Overview
An implantable cardioverter defibrillator is a small electronic device placed under the skin of your chest to monitor your heart rhythm continuously and treat dangerous abnormalities. About the size of a small cell phone, the ICD contains a battery, sophisticated computer circuits, and connects to your heart through one or more insulated wires called leads.
The device monitors every heartbeat, analyzing the rhythm thousands of times per day. When it detects a normal rhythm, it does nothing. But when it identifies a dangerously fast or chaotic rhythm, it responds immediately with the appropriate therapy.
ICDs can deliver several types of treatment. For moderately fast rhythms, the device may deliver painless pacing pulses to restore normal rhythm. This is called anti-tachycardia pacing and you typically won’t feel it working. For more dangerous rhythms, the ICD delivers cardioversion, a moderate-energy shock that feels like a strong thump in your chest. In the most severe situations, when your heart goes into ventricular fibrillation or very fast ventricular tachycardia, the ICD delivers defibrillation, a high-energy shock strong enough to reset your heart’s rhythm. This feels like a kick in the chest but lasts only a second.
Modern ICDs also function as pacemakers, treating slow heart rhythms if needed. Some advanced models, called CRT-Ds (cardiac resynchronization therapy defibrillators), have additional leads that help coordinate the pumping action of a weakened heart while still providing protection against dangerous rhythms.
The battery in an ICD typically lasts five to seven years, though this varies based on how often the device needs to deliver therapy. When the battery runs low, the entire device is replaced in a procedure similar to the original implantation, though the leads usually remain in place.
Having an ICD means you carry life-saving technology with you at all times. The device provides peace of mind, knowing that if a dangerous rhythm occurs, treatment happens within seconds, whether you’re awake or asleep, at home or away.
Why You Might Need One
ICDs are recommended for people at high risk of sudden cardiac death from ventricular arrhythmias. These dangerous rhythms originate in the heart’s lower chambers and can be fatal without immediate treatment.
You might need an ICD if you’ve survived sudden cardiac arrest. Having one episode significantly increases your risk of another, and an ICD provides protection. Similarly, if you’ve experienced sustained ventricular tachycardia, where your heart’s lower chambers beat dangerously fast for more than 30 seconds, an ICD can prevent this from becoming life-threatening.
People with severe heart failure, particularly those with an ejection fraction below 35 percent, often receive ICDs. A weakened heart is more prone to developing dangerous rhythms. The ejection fraction measures how much blood your heart pumps with each beat; below 35 percent means your heart is significantly weakened.
Certain inherited heart conditions increase sudden cardiac death risk. Hypertrophic cardiomyopathy, where the heart muscle becomes abnormally thick, can trigger dangerous rhythms, especially during exercise. Long QT syndrome, Brugada syndrome, and arrhythmogenic right ventricular cardiomyopathy are genetic conditions that affect the heart’s electrical system and may require ICD protection.
If you’ve had a heart attack, the damaged scar tissue can create abnormal electrical circuits that trigger ventricular arrhythmias. Your doctor assesses your risk based on how much damage occurred, how well your heart pumps, and whether testing reveals you’re prone to these rhythms.
Some people receive ICDs as primary prevention, meaning they haven’t had a dangerous rhythm yet but are at high risk. Others get them for secondary prevention after surviving a cardiac arrest or dangerous arrhythmia. Your doctor determines your need based on your heart function, symptoms, family history, and results from tests like echocardiograms and electrophysiology studies.
Not everyone with heart disease needs an ICD. Your doctor considers many factors, including your overall health, life expectancy, and personal preferences when making this recommendation.
Before the Procedure
Preparation for ICD implantation involves thorough testing to confirm you need the device and to plan the procedure. You’ll have an electrocardiogram, echocardiogram, and blood tests. Some patients undergo cardiac catheterization or electrophysiology studies to better understand their heart condition and arrhythmia risk.
Your doctor reviews all medications you take. Blood thinners require special attention. Depending on which medication you use and your bleeding risk, you may need to stop or adjust the dose before surgery. Some patients switch temporarily to short-acting blood thinners that are easier to manage around surgery. Never stop medications without your doctor’s guidance.
