Many parents have questions about implantable cardioverter defibrillators (ICDs) — what they do and how they work. Here are some common questions and answers.
- Will an ICD cure my child's heart rhythm problem?
- Is an ICD the right treatment for all rhythm disturbances?
- Do shocks from an ICD hurt?
- If I touch my child during an ICD shock, what will happen?
- After the device is implanted, can my child return to life as it was before?
- Where will the defibrillator be placed?
- Is the implant procedure an open-heart operation?
- How is the ICD powered?
- How often are ICD check-ups performed?
- Can children with defibrillators go near microwave ovens?
- Is there any equipment children with defibrillators should avoid?
No, the defibrillator won't cure a heart rhythm problem. Cure means to completely and permanently eliminate the condition. A defibrillator is most commonly used as part of a child's treatment. Each time your child's heart rhythm changes for the worse, the defibrillator responds to treat the problem. Many doctors use defibrillators along with medications called antiarrhythmics. The medication helps keep the heart rhythm from racing, while defibrillators act as a "failsafe" device in case the heart rate speeds dangerously, despite medication.
In some cases, an electrophysiogist can cure a rhythm disturbance, sometimes by performing a procedure called ablation.
No, defibrillators treat serious rhythm problems that arise in the lower chambers of the heart, called the ventricles. Medication alone often can provide good heart rhythm control. But when a child's symptoms worsen or when the problem is persistent or potentially dangerous, you child's doctor may perform an electrophysiology (EP) study to learn more about the rhythm and identify treatments in addition to medication. In some cases, when the solution is clear, an electrophysiology study isn't necessary. If a defibrillator is an option, your child's doctor will discuss it with you.
Most patients who have received shocks from defibrillators don't describe the sensation as "pain." Patients describe the shocks as startling, jolting and unsettling — and it's easy to understand why. The defibrillator delivers a shock to prevent a dangerously fast heart rhythm. An abnormal rhythm must occur before the device responds. A racing heart rhythm may cause dizziness, lightheadedness, palpitations, an "about-to-faint" feeling — and then, a shock from the defibrillator triggers a normal rhythm. The jolt is a powerful one, selected specifically to control the heart without delay.
Nothing will happen to you. A shock from an ICD is different from a shock given externally, such as those given by paramedics or emergency room workers with "paddles" on the chest, called defibrillation. When we defibrillate someone externally we use a great deal of energy to be certain that it will travel from the exterior chest to the heart and still have enough power to do the job.
An ICD shocks the heart directly, through wiring connected to the heart, and uses far less energy. The energy that escapes to the surface, where you might touch your child, is very difficult to detect and completely harmless.
In many cases, life can begin to return to normal after an ICD is implanted. Most children return to school and their usual activities including physical activity, such as sports and exercise, once the doctor determines that this is safe. On occasion, the type of exercise or sport may be modified. Your child's doctor will make recommendations and discuss this with you. How long it will take, of course, depends on the individual patient and other medical problems he or she may have.
In the past, when ICDs were much larger, they were too big to implant anywhere but in the abdomen. Now that they much smaller, doctors usually implant them in the chest — a little below the clavicle, or collarbone, on either the right or the left side of the chest. Patients often can feel and see the outline of the device under the skin. Your child's doctor will decide the best location for your child's ICD.
No. Implanting an ICD is much simpler than it was a few years ago and often takes less than three to four hours. The procedure is usually performed in the pediatric electrophysiology lab. Your child will receive general anesthesia for this procedure and will be asleep from start to finish The incision is usually a small one — three to four inches wide — and is horizontal on the chest.
After the ICD is in place and the incision closed, a bandage will be applied to protect the site. Your child will go to the recovery room for a few hours before returning to the hospital bed for an overnight stay. In most cases, you may join your child in the recovery area. Most patients notice some soreness once the local anesthetic has worn away that usually lasts about a week. Your child's doctor and nurses will discuss medications to take at home to help with pain control. Doctors advise patients with new ICDs to avoid getting the site wet until the skin has healed, usually a couple of weeks.
ICDs are powered by batteries and last for five years or more. An ICD that delivers many shocks will wear out sooner than one rarely activated. Checking the battery is an important part of your child's routine follow-up. A clinic visit to the electrophysiologist or cardiologist usually includes a device check-up. A piece of equipment called a programmer is used to "ask" the ICD to show its battery voltage and settings, as well as any rhythm disturbances it has detected and therapy it delivered since the last visit.
Long before the battery is ready to expire and long before the performance of the ICD changes in any way, a check-up will show that the time is approaching to consider a replacement ICD. At that point, a brief hospital stay is arranged — typically no more than one or two days — to remove the old ICD and replace it with a new one. Replacement procedures often are simpler than original implantations and take less time.
Doctors vary in their opinions about the frequency of ICD check-ups. Some prefer to see patients every two months or more often when they feel the heart rhythm needs close observation. Others ask patients to return every four or six months, especially when rhythms are quite stable.
Yes. A number of years ago, when ICDs and microwave ovens were made very differently, some reacted badly in the presence of old-style microwave ovens. As a result, ICDs were modified and are no longer affected by microwave ovens.
Doctors advise their ICD patients to avoid the following:
- Very powerful magnets — such as those you might find in a junkyard used to lift discarded automobiles, or those contained within the cases of powerful stereo speakers — should be avoided. (Smaller, weaker magnets, like those used to hold notes on a refrigerator, or those found in telephone receivers, pose no difficulty at all.)
- The very powerful electromagnetic field generated by the equipment used for magnetic resonance imaging (MRI) should be avoided.
- The field very close to an automobile ignition system also should be avoided. The main concern is that a very strong electromagnetic field temporarily deactivates the ICD. This occurs only when the patient is in the field, returning the ICD to full function as soon as the patient is distant from the magnetism. Even a brief suspension in the operation of the ICD should be avoided.