What does it feel like when a pacemaker goes off?

Implantable Cardioverter Defibrillator (ICD)

ICDs are for people who have had an abnormal, fast heart rate that caused them to faint or caused their heart to stop pumping properly. Sometimes medicines can be used to control these fast heart rates. When medicines do not work, doctors can implant an ICD.

Any irregularity in your heart’s natural rhythm is called an arrhythmia. Almost everyone’s heart skips beats, and these mild palpitations are usually harmless. But there are about 4 million Americans who have recurrent arrhythmias, and these people usually need treatment for their condition.

Electrical impulses from the heart muscle cause your heart to beat (contract). This electrical signal begins in the sinoatrial (SA) node, located at the top of the heart’s upper-right chamber (the right atrium). The SA node is sometimes called the heart’s “natural pacemaker.”

The SA node sends electrical impulses at a certain rate, but your heart rate may still be altered by physical demands, stress, or other factors. Sometimes, the SA node does not work properly, causing the heart to beat too fast, too slow, or irregularly. In other cases, the heart’s electrical pathways are blocked, which can also cause an irregular heart rhythm.When an electrical impulse is released from the SA node, it causes the upper chambers of the heart (the atria) to contract. The signal then passes through the atrioventricular (AV) node. The AV node checks the signal and sends it through the muscle fibers of the lower chambers (the ventricles), causing them to contract.

Why do I need an implantable cardioverter defibrillator (ICD)?

ICDs are for people who have had an abnormal, fast heart rate that caused them to faint or caused their heart to stop pumping properly. Sometimes medicines can be used to control these fast heart rates. When medicines do not work, doctors can implant an ICD.

An ICD is used in patients at risk for

  • Ventricular tachycardia, when the lower chambers of the heart independently beat faster than 100 beats per minute.
  • Ventricular fibrillation, when the muscle fibers of the lower chambers of the heart contract in a fast, uncoordinated manner.
  • Sudden cardiac arrest caused by arrhythmias.

An ICD is usually about the size of a pager. It is made up of two parts:

  • A pulse generator, which includes the battery and several electronic circuits.
  • Wires, called leads. Depending on the type of ICD, you may have one or two leads.

ICD implant surgery has become a very common procedure. It is done while you are asleep, but it is not open heart surgery. After the device is implanted, doctors will perform electrophysiology studies (EPS) to make sure that the device is working properly. The procedure usually takes about two hours. You will need to stay in the hospital for at least one night after the device is implanted. Antiarrhythmic medicines may also be prescribed.The ICD is implanted beneath the skin, near the collarbone or somewhere at or above the waistline. The leads are placed inside the heart or on its surface and are attached to the ICD.

Some of the newer, smaller devices have simpler lead systems, which can be inserted with a catheterization procedure.

Once the ICD is implanted, the leads monitor your heart rate. If the ICD detects ventricular tachycardia or fibrillation, it sends out a controlled burst of impulses (called “overdrive” pacing). If that does not work, the ICD “shocks” the heart to restore a normal rhythm. Newer ICD devices can also work like a pacemaker if a slow heart rate (bradycardia) occurs.

When ventricular tachycardia or fibrillation occurs, the ICD records your heart rate, as well as the date and time of the event. It can also record what electrical therapy was needed to restore a normal heart rhythm.

What will I feel when my ICD gives me a “shock”?

Tachycardia is usually corrected with very small electrical impulses. You may feel a flutter, palpitations (like your heart is skipping a beat), or nothing at all. Fibrillation may require that you receive a “shock.” Most patients say that the shock feels like a sudden jolt or thump to the chest. Some people black out during fibrillation, so they may not feel anything when the shock is given. If someone is touching you while you are receiving a shock, they may feel a small muscle jerk, but it will not hurt them.

Your doctor will tell you what to do after you have received a shock. Some patients’ doctors will have them call the doctor’s office after a shock has been given. Most doctors will want to know if you have received two or more shocks within 24 hours.

How often do I need to get my ICD checked?

After you get your ICD, you will have to go to the doctor for regular check-ups. ICDs can also be checked over the telephone. This is called transtelephonic monitoring. Even with telephone monitoring, you will still need to go to your doctor’s office for regular check-ups.

The ICD is checked with a device called a programmer. When the programmer is held over the ICD, your doctor is able to tell if the ICD is working properly, how much power is left in the battery, and if the device has delivered therapy. The programmer can also be used to change the settings of the ICD.

