Cardiovascular Tests and Procedures
Implantable Cardioverter Defibrillator (ICD) Insertion
What is an implantable cardioverter defibrillator (ICD) insertion?
An implantable cardioverter defibrillator (ICD) insertion is the implantation of an electronic device (just below the collarbone) used to help regulate electrical problems with the heart. An ICD monitors the heart's electrical activity and responds with either anti-tachycardia pacing (ATP) or shock therapy to prevent sudden cardiac arrest. An ICD can also record and store information about your heart rhythm and therapies delivered by the ICD for your physician to review.
The heart's electrical conduction system:
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The heart is basically a pump made up of muscle tissue that is stimulated by electrical currents, which normally follow a specific circuit within the heart.
This normal electrical circuit begins in the sinus or SA node, which is a small mass of specialized tissue located in the right atrium (upper chamber) of the heart. The SA node generates an electrical stimulus at 60 to 100 times per minute under normal conditions; this electrical impulse from the SA node starts the heartbeat.
The electrical impulse travels from the SA node to the atrioventricular (AV) node in the bottom of the right atrium. From there the impulse continues down an electrical conduction pathway called the "His-Purkinje" system into the ventricles (lower chambers) of the heart. When the electrical stimulus occurs it causes the muscle to contract and pump blood to the rest of the body. This process of electrical stimulation followed by muscle contraction is what makes the heart beat.
An ICD may be needed when the electrical stimulation becomes chaotic and randomly starts in the ventricles instead of in the SA node in the right atrium. A variety of common cardiac conditions such as heart attacks and heart failure can lead to this type of electrical malfunction in the heart.
What is an implantable cardioverter defibrillator (ICD)?
An implantable cardioverter defibrillator (ICD) is a small, electronic device that continuously monitors the electrical activity of the heart. It is about the size of a stop watch and is usually inserted under the skin in the upper chest. It consists of a pulse generator and wires, called leads. The pulse generator contains the battery and a tiny computer. One or more lead wires connect the pulse generator to specific locations in the heart. Although an ICD is a small device, it has many life-saving functions. Four key functions are anti-tachycardia pacing (ATP), cardioversion (light shock), defibrillation (stronger shock), and backup pacing.
ATP involves rapid regular pacing impulses delivered in order to correct and restore normal rhythm by overtaking a fast irregular rhythm. Most people are unaware when this therapy is being delivered.
Cardioversion (light shock) impulses are the next level of therapy. This light shock can generally be felt but not strongly. Defibrillation, which is described by many as feeling like a "kick in the chest," is the strongest therapy that an ICD can be programmed to deliver.
The ICD can also be programmed to function as a basic pacemaker as needed. Sometimes after a shock is delivered, the heart may beat too slowly. The ICD has a "back-up" pacemaker, which can stimulate the heart to beat faster until the normal heart rhythm returns. Additionally, an ICD can act as a pacemaker not only after a shock is delivered, but also any time the heart rate drops below a pre-programmed rate.
These therapies (ATP, cardioversion, defibrillation, and basic pacing) are programmed by your physician. Generally, the mildest form of treatment (ATP) is delivered first, and then additional treatments (cardioversion or defibrillation) are added if the others do not restore the normal heart rhythm. Your physician will program your ICD to your specific needs.
Why are biventricular pacemakers and internal cardioverter defibrillators sometimes combined?
Persons with severe heart failure may benefit from cardiac resynchronization therapy, or CRT. A biventricular pacemaker is the device that is implanted to provide this therapy, which synchronizes the pumping of the right and left lower chambers (ventricles) of the heart. Individuals receiving CRT may also be at risk for sudden cardiac arrest, so the biventricular pacemaker may be programmed to provide any of the four therapies (ATP, cardioversion, defibrillation, and basic pacing) that your physician feels is needed to reduce the risk of sudden cardiac arrest.
