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.

Short-term restrictions

You'll likely be able to return to normal activities such as exercise, work and sex soon after you recover from surgery. During the first four weeks following surgery, however, your doctor may ask you to refrain from:

• Vigorous above-the-shoulder activities or exercises, including golf, tennis, swimming, bicycling, bowling or vacuuming
• Lifting anything weighing more than 5 pounds
• Playing contact sports
• Strenuous exercise programs

If you have an implantable cardioverter-defibrillator to treat ventricular arrhythmia, driving a vehicle presents a special challenge. The combination of arrhythmia and defibrillation may cause fainting, which could be dangerous if you're driving. The American Heart Association's guidelines discourage driving during the first six months after this surgery if the device was implanted due to a previous cardiac arrest or ventricular arrhythmia. If you experience no shocks during this period, you may resume driving. But if you later experience a shock, with or without fainting, avoid driving until you've been shock-free for another six months.

If you have an implantable cardioverter-defibrillator but have no history of life-threatening arrhythmias, you can consider driving one month after surgery with your doctor's approval, if you've had no shocks. Most states won't grant commercial driver's licenses to anyone who has an implantable cardioverter-defibrillator.

Long-term precautions

ICD malfunction due to interference from electronics and security systems is rare. Still, take precautions with the following:

• Cellular phones. It's safe to talk on a cell phone, but avoid placing your cell phone within six inches of your ICD implantation site when the phone is turned on. Although unlikely, your ICD could misinterpret a cell phone's signal as a heartbeat and withhold pacing, producing symptoms such as sudden fatigue.
• Security systems. After surgery you'll receive a card that says you have an ICD. Show your card to airport personnel because the ICD may set off airport security alarms. A word of warning: Hand-held metal detectors often contain a magnet that may interfere with your ICD. Ask the security personnel to limit scanning with such a device to less than 30 seconds over the site of your ICD or make a request for a search by hand.
• Medical equipment. If a doctor is considering any medical procedure that involves intensive exposure to electromagnetic energy, such as magnetic resonance imaging (MRI) or magnetic resonance angiography (MRA), tell him or her that you have an ICD.
• Power-generating equipment. Stand at least two feet from welding equipment, high-voltage transformers or motor-generator systems. If you work around such equipment, your doctor can arrange a test in your workplace to determine whether it affects your ICD.

Devices that present little or no risk to ICD function include microwave ovens, televisions and remote controls, radios, toasters, electric blankets, electric shavers and electric drills.

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.

What about recalls of ICDs?

You may have heard about the recall of some models of ICDs. If you have any questions concerning your ICD, call your doctor. ICDs have been proved to be very safe, and malfunctions are uncommon.

Questions to ask your doctor about ICD recalls

• Is your device affected by a recall?
• Does your ICD need to be replaced?
• How frequently should your ICD be checked, and what sort of checks should be done?
• Is there anything you can check on your ICD from home?
• Should you visit your doctor?

What are the long-term effects?

If you're at high risk of ventricular tachycardia and ventricular fibrillation, an ICD may be your best defense against cardiac arrest. Once you have an ICD, it's likely you'll need to keep it for life. Although the electrical shocks may be unsettling, they're evidence that the ICD is effectively treating your heart-rhythm problem and protecting you from sudden death. Talk to your doctor about how to best care for your ICD.