An ICD battery usually lasts between 4 and 8 years, depending on how many shocks it sends. When the battery runs down, a new ICD will be implanted. In most cases, your original ICD leads will not need to be replaced.

Will electronic devices affect my ICD?

If you have an ICD, you should always be aware of your surroundings. It is safe for you to be around wood working tools and normal home appliances, including microwave ovens. Stay away from heavy equipment that has very strong magnetic fields or strong electric fields (antennas, arc welders, and industrial equipment). Your doctor will help you understand what to avoid when you have an ICD.

Can I still drive a car if I have an ICD?

Many doctors will tell you not to drive for 6 months after your implantation surgery or after a shock. Talk to your doctor if you are not sure if it is safe for you to drive.

Can I use my cell phone if I have an ICD?

You should keep your cell phone at least 6 inches away from your ICD. When you are talking on your cell phone, hold it on the opposite side of the body from your ICD. Do not carry your cell phone in your breast pocket or on your belt if that means that it will be within 6 inches of your ICD.

Tags: arrhythmia, ICD, implantable cardioverter defibrillator, pacemaker, SA node, sinoatrial node (SA node)

Contrary to common belief, pacemakers aren’t just for older folks, or men. Meet three women who share what’s it like to live with this heart-saving device. (Want to pick up some healthier habits? Sign up to get healthy living tips, weight loss inspiration, slimming recipes and more delivered straight to your inbox!)

“I didn’t know when I closed my eyes at night if I was going to wake up in the morning.”

Joan Tak
“In 1991, when I was 34 years old, I got my first pacemaker. I had been diagnosed with SVT—supraventricular tachycardia, which causes little spurts of extremely rapid heart rate. I needed several surgeries: First I had a temporary pacemaker implanted, then a permanent one. Then the pacemaker generator failed, the leads needed to be changed, and the battery failed. Every complication that could possibly happen happened to me.

I was at the peak of my career at the time and I had young children, and my health issues really took a toll on both my career and personal life. If I needed to breastfeed my daughter, I had to have somebody pick my daughter up and hand her to me, because I couldn’t lift more than 5 pounds. It also had an impact on my relationship with my then husband. (We later divorced.) I had a painful scar, and he was afraid to touch me.

Meanwhile, I was let go from my job as a nurse. I was one of the pioneers in subacute care, and it was very demanding. My boss eventually decided that my frequent hospitalizations meant I couldn’t keep up with the pace.

After my son was born, I needed another surgery. Reports had surfaced that some pacemakers had wires that were puncturing patients’ hearts, and I had one of those models. I didn’t know when I closed my eyes at night if I was going to wake up in the morning. I didn’t know if when I hugged my kids if this wire was going to perforate my heart. Just waiting for the surgery was terrifying. I probably should have gone for counseling, but I didn’t. The support groups for pacemakers were for geriatric people, so I didn’t feel like they were for me. (Here’s how to recover from surgery faster, according to experts.)

MORE: Can You Get An MRI With A Pacemaker?

I didn’t expect to survive the surgery to remove the defective pacemaker, but I did. Every day I’d look in mirror, touch the scar on my chest and cringe. It took more than a decade for me to accept the scar. I realized that everything I’d been through paled in comparison to what so many others with different medical conditions have faced, and I’m thankful that my situation was not worse.

Today my condition is stable, and I’ve become more active than I ever imagined. Sometimes I even forget that I have a pacemaker until I have an appointment to get it checked.”
—Joan Tak, 60, Watchung, NJ

“I remember seeing my friends playing outside and being so angry that I couldn’t join them.”

Amanda DeJesus
“I was born with a hole in my heart, so I’ve always had heart disease. When I was 13 years old I was playing sports, so I went to get a regular checkup and was diagnosed with dilated cardiomyopathy, which means that my heart wasn’t pumping properly. I was totally blindsided—I thought I was healthy enough, but a month later I was scheduled for surgery to get a pacemaker to keep my heartbeat at a normal, regular rate.

I couldn’t go to school for 3 weeks while I recovered, and afterward I wasn’t myself. I was fatigued all the time and would get short of breath. I had to use the elevator at school instead of the stairs because I had to very closely monitor my heart rate: If it went too high, I’d receive a shock. I remember seeing my friends playing outside and being so angry that I couldn’t join them. I had to quit basketball, and was told I’d never play sports again. That actually wasn’t true—I competed in the 2014 Transplant Games of America, winning a silver medal in discus and a bronze in the shot put competition—but it was enough for a 13-year-old to have a meltdown.