Other related procedures that may be used to assess the heart include resting and exercise electrocardiogram (ECG), Holter monitor, signal-averaged ECG, cardiac catheterization, chest x-ray, computed tomography (CT scan) of the chest, echocardiography, electrophysiology studies, magnetic resonance imaging (MRI) of the heart, myocardial perfusion scans, radionuclide angiography, and ultrafast CT scan. Please see these procedures for additional information.
An ICD may be inserted in survivors of sudden cardiac arrest, syncope (fainting) due to ventricular arrhythmia, or some inherited heart conditions.
Some other reasons for implanting an ICD 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 metabolic needs.
- others at risk for sudden cardiac arrest due to family history or other known conditions
There may be other reasons for your physician to recommend an ICD insertion.
Possible risks of ICD 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
- pneumothorax - air becomes trapped in the pleural space causing the lung to collapse
If you are pregnant or suspect that you may be pregnant, you should notify your physician. If you are breastfeeding, you should notify your physician.
Patients who are allergic to or sensitive to medications or latex should notify their physician.
For some patients, having to lie still on the procedure table for the length of the procedure may cause some discomfort or pain.
There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
- Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
- You will be asked to sign a consent form that gives your permission to do the test. Read the form carefully and ask questions if something is not clear.
- Notify your physician if you are sensitive to or are allergic to any medications, iodine, latex, tape, or anesthetic agents (local and general).
- You will need to fast for a certain period of time prior to the procedure. Your physician will notify you how long to fast, usually overnight.
- If you are pregnant or suspect that you are pregnant, you should notify your physician.
- Notify your physician of all medications (prescription and over-the-counter) and herbal or other supplements that you are taking.
- Notify your physician if you have heart valve disease, as you may need to receive an antibiotic prior to the procedure.
- Notify your physician if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop some of these medications prior to the procedure.
- Your physician may request a blood test prior to the procedure to determine how long it takes your blood to clot. Other blood tests may be done as well.
- You may receive a sedative prior to the procedure to help you relax. If a sedative is given, you will need someone to drive you home afterwards.
- The upper chest may be shaved or clipped prior to the procedure.
- Based upon your medical condition, your physician may request other specific preparation.
An implanted cardioverter defibrillator insertion may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your physician's practices.
Generally, an ICD insertion follows this process:
- You will be asked to remove any jewelry or other objects that may interfere with the procedure.
- You will be asked to remove your clothing and will be given a gown to wear.
- You will be asked to empty your bladder prior to the procedure.
- An intravenous (IV) line will be started in your hand or arm prior to the procedure for injection of medication and to administer IV fluids, if needed.
- You will be placed on your back on the procedure table.
- You will be 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. Your vital signs (heart rate, blood pressure, breathing rate, and oxygenation level) will be monitored during the procedure.
- Large electrode pads will be placed on the front and back of the chest.
- You will receive a sedative medication in your IV before the procedure to help you relax. However, you will likely remain awake during the procedure.
- The ICD insertion site will be cleansed with antiseptic soap.
- Sterile towels and a sheet will be placed around this area.
- A local anesthetic will be injected into the skin at the insertion site.
- Once the anesthetic has taken effect, the physician will make a small incision at the insertion site.
- A sheath, or introducer, is inserted into a blood vessel, usually under the collarbone. The sheath is a plastic tube through which the ICD lead wire will be inserted into the blood vessel and advanced into the heart.
- It will be very important for you to remain still during the procedure so that the catheter does not move out of place and to prevent damage to the insertion site.
- The lead wire will be inserted through the introducer into the blood vessel. The physician will advance the lead wire through the blood vessel into the heart.
- Once the lead wire is inside the heart, it will be tested to verify proper location and that it works. There may be one, two, or three lead wires inserted, depending on the type of device your physician has chosen for your condition. Fluoroscopy, (a special type of x-ray that will be displayed on a TV monitor), may be used to assist in testing the location of the leads.
- The ICD generator will be slipped under the skin through the incision (just below the collarbone) after the lead wire is attached to the generator. Generally, the generator will be placed on the non-dominant side. (If you are right-handed, the device will be placed in your upper left chest. If you are left-handed, the device will be placed in your upper right chest).
