Medical Health Encyclopedia

Implantable cardioverter-defibrillator

Many episodes of VT or VF, however, occur outside hospitals and people without ICDs often die because defibrillation is not immediately available.

Candidates for ICDs are people at risk of sudden death, including:

• those who have survived a cardiac arrest due to VF not triggered by a recent heart attack
• those with life-threatening episodes of VT
• survivors of a heart attack with weakened pumping function
• those who have structural defects of the heart muscle, such as dilated cardiomyopathy and hypertrophic cardiomyopathy, especially when unexplained fainting episodes have occurred
• people with a reduced pumping function of the heart, often assessed as a left ventricular ejection fraction (LVEF) of 35% or less

Occasionally, an electrophysiological study (EPS) is required to make the decision about ICD implantation. The EPS is a special test conducted by a cardiologist with a specialization in arrhythmias. The EPS measures how much the heart is at risk for an event that could prove fatal.

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What to expect after ICD implantation

The recovery time after the ICD implantation is quite short. Hospital stays are rarely longer than 1 day; and patients quickly return to prior activity levels. Full recovery of activity can be expected in about 4 to 6 weeks.

You will be discharged from the hospital with a wallet card listing the specifications of your ICD and providing contact information for emergencies. This wallet card should always be with you when you go out.

You will need to make regular visits to the doctor so the ICD can be monitored. The monitoring shows whether the device is sensing the heartbeat properly, how many shocks have been delivered, and how much power is left in the batteries. The ICD batteries are designed to last 5 to 8 years. When they are about to run down, the ICD generator must be replaced. This requires minor surgery.