When I was 15, I ended up getting a heart transplant, so I didn’t need the pacemaker anymore; I went without one for 12 years. But just 6 months ago I was diagnosed with an irregular heartbeat, so I had to get another pacemaker put in. It seemed like a small price to pay for getting back to the active lifestyle that I love.

MORE: 26 Health Breathroughs That Will Change Your Life Now

When I first got a pacemaker years ago, I could feel it working on a daily basis: I could feel the zaps it would send to raise my heart rate. Today, medicine and technology have evolved, and the size of my new implant is smaller and less visible. Now I know it’s there, but I don’t necessarily feel it. I seem to notice it more when I lift something a little too heavy or I lie on my left side the wrong way—then it becomes a little uncomfortable. But it’s a lot easier to adjust as an adult than it was as a teenager.”
—Amanda DeJesus, 28, Fresno, TX

“I never wanted anyone to see my scar, so I avoided wearing bathing suits and covered up in formal dresses.”

Tricia Livingston

“From the time I was about 8 years old I’ve complained of feeling dizzy. My mom asked my pediatrician about it multiple times, and he said it was orthostatic hypotension—a condition in which your blood pressure falls dramatically when you stand up quickly—and completely normal. Then one day when I was 13 I had my first extreme episode of what we later found out was supraventricular tachycardia. My mom, who happens to be a nurse in coronary intensive care, took my pulse and it was faster than 220.

I eventually saw a pediatric cardiologist, who had me wear a Holter monitor to record my heart activity for 24 hours. I felt fine that day, but as soon as the doctor looked at the results he called my mom and said I needed to be admitted to the hospital immediately and get a pacemaker. My heart had completely stopped three times in that 24-hour period.

My mom wanted a second opinion, and she began looking for the best doctor she could find. We ended up at Cleveland Clinic, which is about 2.5 hours from my hometown. After a day of tests, the doctor there confirmed that I needed a pacemaker right away. He wouldn’t even allow me to go with my parents to the hotel across the street, because if my heart stopped for a little longer than it had while I was on the Holter monitor I could die.

After the surgery, it hurt to raise my left arm and I wasn’t allowed to carry anything heavy. About 8 weeks later I was back to my normal activities, including playing tennis.

The pacemaker did not “cure” my condition, but it kept me safe. I also got a medication I could take if I was planning on exercising, especially during hot weather. I remember taking it in college before going out dancing, and fortunately it worked well.

My first pacemaker was bigger than they are now. It was placed in a pocket under the breast tissue so it wasn’t very noticeable, but sometimes you could see an edge depending on how I moved. I never wanted anyone to see my scar, so I avoided wearing bathing suits and covered up in formal dresses. If people did see it they would ask tons of questions. Some asked to touch it and if I could feel it. I really hated that.

MORE: The Simple Way To Boost Your Heart Health By 46%

Metal detectors were also an issue. There was one at my college library (to make sure people didn’t leave with a book that hadn’t been checked out). If I was with a study group, I’d make excuses about why I had to stay longer; I didn’t want them seeing me bypassing the normal exit or explaining to the librarians why I’d set off the alarm. Of course, airports were not a treat. I had a card I could show and had to be patted down. Now I love the body scanners at airports! No pat downs. But I still have to show a card and get patted down at sporting events and concerts when there are metal detectors.

I’ve had five pacemakers in 34 years. Because my heart beats normally 90% of the time, my pacemakers last a long time. And I rarely feel my pacemaker “working,” though when I get a new one sometimes I noticed a tiny, sharp pain, which I assume it is just the healing process.”
—Tricia Livingston, 47, Fort Worth, TX

Celia Shatzman Celia Shatzman is a Brooklyn-based writer who has penned stories on topics ranging from fashion to travel to celebrities, entertainment, beauty, finance, health, and fitness.