If you take medications for diabetes, you’ll receive specific instructions about adjusting doses since you’ll be fasting before the procedure. Your blood sugar will be monitored closely during and after implantation.
The night before surgery, stop eating and drinking after midnight. You may be allowed to take certain medications with a small sip of water in the morning. Follow your doctor’s instructions exactly.
Plan for someone to drive you to the hospital and take you home. You’ll stay in the hospital at least one night, possibly two, so pack accordingly. Bring comfortable, loose-fitting clothing that buttons in the front, making it easier to dress without raising your arms above your shoulders.
Shower with antibacterial soap the night before and morning of the procedure if your doctor recommends it. This helps reduce infection risk. Don’t apply lotions, powders, or deodorant on the morning of surgery.
Discuss your concerns and questions with your doctor. Understanding what to expect can reduce anxiety. Some medical centers offer the opportunity to speak with other ICD patients, which many people find reassuring.
If you have an existing pacemaker or ICD being replaced, bring your device ID card to the hospital. The information helps the medical team plan your procedure.
The Procedure
ICD implantation typically takes two to four hours and is performed in an electrophysiology lab or operating room. The procedure is similar to pacemaker implantation but may take longer because of additional testing required.
You’ll receive sedation through an IV to help you relax, along with local anesthetic at the implant site. Most patients remain awake but drowsy, though general anesthesia is used in some cases. Your heart rhythm, blood pressure, and oxygen levels are monitored continuously throughout the procedure.
Your doctor makes an incision below your left collarbone, usually about three to four inches long. The incision goes through the skin and underlying tissue, creating a pocket for the ICD. Because ICDs are larger than pacemakers, the pocket must accommodate the bigger device.
Using X-ray guidance, your doctor threads one to three insulated wires (leads) through a vein near your collarbone into your heart. One lead typically goes to the right ventricle. If you’re receiving a dual-chamber ICD, a second lead is placed in the right atrium. For a CRT-D device, a third lead is threaded through the coronary sinus to pace the left side of your heart.
Once the leads are positioned, they’re tested extensively. Your doctor checks that they can sense your heart’s electrical signals, deliver pacing pulses effectively, and successfully deliver shocks if needed. This testing phase is crucial and may take significant time.
In some cases, your doctor may intentionally induce a dangerous rhythm to verify the ICD can detect and treat it properly. You’ll be briefly unconscious for this test, and the ICD will shock your heart back to normal rhythm. While this sounds frightening, it ensures the device will work when you need it.
After testing confirms everything functions properly, the leads are connected to the ICD generator. Your doctor programs the device with settings tailored to your specific needs, determining what heart rates trigger therapy and how much energy to deliver. The device is placed in the pocket, and the incision is closed with stitches or surgical glue.
A sterile dressing covers the site. You’ll have some restrictions on arm movement initially to allow the leads to settle securely into your heart tissue.
What to Expect During the Procedure
The sedation keeps you relaxed and drowsy throughout most of the procedure. You’ll feel the sting of the local anesthetic injection, which quickly numbs the area. As your doctor creates the pocket for the device, you might feel pressure or pulling sensations, but these shouldn’t be painful.
Threading the leads through your veins and positioning them in your heart is painless. You won’t feel the wires moving through your blood vessels or touching your heart. When the leads are tested with pacing pulses, you might notice your heart beating faster or feel a fluttering sensation. This is temporary and nothing to worry about.
If your doctor needs to test the defibrillation function by inducing a dangerous rhythm, you’ll be given additional medication to make you unconscious for those few seconds. You won’t remember this part of the procedure. When the ICD shocks your heart back to normal rhythm during testing, you’re already unconscious and won’t feel it.
The most uncomfortable part for many people is lying still on the operating table for an extended period. Your back might become stiff or sore. Let the medical team know if you need slight position adjustments, though you must stay relatively still during critical moments.
Throughout the procedure, the team communicates with you, explaining what they’re doing and checking on your comfort level. Don’t hesitate to speak up if you feel pain, anxiety, or need anything.
