Implantable cardioverter-defibrillator: After your ICD is implanted

You've had an implantable cardioverter-defibrillator inserted to reduce your chance of sudden cardiac death. You can help ensure that your implantable cardioverter-defibrillator is working properly by following a few easy tips.

Battery life

The lithium battery in your implantable cardioverter-defibrillator has an effective life of up to seven years. During your regular checkups, which occur every three to six months, your doctor or nurse assesses the remaining battery life. When the battery is nearing exhaustion, your old pulse generator is replaced with a new one during an outpatient procedure that's relatively minor compared with your initial surgery.

How do you know if your ICD is working?

When you experience a rapid heartbeat, the leads transmit signals to the ICD to begin sending electrical pulses which can occur in a range depending on your heartbeat:

• Low-energy pacing therapy. You may feel either nothing or a painless fluttering in your chest.
• Cardioversion therapy. A higher energy shock is delivered. You might feel as if you're being thumped in the chest.
• Defibrillation therapy. This is the strongest form of electrical therapy. During this therapy you may feel as if you're being kicked in the chest. It may knock you off your feet. The pain from this therapy typically lasts only a second. There should be no discomfort after the shock is over.

Usually, only one shock is needed to restore a normal heartbeat. Sometimes, however, you may experience two or more such shocks during a 24-hour period. Frequent shocks in a short time period are known as "ICD storms," and they may understandably cause anxiety. If you experience ICD storms, you should seek emergency care to see if your ICD is malfunctioning or if you have a problem that's making your heart particularly irritable. If necessary, the ICD can be adjusted. Additional medications may be needed to stabilize your heart rhythm and decrease the chance of an ICD shock.

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