Patient Education

Pacemaker Failure

Pacemakers are reliable life-saving devices, but problems do rarely occur. It is important to understand why you have a pacemaker. This can also help you understand why it might “fail” and what the potential consequences could be if it does fail.These are some reasons you may have a pacemaker:

  • To help increase your heart rate if it is too slow

  • Damage to the wires within in the heart resulting in heart block

  • Improve congestive heart failure when there is evidence of both heart muscle and wire damage

  • A fast, irregular heart rate that requires medicine or procedures that result in a heart rate that is too slow

Each of the above problems typically causes you to feel symptoms. Thus, if your pacemaker fails to work properly you may experience these symptoms or symptoms resulting from the pacemaker itself. Signs and symptoms of pacemaker failure or malfunction include:

  • Dizziness, lightheaded

  • Fainting or loss of consciousness

  • Palpitations

  • Hard time breathing

  • Slow or fast heart rate, or a combination of both

  • Constant twitching of muscles in the chest or abdomen

  • Frequent hiccups

A complete failure of a modern pacemaker is rare. Most of the time, problems related to a pacemaker occur when it is working properly, but may just need to be reprogrammed. Other times, there might be a true problem with the battery, a lead, or an electrode. These problems can sometimes be fixed with reprogramming of the pacemaker, other times they may require a procedure to fix the problem. This is often called a lead revision.

Causes for a pacemaker failure include:

  • Battery depletion

  • Loose or broken wire between the pacemaker and the heart

  • Electronic circuit failure resulting from a break in wire insulation or a fracture in the wire

  • Electrolyte abnormality (such as high potassium in the blood)

  • Electromagnetic interference from certain devices such as power generators, arc welders, and powerful magnets (found in medical devices, heavy equipment, and motors)

  • A pacemaker lead gets pulled out of position

  • A change in your condition that needs pacemaker reprogramming

Common household devices, such as microwave ovens, TV remotes, heating pads, and electric blankets, don’t interfere with pacemakers. Cell phones in the U.S. do not interfere with pacemakers, but it is recommended that you keep a cell phone on the opposite side of the body from the pacemaker. Most modern day pacemakers are not affected by MRI, but talk with your healthcare provider to know if you can safely have an MRI with your device and if you should take any special precautions first.

Home care

The following are general care guidelines:

  • Don’t push, pull, or twist the pulse generator unit placed under your skin.

  • Carry a wallet ID card with the name of your device and its maker, and the name of your cardiologist. This will help emergency personnel test your pacemaker in the event of a malfunction.

  • Medical and dental equipment can affect pacemakers. Tell the doctor or dentist that you have one before any procedures are done. Routine X-rays will not affect a pacemaker.

Follow-up care

Follow up with your doctor, or as advised.

Have your battery checked at least every 6 months, or as advised by your healthcare provider, to make sure your battery does not become depleted. The generator will need to be changed once the device has reached the elective replacement period just prior to the end of its’ battery life, which is about every 10yrs years, depending on what type of device you have and how much your heart uses the device. Monitoring of the device function and battery strength can sometimes be done using a device connected to your phone line. Or you may be able to transmit information to your healthcare provider over the internet. This is called remote monitoring. Ask your provider if this is an option for you.

When to seek emergent care

You may need to seek emergent care or call 911 if you have any of the following:

  • Trouble breathing

  • Fainting or loss of consciousness

  • Chest pain

  • Frequent or persistent palpitations (the sense that your heart is fluttering or beating fast or hard or irregularly)

  • Slower than usual heart rate compared to your normal

  • Chest pain with weakness, dizziness, fainting, heavy sweating, nausea, or vomiting

  • Extreme drowsiness, confusion

    It is important to keep in mind that these symptoms may be a result of a problem with your pacemaker, however they can be unrelated to the pacemaker function.

When to seek medical advice

Call your healthcare provider right away if any of the following occur:

  • New symptoms of weakness, dizziness, lightheadedness

  • Pain, redness, swelling, drainage from pacemaker implant site or other signs of infection

  • Fever of 100.4°F (38°C) or higher, or as directed by your healthcare provider

  • If your pacemaker generator feels loose or like it is wiggling in the pocket under the skin

  • If you have muscle twitching in your chest or abdomen muscles

  • Hiccups that won’t stop

How to Respond to an Implantable Cardioverter-Defibrillator Shock

The implantable cardioverter-defibrillator (ICD) has consistently demonstrated a life-saving benefit in patients at risk for sudden cardiac arrest. Quality-of-life outcomes with the ICD may be directly related to coping successfully with ICD shocks. Although most people are able to tolerate a shock to some extent, the experience of shock is discomforting and can prompt feelings of anxiety, depression, or fear. The purpose of this article is to review patient and family preparations and responses to ICD shock to limit its impact on quality of life.