After the Procedure
After ICD implantation, you’ll move to a recovery area where nurses monitor your heart rhythm, blood pressure, incision site, and overall condition. The first few hours focus on ensuring no complications develop and that you recover well from sedation.
You’ll need to keep your upper body elevated and avoid lying completely flat initially. The incision site will be covered with a sterile dressing. Some pain, swelling, and bruising around the implant site are normal. Pain medication helps manage discomfort.
Before leaving the hospital, an ICD technician checks your device using a programmer. This external device communicates with your ICD through your skin, reviewing all settings and confirming proper function. You’ll receive detailed information about your specific ICD model, including an ID card to carry at all times.
The technician explains what sensations you might feel if the device delivers therapy. Pacing feels like nothing or perhaps a flutter. Cardioversion feels like a strong thump or kick in the chest. Defibrillation feels like a more intense kick but lasts only a second. While these shocks can be startling, they’re saving your life.
You’ll learn about your ICD’s remote monitoring system if your device has this capability. A bedside monitor sends information about your heart rhythm and device function to your doctor’s office automatically. This allows close monitoring without frequent office visits.
Most patients stay in the hospital one to two nights. You’ll need someone to drive you home, as you cannot drive immediately after the procedure. Driving restrictions vary by location and your specific situation, but typically you cannot drive for at least a week, and longer if the ICD was placed after a cardiac arrest or dangerous arrhythmia.
Recovery and Care at Home
Recovery from ICD implantation takes several weeks. The incision site needs time to heal, and the leads must settle securely into your heart tissue. Following your doctor’s instructions carefully during this period is crucial for good outcomes.
Keep the incision clean and dry. You can shower after a few days, but avoid soaking in bathtubs, hot tubs, or swimming pools for at least two weeks. When showering, let water run over the area gently but don’t scrub. Pat the incision dry carefully.
Don’t raise your arm on the ICD side above shoulder height for four to six weeks. This restriction prevents the leads from becoming dislodged before they’re firmly anchored. You can use your arm normally for eating, writing, and other daily activities, but avoid reaching overhead, lifting heavy objects, or vigorous arm movements.
Pain and discomfort gradually improve over the first week or two. Over-the-counter pain relievers like acetaminophen usually provide adequate relief. The implant site may feel tender, and you might notice the device as a slight bulge under your skin. This is normal and becomes less noticeable over time.
Your incision will be closed with stitches that are typically removed seven to ten days after surgery, or with dissolvable stitches that disappear on their own. Once healed, you’ll have a scar that fades gradually.
Start with light activities and gradually increase as you feel able. Walking is encouraged and helps prevent blood clots. Avoid strenuous exercise, heavy lifting (more than ten pounds), and vigorous activities for at least four to six weeks.
Your first follow-up appointment occurs within two weeks. Your doctor checks the incision, reviews your symptoms, and may interrogate your ICD to see if it has recorded any arrhythmias or delivered any therapy. After that, regular checkups occur every three to six months.
Living with an ICD
Living with an ICD requires some adjustments, but most people return to normal, active lives. The device works silently in the background, and many people forget about it most of the time.
If your ICD delivers a shock, it can be startling and uncomfortable, but remember it just saved your life. Sit or lie down immediately after a shock. If you feel fine after a few minutes and don’t receive additional shocks, call your doctor to report the event. If you receive multiple shocks within a short period or feel unwell after a shock, call emergency services.
Keep your ICD ID card with you always. This card contains vital information about your device that emergency personnel and other healthcare providers need to know. Wear a medical alert bracelet or necklace indicating you have an ICD.
Cell phones are safe but should be kept at least six inches from your ICD. Don’t carry your phone in a chest pocket over the device. When talking, hold the phone to your ear on the opposite side.
Most household appliances and electronics are safe. Microwaves, computers, TVs, and other common devices won’t affect your ICD. However, avoid strong magnetic fields. Keep magnets away from your ICD, as they can temporarily disable it.
Many newer ICDs are MRI-conditional, meaning they’re safe for MRI scans under specific conditions. Always inform healthcare providers about your ICD before any medical procedure. Some procedures like lithotripsy (kidney stone treatment) or electrocautery during surgery require special precautions.
