Frequently Asked Questions about Pacemakers and Implantable Cardioverter Defibrillators
Peace of mind is important and the pediatric cardiology specialists at the CHOC Heart Institute are with patients and their families every step of the way. We have put together the following frequently asked questions about kids and defibrillators to help patients and families better understand the devices and how they work.
What is a pacemaker?
A pacemaker is a life-saving medical device composed of three parts: a pulse generator, one or more leads (wires) and an electrode on each lead. A pacemaker signals the heart to beat when the heartbeat is too slow or irregular.
A pulse generator is a small metal case that contains electronic circuitry with a small computer and a battery that regulate the impulses sent to the heart. The lead (or leads) is an insulated wire that is connected to the pulse generator on one end, with the other end placed inside one of the heart’s chambers. The lead is almost always placed so that it runs through a large vein in the chest that goes directly to the heart. The electrode on the end of a lead touches the heart wall. The lead delivers electrical impulses to the heart. It also senses the heart’s electrical activity and sends this information back to the pulse generator.
Pacemaker leads may be positioned in the atrium (upper chamber) or ventricle (lower chamber) or both, depending on the medical condition. If the heart’s rate is slower than the programmed limit, an electrical impulse is sent through the lead to the electrode and causes the heart to beat at a faster rate. When the heart beats at a rate faster than the programmed limit, the pacemaker generally monitors the heart rate and will not pace. Modern pacemakers are programmed to work on demand only, so they do not compete with natural heartbeats. Generally, no electrical impulses are sent to the heart unless the heart’s natural rate falls below the pacemaker’s lower limit.
What is an implantable cardioverter defibrillator?
An implantable cardioverter defibrillator (ICD) is an electronic device that is surgically implanted just below the collarbone or on the side of the torso and is used to help control electrical problems with the heart. An ICD senses the rate and regularity of the heartbeat. When the heart rate exceeds a rate programmed into the device, the ICD delivers a small, electrical pulse to the heart to slow the heart rate. When the heartbeat becomes so erratic and disorganized that the heart muscle cannot pump blood from the ventricles, an ICD can deliver a stronger electrical pulse — often referred to as a “shock” — that can restore organized electrical activity, and therefore an effective heartbeat, to the ventricles.
A defibrillator can record and store information about the heart rhythm and therapies delivered by the device for our specialists to review. This allows our cardiologists to have a better understanding of the specific issues going on in the child’s heart. Learn more about the heart’s electrical conduction system.
How is a defibrillator different from a pacemaker?
A pacemaker is typically used to regulate a heart rhythm that is too slow and a defibrillator is generally used to regulate a heart that beats too fast. Some defibrillators can, however, be programmed to function as a basic pacemaker as needed. Sometimes after a defibrillator delivers a shock to the heart, it may beat too slowly. Some defibrillators have a “back-up” pacemaker that can stimulate the heart to beat faster until the normal heart rhythm returns. Additionally, some defibrillators can act as a pacemaker not only after a shock is delivered, but also any time the heart rate drops below a preprogrammed rate.
Which types of heart problems require a defibrillator?
A defibrillator may be inserted in survivors of sudden cardiac arrest, syncope (fainting) due to ventricular arrhythmia or some inherited heart conditions. Some other reasons for a defibrillator include, but are not limited to, the following:
- Ventricular fibrillation. A life-threatening condition in which the ventricles contract in a rapid, chaotic rhythm and cannot pump blood to the body.
- Ventricular tachycardia. A serious condition in which the ventricles cause a fast heartbeat.
- Heart failure. The heart is unable to pump blood effectively to meet the body’s needs. Learn more about heart failure.
- Channelopathies. Genetic disorders caused by disturbances in function of the ion channels that can cause abnormal heartbeats and ECG changes that put children at a higher risk for sudden cardiac death.
Which types of heart arrhythmias require a pacemaker?
A pacemaker may be inserted in order to provide stimulation when the heart is beating too slowly and when other treatment methods, such as medication, have not improved the heart rate. Some examples of heart rate and rhythm problems for which a pacemaker might be inserted include:
- Bradycardia. Occurs when the heart beats too slowly.
- Tachy-brady syndrome. An arrhythmia in which the heart alternates by beating too fast and too slow.
- Heart block. Occurs when the electrical signal is delayed or blocked after leaving the sinus node; there are several types of heart blocks.
There may be other reasons for a child’s doctor to recommend a pacemaker insertion.
What are the risks of defibrillator or pacemaker insertion?
Possible risks of defibrillator insertion include, but are not limited to, the following:
- Bleeding from the incision or catheter insertion site.
- Damage to the vessel at the catheter insertion site.
- Infection of the incision or catheter site.
- The condition pneumothorax. If the lung is accidentally punctured during the procedure, air gets trapped in the space between lung and chest wall. This can interfere with breathing and in extreme cases may cause the lung to collapse.
Caregivers should notify the patient’s cardiologist if the child has an allergy or sensitivity to medications or latex.