Understanding Shock

The ICD provides continuous monitoring and treatment for cardiac arrhythmias (abnormal heartbeats). The ICD automatically detects an abnormal heartbeat and will deliver small rapid pacing impulses or an electric shock to the heart to restore a normal heart rhythm. During the first year after implantation, the chances of receiving at least one ICD shock can range from one third to one half of all ICD recipients.1,2 The shock sensation has been likened to a swift kick in the chest and rated a “6” on a 0 to 10 pain scale.1,3 Nonetheless, quality-of-life research indicates that the ICD is at least equal to or better than antiarrhythmic medications on most indicators of quality of life.2,4–8 Most research has pointed to ICD shock as the primary culprit if reductions in quality of life occur.2

Psychological Responses to Shock

ICD-specific fears and symptoms of anxiety (for example, excessive worry, increased muscle tension, sweating, and increased heart rate and respiratory rate) are the most common psychological symptoms experienced by ICD recipients, with approximately 13% to 38% of recipients experiencing significant levels of anxiety. Common ICD-specific fears include the shock experience, device malfunction, and/or concerns of death. Depressive symptoms are reported at rates similar to those of other heart patients (24% to 33%).9 Younger age (50 years and younger) and greater frequency of ICD shocks were the two most commonly reported ICD-specific risk factors for psychological distress.

How to Respond to ICD Shock

It is possible that you will experience a shock at some point during your time with the ICD. As an ICD patient, you cannot control shocks, but you can control your reaction. Although shocks are often startling and discomforting, they are also an indication that the ICD is doing its job, keeping you protected from life-threatening arrhythmias or a rapid heart rate. Having a plan for shock helps reduce uncertainty and anxiety, so that you and your loved ones know how to handle the shock and in what circumstances you should contact your doctor or go to the emergency room.

Preparing for Shock

  • Educate yourself. Learn as much as you can about the ICD and how it works. Understanding the purpose of the ICD, how it operates, and how to respond if a shock occurs will help to reduce your anxiety and help you to cope more effectively. Join a local support group of heart patients or ICD patients to learn more about cardiac disease and how your ICD works to keep you safe. Review the additional resources listed below to stay informed.

  • Information control. Three sources of information are important to have available at all times: your ICD identification card, a list of your medications, and your doctor’s name and telephone number. This information will allow healthcare providers to take the best possible care of you in an emergency. Use an index card to write down all of your medications and your doctor’s name, and keep it in your wallet.

  • Action plan. Preparing for an ICD shock might involve rehearsing what you should do if you were to receive a shock. Your doctor may have a specific plan for you. The Table contains a typical plan for an ICD patient that you may want to use for a discussion with your doctor.

    Action Plan

    Event Symptoms Action
    Received ICD shock Feel fine immediately Call heart doctor to discuss the event and arrange appropriate follow-up
    Received ICD shock Experiencing chest pain/pressure, shortness of breath, rapid heart action. Feel dizzy, confused, or not well Seek medical attention immediately
    Received two or more ICD shocks within 24 hours Feel fine or ill Seek medical attention immediately

Postshock Coping

Experiencing shock is generally recognized as discomforting, but an organized response can minimize the short- and long-term negative effects. Managing your reaction involves strategies involving both your mind and your actions. The goal of all of these strategies is to maximize your quality of life.

Strategies for Coping With ICD Shock
Relax and Focus

The automatic response to a shock is arousal (a heightened awareness to your body and health). Hyperarousal can occur if you do not take charge of your reaction and focus on relaxing. Allowing yourself to engage in deep-breathing techniques and tension reduction exercises will reduce the effects of arousal. To practice relaxed breathing, do the following:

  • Put yourself in a comfortable, reclined position, and place one hand on your upper chest and the other on your belly, just below your navel (belly button).

  • Close your eyes and focus on your breathing. Notice how the hand on your belly moves more than the hand on your chest, indicating that you are using calm, restful breathing.

  • Keep your attention on your breathing. It is inevitable that your mind will wander to other topics, but just return your attention to your breathing.

  • Practice this exercise for at least 5 minutes twice a day. This will allow you to gain skill and comfort with focusing on your breathing and relaxing your body.