Airport security systems may detect your ICD. Show your ID card to security personnel. You can walk through metal detectors, but don’t linger in them. Hand-held security wands shouldn’t be held over your device for more than a few seconds.
Exercise is encouraged once you’ve healed. Discuss your specific exercise plans with your doctor. Most activities are safe, but contact sports that could damage the device should be avoided. Swimming, golf, tennis, and other recreational activities are generally fine.
Driving restrictions vary by location and circumstance. If your ICD was placed to prevent future problems and you’ve never had a dangerous arrhythmia, you might be cleared to drive within a week. If the ICD was placed after cardiac arrest or if you receive shocks, driving restrictions may be several months. Follow your doctor’s and your local regulations carefully.
Some people experience anxiety about receiving shocks or worry constantly about their heart rhythm. This is understandable but can significantly impact quality of life. Support groups, counseling, and sometimes medication can help manage these feelings.
What Happens Without an ICD
Without an ICD, people at high risk for sudden cardiac arrest face serious, often fatal consequences. Ventricular fibrillation and rapid ventricular tachycardia cause sudden cardiac death within minutes if not treated immediately.
If you’ve survived sudden cardiac arrest once, your risk of it happening again is very high without an ICD. Each episode can cause permanent heart damage or death. Most sudden cardiac arrests occurring outside hospitals are fatal because emergency treatment doesn’t arrive quickly enough.
For people with severely weakened hearts, dangerous rhythms can develop without warning. These episodes may occur during sleep, exercise, or completely at rest. Without an ICD’s instant response, there’s no time to reach a hospital for treatment.
People with inherited heart rhythm disorders face ongoing risk throughout their lives. These genetic conditions can trigger fatal arrhythmias at any age, often during physical activity or emotional stress. An ICD provides continuous protection that medications alone cannot match.
The psychological toll of living at high risk without protection is significant. Constant worry about when a dangerous rhythm might occur, fear of exercising or being alone, and anxiety about sudden death severely diminish quality of life. An ICD alleviates these fears by providing reliable, automatic protection.
When to Call Your Doctor
Contact your doctor immediately if you notice signs of infection at the incision site: increasing redness, swelling, warmth, drainage, or fever above 100.4°F (38°C). Infections require prompt treatment with antibiotics and sometimes device removal.
Call your doctor if you receive a shock from your ICD. Even if you feel fine afterward, your doctor needs to know. The ICD stores detailed information about what happened, and this data helps your doctor determine if the shock was appropriate and if any adjustments are needed. If you receive multiple shocks in a short period or feel unwell after a shock, call emergency services immediately.
Seek emergency care for severe chest pain, especially if accompanied by shortness of breath, sweating, or pain radiating to your arm or jaw. These symptoms could indicate a heart attack.
Report symptoms that might indicate your ICD isn’t working properly: return of fainting spells, dizziness, unusual fatigue, or palpitations that don’t resolve. The device may need programming adjustments.
If you notice swelling, increasing pain, or changes in how the ICD site looks or feels, contact your doctor. The device should sit flat under your skin. If it seems to be protruding more or if the skin over it looks thin or irritated, evaluation is needed.
Persistent hiccups or muscle twitching in your chest or abdomen might indicate a lead has moved and is stimulating nearby nerves or muscles. This requires evaluation and possible repositioning.
Before any medical or dental procedure, inform the healthcare provider about your ICD. Some procedures require special precautions, and your ICD may need to be temporarily programmed to a different mode.
Never miss scheduled ICD checkups. These appointments are crucial for monitoring battery life, reviewing any arrhythmias you’ve had, checking that the device delivered appropriate therapy, and making necessary adjustments. Regular monitoring ensures your ICD continues providing optimal protection.
If you experience significant anxiety, depression, or fear related to your ICD, talk to your doctor. These feelings are common and treatable. Mental health support is an important part of living well with an ICD.
You may also like to read these:
Cardiac Resynchronization Therapy (CRT): Procedure, and Benefits
Arrhythmias: Symptoms, Causes, and Treatment
Reference: ICD
