Implantable Cardioverter Defibrillators (ICDs) in Children
An Implantable cardioverter defibrillator (ICD) is a special type of cardiac device that can recognize abnormal heart rhythms in the bottom part of the heart and deliver therapy if needed to restore the heart to a normal rhythm.
It has 2 components: lead(s), which is a specialized wire to deliver energy from the ICD to the heart muscle and the generator (battery pack)
ICDs can function in a couple of ways:
- ICD’s use the lead to analyze heart rates that are too fast and identify if this rhythm may be life threatening, such as ventricular tachycardia (VT) or ventricular fibrillation (VF).
- If the ICD identifies an abnormal rhythm (arrhythmia) it attempts to pace the heart into an organized normal rhythm.
- If unable to convert (normalize) the rhythm by pacing, the ICD will deliver energy by shocking the heart, to convert it into an organized normal rhythm.
- If heart rate is too slow, it can function like a pacemaker in certain ICDs.
ICD have become the treatment choice for patients who are at a high risk of sudden cardiac death. In primary prevention, patient has been identified to be at high risk but has not yet experienced a sudden cardiac event compared to secondary prevention for a patient who has experienced a sudden cardiac arrest.
ICD therapy is indicated in patients who are survivors of cardiac arrest due to ventricular fibrillation (VF) or hemodynamically unstable sustained VT after evaluation to define the cause of the event and to exclude any reversible causes. Other reasons to implant an ICD can include:
- patients with structural heart disease and sustained VT
- patients who have passed out where the cause is identified to be an abnormal heart rhythm.
- primary prevention for patients with who are high risk of sudden cardiac death related to a diagnosis of cardiac channelopathies, structural congenital heart disease, hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and severe left ventricular dysfunction in the presence of ventricular arrhythmias and other causes of ventricular arrhythmias.
The decision to implant an ICD should be discussed with your cardiology team.
On the Inside:
ICDs can be implanted in multiple basic ways in children and adolescents.
The systems can be:
- epicardial (leads attached to the outside of the heart)
- transvenous (leads inside the veins leading to the heart)
With transvenous or epicardial placement, the leads can be attached to the top chamber of the heart (atrium) or the bottom chamber of the heart (ventricle) or both. Sometimes leads are placed on both ventricles.
A subcutaneous ICD is a newer technology where the leads are implanted under your skin instead of inside your veins or attached to the outside of the heart. This allows for easier removal of the leads if this becomes necessary.
Recovery from implantation of an ICD varies, depending on the child and whether or not other heart surgery was performed at the time. Typically, a child leaves the hospital one to three days after implantation of an ICD if this is the only surgery performed at the time. Restriction of arm movement may be necessary for certain types of procedures.
The type of ICD used is based on your diagnosis and specific needs of the device.
Activity restrictions or precautions may be recommended depending on your child’s heart disease and type of ICD. Your cardiologist will review these recommendations with you.
Patients with ICDs will require future procedures related to the ICD generator (battery pack) longevity or battery life. The ICD generator (battery pack) typically last 5-10 years.
The lead(s) only need to be changed if they stop functioning. In some instances, the lead has to be removed and replaced.
Routine visits with the cardiologist and/or electrophysiologist provide the best care for the ICD. At these appointments the pacemaker/ICD leads and battery are tested.
Today’s advanced technology provides a way to check an ICD at home (remote monitoring). A monitor will be set up by your child’s doctor or pacemaker clinic if it is part of their plan of care.
The monitor will collect information from the ICD and send it securely over the phone system and internet to the pacemaker clinic. Your child’s doctor will determine how often and when transmissions are to be sent using the monitor versus when you need to come to the hospital to have the ICD checked in person.