Positive Thinking

Recent research has highlighted how the attitudes of ICD patients are among the best predictors of quality of life.10,11 Shock can reduce your faith in your safety and your future or could serve as a reminder of your commitment to living. Therefore, actively reminding yourself about the positive aspects of your life, your relationships, your activities, and your future can provide you with hopeful ideas and rewarding plans for the future. You may want to make a list of the people and activities that give you quality of life so that you can remind yourself of how important your positive outlook is to recovery.

  • Debriefing. The desire to avoid a shock is universal. Only regular medical follow-up and medications are related to preventing shock at this time. Therefore, the best plan is to discuss the reasons for a shock with your doctor. Your doctor will take every action possible to avoid a future shock by possibly adjusting your medications or the settings of your ICD.

  • Return to life. Quality of life usually involves engaging in activities that are rewarding, pleasant, peaceful, or exciting. Many ICD patients try to avoid a future shock by avoiding any action that has ever preceded a shock, but this can reduce your quality of life. Preventing a shock is not possible by our actions alone. Because shock can occur during any part of daily life, fearfulness about shock can trick you into trying to prevent it by reducing activities. A step-by-step plan can allow you to eventually return to all of the activities that you did before shock. Start a “Coping To-Do List” that highlights both everyday activities that reduce stress (for example, take a warm bath, watch a sunset) and long-term goals (take a vacation or trip, attend an important event) that can provide you with future activities that are motivating to remain healthy.


Experiencing an ICD shock can be an unwelcome reminder about your heart condition. However, the ICD remains the best treatment option to keep you safe from cardiac arrhythmias. Desirable quality of life can also be achieved despite the experience of shock. Collectively, you, your family and significant others, and your healthcare team can plan for shock, engage in preshock and postshock coping strategies, and resume a desirable quality of life.

Additional Resources

The information contained in this Circulation Cardiology Patient Page is not a substitute for medical advice or treatment, and the American Heart Association recommends consultation with a physician or healthcare provider.


Correspondence to Samuel F. Sears, Jr, PhD, University of Florida, Department of Clinical and Health Psychology, Box 100165, UF Health Science Center, Gainesville, FL 32610. E-mail

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FAQ: Implantable Cardioverter Defibrillators

Many people have questions about implantable cardioverter defibrillators (ICDs) — how they work and why a doctor might decide to offer one as part of treatment for a disturbed heart rhythm. Here are a few common questions and answers.

  • Will an ICD cure my heart rhythm problem?
  • Is an ICD the right treatment for all rhythm disturbances?
  • Do shocks from an ICD hurt?
  • If someone touches me when I get an ICD shock, what will happen to them?
  • After the device is implanted, can I return to life as it was before?
  • Where will the defibrillator be placed?
  • Is the implant procedure an open heart operation?
  • How is the ICD powered?
  • How often will my doctor check my ICD?
  • Can people with defibrillators go near microwave ovens?

Will an ICD cure my heart rhythm problem?

No, it won’t. Cure means to completely and permanently eliminate the condition and that’s not what an ICD does. In some cases, an electrophysiogist can provide a cure for a rhythm disturbance, sometimes by performing an ablation.

An implantable defibrillator is most commonly used as a part of a patient’s treatment. It acts instantly if your heart rhythm changes for the worse. It treats the problem, each time it occurs. Many doctors use an ICD in combination with rhythm control medications called antiarrhythmics. The goal, in such cases, is to use medication to keep the rhythm from getting too fast and to use the ICD as a “failsafe” device to protect you if your heart rate increases dangerously despite the medication.

Do ICDs treat all rhythm disturbances?

No. Implantable cardioverter defibrillators are intended to treat very serious rhythm problems that can arise in the lower portion of the heart, called the ventricles. In the future, ICDs will be available that can be used for patients with other rhythm problems.

Good heart rhythm control often can be achieved with medication alone. If your symptoms worsen or if the problem is persistent or potentially dangerous, your doctor may perform an electrophysiology (EP) study to learn more about the rhythm and the best treatments to deal with it. In some cases, an electrophysiologist may not need a study if the problem and its solutions are clear. If an ICD is one of the solutions, your doctor will know and discuss it with you.

Do shocks from an ICD hurt?

Most patients who have received shocks from their ICDs describe them as startling, jolting and unsettling, but not painful. It’s easy to understand why. The ICD delivers a shock to prevent a dangerously fast heart rhythm. The device recognizes the rhythm, which may cause discomfort — dizziness, lightheadedness, palpitations, an “about-to-faint” feeling — and then suddenly, the ICD shock brings the rhythm back to normal. The jolt is a powerful one to control the heart without delay.

