takes approximately 1 to 2 hours to implant the ICD. Most patients are discharged from the hospital within 24 to 48 hours after ICD implantation.

Risks

The risk of implantation is estimated to be about 1%, including excessive bleeding, pneumothorax (air leak from the lung), cardiac perforation, long term risk of infection and device malfunction. Recent studies have confirmed the usefulness of the ICD in addition to optimal medical therapy. The ICD protects these patients at risk from premature deaths due to life threatening heart rhythm.

Aftercare

A patient will need to carry an ICD identification card to indicate the type of ICD that has been implanted. Devices such as anti-theft systems in stores, airport screening devices and metal detectors may interfere with the device’s performance although these occurrences are rare.

Microwave ovens and other common household appliances usually do not interfere with the function of these devices. However, mobile phones should be placed more than 15 cm from the ICD to prevent possible interferenced.

A patient with and ICD implanted should always inform his doctor or dentist before any going for procedure which utilises medical or electronic devices for fear of potential interferences.