How can a family/patient prepare for the defibrillator or pacemaker insertion procedure?
Understandably, patients and their families may be nervous or anxious about having a defibrillator inserted. Prior to the procedure, one of our specialists will explain the procedure in detail and provide the patient and caregivers the opportunity to ask questions. There are never dumb questions, even those that may seem obvious. It is important for the cardiologist to know as much as possible about the patient before the procedure. Caregivers should bring the following information to the last appointment before the defibrillator insertion:
- Details on any sensitivities or allergies the child may have to medications, iodine, latex, tape or anesthesia.
- A list of all medications (prescription and over-the-counter) and herbal or other supplements.
- Details on any other medical conditions the child is currently experiencing or has had in the past.
At this appointment, the child’s legal guardian will be asked to sign a consent form that gives the cardiologist permission to do the defibrillator insertion. It is important to read the form carefully and ask questions if something is not clear. The child’s doctor will also provide details on fasting (not eating) before surgery, any blood tests needed prior to the procedure and information on how long the patient may stay at the hospital.
What should a patient expect the day of the procedure?
A defibrillator or pacemaker may be inserted on an outpatient basis or as part of an overnight stay in a hospital. The length of the child’s hospital stay will be discussed at the final appointment before the procedure.
- All patients are admitted to the Tidwell Procedure Center at CHOC and are asked to arrive two hours prior to the scheduled procedure. Learn more about checking in and what to expect at the procedure center.
- Patients are prepared for the procedure in the preoperative unit (also called “pre-op”) before being taken to the surgical room. While in pre-op, patients may receive an IV, change into a hospital gown and be given a slight sedative to help them feel less anxious.
- Once taken to one of our state-of-the-art operating rooms, the child is connected to an electrocardiogram (ECG or EKG) monitor that records the electrical activity of the heart and monitors the heart during the procedure using small, adhesive electrodes. The child’s vital signs (heart rate, blood pressure, breathing rate and oxygenation level) are monitored throughout the procedure and an anesthesiologist will be present the entire time to keep the child comfortable.
- The device insertion site is cleansed with antiseptic soap and sterile towels and a sheet will be placed around the area. A local anesthetic will be injected into the skin at the insertion site.
- Once the anesthetic has taken effect, the cardiologist will make a small cut at the insertion site.For traditional ICDs, a sheath, or introducer, is inserted into a blood vessel, usually under the collarbone. The sheath is a plastic tube through which the lead wire is inserted into the blood vessel and directed toward the heart. Once the lead wire is inside the heart, it is tested to make sure it is in the right spot and that it works. Depending upon the child’s condition, more than one lead wire may be inserted. Fluoroscopy, a special type of X-ray displayed on a TV monitor, may be used to assist in testing the location of the leads. The defibrillator or pacemaker is slipped under the skin through the incision (just below the collarbone). Generally, it is placed on the nondominant side. Children who are right-handed will have their device placed in their upper left chest. Children who are left-handed will have their device placed in their upper right chest. For subcutaneous ICDs, a small pocket is formed under the skin on the side of the torso, and the pulse generator is placed. Two small incisions are then made near the breastbone to allow the electrode to be placed under the skin and attached to the pulse generator. Fluoroscopy is not needed for the insertion of a subcutaneous ICD.
- The electrocardiogram is monitored to ensure that the defibrillator is working correctly.
- Once the doctor is certain that the device is working properly, the skin incision is closed with sutures, adhesive strips or special glue.
- A sterile bandage or dressing will be applied.
What can patients and families expect after the insertion procedure?
After the procedure, most patients recover in the procedure center’s PACU before returning to the pre-op unit to be discharged home. Some, more critically ill patients, may recover and stay inpatient after the procedure in our CVICU After proper postoperative recovery, most patients:
- Can get out of bed with assistance. The nurse will assist the patient and will check the child’s blood pressure while lying in bed, sitting and standing.
- Are able to eat or drink once completely awake.
- Experience soreness or pain at the insertion site. The child will be provided pain medication as needed.
What happens when a child comes home from the hospital with a defibrillator or pacemaker?
Most patients should be able to return to their daily routine the next day after the insertion of a defibrillator or pacemaker. The patient’s doctor will provide details on when the child can return to his or her daily activities. The doctor may limit the lifting, pulling or certain types of play or movements depending upon the child’s condition and the placement of the pacemaker. Most patients are able to resume their usual diet, unless the doctor instructs otherwise. It will be important to keep the insertion site clean and dry. Patients and caregivers are given specific instructions about bathing and showering, as the insertion site needs to be kept clean and dry while it heals. Caregivers should notify the child’s doctor of the following:
- Fever and/or chills
- Increased pain, redness, swelling or bleeding or other drainage from the insertion site
- Chest pain/pressure, nausea and/or vomiting, profuse sweating, dizziness and/or fainting
- Palpitations (fast or irregular heartbeat).
The child’s doctor may give additional instructions after the procedure, depending on the child’s particular situation and all patients are closely monitored by our Pacemaker and ICD Program.