If someone touches me when I get an ICD shock, what will happen to them?

Nothing will happen to them. A shock from an ICD is less powerful than a shock given externally such as shocks given by paramedics or emergency room workers who use “paddles” on the chest, called defibrillation. When we defibrillate someone externally, we use a great deal of energy to be certain there is enough to travel to the heart and do the job. The ICD shocks the heart directly, through wiring connected to the heart. It can achieve the same shock with far less energy than external devices. The energy that escapes to the surface, where someone might touch us, is very difficult to detect and completely harmless.

After the device is implanted, can I return to life as it was before?

In many cases, once treatment begins to control your heart rhythm, life can begin to return to normal. In additin to ICDs, treatments include medication, ablation, a pacemaker or a combination of these. Most patients return to work, school and their usual activities including driving, sexual relationships and exercise, once their doctors see that they’re safe. How long it takes depends on the individual patient and the other medical problems you may have.

Where will the defibrillator be placed?

In the past, when ICDs were much larger, they were implanted in the abdomen. Now that they are smaller, doctors usually implant them in the chest, most often below the clavicle or collarbone, on the right or left side of the chest. You may feel and see the outline of the device under the skin.

Is the implant procedure an open heart operation?

No. Implanting an ICD is much simpler than it was a few years ago and often takes less than an hour.

The doctor who performs this procedure is the best source of information about what type of anesthesia will work best for you. As a rule, patients do very well with sedation to keep them in a light state of sleep, in combination with local anesthetic to numb the area where the device is implanted. The incision is usually a small one — three or four inches wide — and travels horizontally on the chest. After the ICD is in place and the incision is closed, the doctor applies a bandage to protect the site.

Most patients notice some soreness for about a week. Doctors advise patients with new ICDs to avoid getting the site wet for several days after it has been implanted.

How is the ICD powered?

Implantable cardioverter defibrillators are powered by batteries. The variety used has been chosen because of its long service period and the very predictable way in which its power is gradually used. If an ICD delivers a great many shocks, it will wear out sooner than one that seldom provides therapy. Most ICDs last five years and often more. Checking the battery is an important part of any evaluation of the device and doctors are careful to do this as a portion of their routine follow-up.

A normal clinic visit to the electrophysiologist or cardiologist usually includes an inspection of the device. This means that we use a piece of equipment, called a programmer, to “ask” the ICD to show its battery voltage, its settings, any rhythm disturbances it has detected and any therapy it has delivered since the last visit.

Long before the battery is ready to expire and long before the performance of the ICD changes in any way, an exam like this will show the doctor that the time is approaching to consider a replacement ICD. At that point, a brief hospital stay is arranged — typically no more than one or two days — to allow the doctor to remove the old ICD and replace it with a fresh one. Replacement procedures are often simpler than original implantations, and take the doctor and patient even less time.

How often will my doctor check my ICD?

Doctors vary in their opinions about this. Some say they prefer to see their ICD patients every two months or even more often when they feel the heart rhythm needs especially close observation. Others ask their patients to return every four to six months. This is more common among patients whose rhythms are quite stable.

Can people with defibrillators go near microwave ovens?

Yes. A number of years ago, when both ICDs and microwave ovens were made very differently, some ICDs reacted badly in the presence of old-style microwave ovens. As a result, ICDs were modified and are no longer affected by microwave ovens. This also is true for pacemakers. However, doctors advise ICD patients to avoid a few things, including:

  • Very powerful magnets, such as those you might find in a junkyard to lift discarded automobiles or contained within the cases of powerful stereo speakers. Smaller, weaker magnets — like those used to hold notes on a refrigerator or those in telephone receivers — pose no difficulty.
  • Very powerful electromagnetic fields generated by the equipment used for magnetic resonance imaging (MRI).
  • The electromagnetic field near an automobile ignition system.

The main concern is that a very strong electromagnetic field temporarily deactivates the ICD. This effect persists only as long as the patient is in the field, returning the ICD to full function as soon as you move away from the magnetism. However, your doctor doesn’t want your device’s operation suspended even briefly.

I broke up with him soon after the third shock, because when I imagined my future with him—being his wife and having his children—I only wanted to cry. I was too afraid of a coupled-up life that my heart could ruin. In hindsight, I know I was afraid of settling into a life with him by my side.