- The ECG will be observed to monitor ICD function.
- The skin incision will be closed with sutures, adhesive strips, or special glue.
- A sterile bandage/dressing will be applied.
In the hospital:
After the procedure, you may be taken to the recovery room for observation or returned to your hospital room. A nurse will monitor your vital signs.
You should immediately inform your nurse if you feel any chest pain or tightness, or any other pain at the incision site.
After the period of bed rest has been completed, you may get out of bed. The nurse will assist you the first time you get up, and will check your blood pressure while you are lying in bed, sitting, and standing. You should move slowly when getting up from the bed to avoid any dizziness from the period of bedrest.
You will be able to eat or drink once you are completely awake.
The insertion site may be sore or painful, but pain medication may be administered if needed.
Your physician will visit with you in your room while you are recovering. The physician will give you specific instructions and answer any questions you may have.
Once your blood pressure, pulse, and breathing are stable and you are alert, you will be taken to your hospital room or discharged home.
If the procedure is performed on an outpatient basis, you may be allowed to leave after you have completed the recovery process. However, if there are concerns or problems you may stay in the hospital for an additional day or longer.
You should arrange to have someone drive you home from the hospital following your procedure.
You should be able to return to your daily routine within a few days. Your physician will tell you if you will need to take more time in returning to your normal activities. In addition, you should not do any lifting or pulling on anything for a few weeks. You may be instructed to limit movement of the arm on the side that the ICD was placed, based on your physician's preferences.
You will most likely be able to resume your usual diet, unless your physician instructs you differently.
It will be important to keep the insertion site clean and dry. You will be given instructions about bathing and showering.
Your physician will give you specific instructions about driving. You will not be able to drive until your physician gives you approval. These limitations will be explained to you, if they are applicable to your situation.
You will be given specific instructions about what to do the first time your ICD delivers a shock. For example, you may be instructed to dial 911 or go to the nearest emergency room in the event of a shock from the ICD. Calming yourself with slow deep breaths can be helpful if you are anxious after a shock.
Ask your physician when you will be able to return to work. The nature of your occupation, your overall health status, and your progress will determine how soon you may return to work.
Notify your physician to report any 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
Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.
The following precautions should always be considered. Discuss the following in detail with your physician, or call the company that made your device:
- Always carry an ID card that states you have an ICD. In addition, you may want to wear a medical identification bracelet indicating that you have an ICD.
- Use caution when going through airport security detectors. In particular, you may need to avoid being screened by hand-held detectors as they may interfere with your ICD.
- Anti-theft systems or electronic article surveillance (EAS) used in department stores may interact with an ICD. The American Heart Association recommends you should not lean on or stand in this equipment but should pass quickly through the detection system.
- You may not have a magnetic resonance imaging (MRI) procedure. You should also avoid large magnetic fields such as power generation sites and industrial sites such as automobile junkyards that use large magnets.
- Abstain from diathermy (the use of heat in physical therapy to treat muscles). Do not use a heating pad directly over your ICD.
- Turn off large motors, such as cars or boats, when working on them. (They may create a magnetic field).
- Avoid high-voltage and radar machinery, such as radio or television transmitters, electric arc welders, high-tension wires, radar installations, or smelting furnaces.
- If you are having a surgical procedure performed, electrocautery should be avoided. (The electrocautery device which controls bleeding may interfere with the ICD).
- You may need to take antibiotic medication before any medically invasive procedure to prevent infections.
- When involved in a physical, recreational, or sporting activity, you should protect yourself from trauma to the ICD. A blow to the chest near the ICD can affect its functioning. If you are hit in that area, you may want to see your physician.
- Cell phones should be kept at least 6 inches away from you ICD. Avoid carrying a cell phone in your breast pocket over your ICD.
- Always consult your physician when you feel ill after an activity, or when you have questions about beginning a new activity.
- Always consult your physician if you have any questions concerning the use of equipment near your ICD.