What is a cardiac implantable electronic device?
A cardiac implantable electronic device is a medical tool that regulates heart rhythms. Specialized heart doctors called electrophysiologists place the cardiac implantable device in the heart during a surgery or minimally invasive procedure. For children and adults born with heart disease, pediatric electrophysiologists are specially trained to treat these patients using pacemakers and defibrillators. At Children’s Hospital Colorado, pediatric- and adult-trained specialists in the Heart Institute’s Pediatric and Adult Congenital Electrophysiology Program treat patients with a wide range of heart rhythm problems from birth throughout adulthood.
Types of cardiac implantable electronic devices
There are different kinds of cardiac devices, including pacemakers and implantable cardioverter defibrillators (ICDs). A pacemaker helps control heart rhythms that are too slow, while an ICD helps control abnormal heart rhythms from the bottom chambers of the heart that are too fast.
Pacemakers and ICDs have three components:
- Leads: specialized wires that carry energy from the device to the heart
- Electrodes: sensors on the end of each lead that sense the patient’s heartbeat and deliver the electrical pulses from the pulse generator
- Pulse generator (pacemaker or ICD): the device containing the battery pack and computer that control the electrical pulses
How are pacemakers and implantable cardioverter defibrillators (ICDs) implanted?
Pacemakers and ICDs can be implanted in a few ways.
Endocardial (transvenous, or through the veins) implantation
Leads are inserted into the patient’s veins leading to the heart, ultimately attaching to the inside of the heart. The device is often placed in the patient’s chest below the collarbone, or it might be placed in their armpit. This procedure is for traditional pacemakers and is used for older children, adolescents and adults.
Epicardial (on the epicardium, or outer surface of the heart) implantation
Unlike with endocardial devices, the device is inserted through the abdomen at the bottom of the patient’s chest. Instead of running the leads through the veins to the inside of the heart, they are attached to the outside. This method is usually used for younger children and babies or children or adults with abnormal blood vessel connections as a part of their congenital heart disease.
Leadless cardiac devices are implanted through the veins in a patient’s leg. The device is smaller than a traditional pacemaker — about the size of a pill — and sits completely inside the heart. The device delivers small electrical impulses to stimulate the heart without needing an additional implant under the skin. This method is used for patients experiencing bradycardia (i.e., slow heartbeat) who don’t need frequent pacing.
Subcutaneous ICDs are implanted under the skin in the left armpit with a lead just underneath the skin on the chest. The lead does not travel in the veins, and it does not touch the heart. This can make the removal of the lead easier, if needed. Subcutaneous ICDs monitor the heart and send an electrical pulse if it detects an abnormal heart rhythm, but it doesn’t regulate or maintain a normal heart rate. This method is usually used for patients who don’t need pacing.
How do pacemakers work?
The pacemaker constantly monitors the patient’s heart rate and only sends electrical signals to the heart when needed. If the heart rate is not fast enough, the pacemaker sends small electrical pulses to the heart to keep it beating properly. The pulse starts in the battery and goes through the leads to the heart muscle.
For one to three months after the pacemaker is put in, the heart needs a strong electric signal from the pacemaker to make it beat properly. After about six to eight weeks, the heart doesn’t need as strong of a signal, so the amount of electricity running through the leads to the heart is turned down during a visit with the cardiologist.
How do ICDs work?
ICDs differ from pacemakers because they help patients with abnormally fast heart rhythms. ICDs help prevent sudden death from an abnormal heartbeat from the heart’s lower chambers (ventricles), such as cardiac arrest or a pediatric cardiac arrhythmia.
ICDs work by monitoring the patient’s heart rate. If the heart rate is too fast and from the wrong chamber, the defibrillator will send energy to the heart to re-establish a normal rhythm.
How long do pacemakers and ICDs last?
Pacemaker or ICD batteries will generally last five to seven years. How long the device lasts depends on a few things:
- The number of functions it’s performing
- How much it is used
- How much energy it takes to stimulate the heart
What to expect during cardiac device implantation
Endocardial implant procedures
If you need an endocardial system for the cardiac device (i.e., when leads attach inside the heart), the wires are inserted into a large vein below the collarbone and guided into the heart. The pacemaker is put under the skin on the chest, just under the collarbone, or under an arm near the armpit.
At Children’s Colorado, this procedure takes place in our state-of-the-art Electrophysiology Lab by a pediatric electrophysiology doctor and typically takes 2.5 to 3.5 hours. After the procedure, patients need to stay one night in the hospital and can go home the following day.
Epicardial implant surgeries
If you need an epicardial system (i.e., when leads attach to the outside of the heart), the battery is placed underneath the lower part of the breastbone under the chest or abdominal muscle.
Depending on the number of leads needed, a cardiac surgeon will make an incision through the breastbone or just below it to access the heart, then place leads on the atrium (top chambers of the heart), ventricle (lower chambers) or both. The procedure typically takes two to four hours, and patients need to remain in the hospital for two to four days after the procedure.
All procedures are completed under general cardiac anesthesia, so you will not remember the procedure. Any mild discomfort felt afterward can be treated with oral pain medications.
What to expect after cardiac device implantation
The recovery time for cardiac device implantation varies based on the type of implant. For endocardial systems, patients typically return to school or work and daily activities in six to seven days. For epicardial systems, full recovery and return to competitive athletics usually takes six weeks.
After an implantation procedure at Children’s Colorado, your medical team will provide you with proper care and follow-up instructions.
Precautions after a cardiac device procedure or surgery
We want you to have as few activity restrictions as possible after cardiac device implantation. However, there are several environmental precautions to keep in mind:
- Anything with a very large magnet should be kept at least 6 inches away from a pacemaker.
- Avoid equipment with high-energy electrical fields like chain saws, welding machines and high-output radio transmitters.
Microwave ovens, airport metal detectors, cell phones and X-rays are safe to use after receiving a pacemaker or defibrillator.
Some cardiac devices have movement restrictions for six weeks after implantation. These restrictions might include:
- No lifting of the arm over the head on the side where the device was placed for six weeks. This means any movement where the elbow goes above the shoulder.
- No throwing, bowling or backpack straps on the restricted arm for six weeks. When getting dressed, put the restricted arm in the shirt sleeves first.
- No lifting more than 10 pounds for six weeks.
After cardiac device implantation surgery, the patient gets their incision checked at both one and two weeks following their procedure, and they have a follow-up appointment with their electrophysiologist at six weeks. Follow-up appointments are usually done from your home with a remote heart monitor, and there are yearly in-person cardiology visits.
Why choose us for pediatric cardiac device implantation?
The electrophysiology team at the Heart Institute is highly specialized and trained in all cardiac device implant procedures. We are internationally recognized for treating abnormal heart rhythms and provide top heart rhythm care for infants, children, teens and adults. We also offer a comprehensive, multidisciplinary lead removal, extraction and management program for children and adults with congenital heart disease in case one needs to be removed or replaced at any time during the life of the cardiac device.
Congenital and childhood heart rhythm problems require specialized, lifetime care from a team of pediatric cardiology experts. Our electrophysiology team has specialized training to treat pediatric heart rhythm conditions from before birth through adulthood. They see thousands of patients and perform hundreds of interventions each year for patients from around Colorado and nearby states like Wyoming, Montana, New Mexico and Kansas. The high number of implantations we perform proves our experience and expertise with the complete spectrum of heart rhythm conditions, from the common to the complex.
Care from multiple specialists
Our multidisciplinary team works together to provide the best personalized care for each of their patients. After a cardiac device procedure at Children’s Colorado, patients can return to their favorite activities with confidence knowing that they have individualized recovery and follow-up plans from their care team.