I started to spend my weekends at a rented shore house with my girlfriends. It was there that I met Tommy*.

Tommy was not my first kiss after John, but he was the first kiss that mattered. He helped me forget my fear.

I had been numb for months, and my attraction to him woke me up. I thought about him on the weekdays that dragged like the last period of school. On hot weekend nights, when I spotted him at the bar, his body short but strong, my stomach flipped.

He didn’t call or take me out. He only wanted a summer fling, but when he’d put his hand on my back, and press me to him, it didn’t matter. When his jokes cracked me up laughing, when he nicknamed me ‘Berly and held my hand as we walked home in a downpour—our feet splashing in puddles, our clothes heavy with rain—I didn’t think about the shock I always feared was looming. I only thought of him.

I was sleeping beside him one night when something woke me up. I couldn’t breathe, but I didn’t know why until the thudding in my chest told me. My heart was racing so fast, I couldn’t count the beats, and I knew a shock would fire soon.

I shook Tommy’s shoulder.

“Tommy, wake up. My defibrillator’s gonna go off.” I’d told him about my ICD before.

He looked at me with half his eyes.

“What’s going on?”

My heart felt as though it was ramming against my sternum. Tommy climbed one leg out of the jumbled gray blanket and then the other.

“I gotta go to the bathroom,” he mumbled as he slid off the bed.

I reached out and grabbed his wrist, the beating pounding in my ears.

“No, please, don’t go. Just sit with me.”

He slid away again, but I begged.

“Please. Just hold my hand.”

I slipped my hand into his, but his hand felt limp and uncomforting around mine.

My heart hammered and hammered. And then it hit. Time stood still as the shock thundered through me.

“Kim! What’s happening?” Tommy yelled out.

“I’m OK,” I said. “I’m OK.”

The lie hovered before my lips the way breath lingers in the cold. But it was made of less than air. It was made of nothing.

The next time I saw Tommy, he joked about what had happened. He made a buzzing noise as he pretended to shake. I laughed because it was wrong and ridiculous and funny. He was always funny. But it was not enough.

Still, we went home together, but we only talked. That night, he unexpectedly cuddled with me as we slept. When he rubbed my back and pulled me closer to him, I felt as though we were saying goodbye. A few weeks later, I heard about his new girlfriend; she was more than a summer fling. When I saw them together at a Halloween party, her smile confident and sure, I knew he was enough for her, and she for him.

When I met Anthony at 24, I didn’t know if anyone would be enough for me and my heart. Or maybe I was just afraid that someone would be.

“This Year’s Love” played in his Jeep on our first date, and I knew there was something there. I turned my face to the October wind and pushed the feeling away.

ICDs are useful in preventing sudden death in patients with known, sustained ventricular tachycardia or fibrillation. Studies have shown ICDs to have a role in preventing cardiac arrest in high-risk patients who haven’t had, but are at risk for, life-threatening ventricular arrhythmias.

Newer-generation ICDs may have a dual function which includes the ability to serve as a pacemaker. The pacemaker feature would stimulate the heart to beat if the heart rate is detected to be too slow.

View an animation of an ICD.

What is an Implantable Cardioverter Defibrillator (ICD)?

An ICD is a battery-powered device placed under the skin that keeps track of your heart rate. Thin wires connect the ICD to your heart. If an abnormal heart rhythm is detected the device will deliver an electric shock to restore a normal heartbeat if your heart is beating chaotically and much too fast.

ICDs have been very useful in preventing sudden death in patients with known, sustained ventricular tachycardia or fibrillation. Studies have shown that they may have a role in preventing cardiac arrest in high-risk patients who haven’t had, but are at risk for, life-threatening ventricular arrhythmias.

The American Heart Association recommends that before a patient is considered to be a candidate for an ICD, the arrhythmia in question must be life threatening and doctors have ruled out correctable causes of the arrhythmia, such as:

  • Acute myocardial infarction (heart attack)
  • Myocardial ischemia (inadequate blood flow to the heart muscle)
  • Electrolyte imbalance and drug toxicity

Because many people do not understand their underlying condition – such as heart failure or genetic predisposition for risk of sudden cardiac arrest – and because ICDs are used primarily to prevent sudden cardiac death, they in turn may not understand the benefits versus the limitations of having an ICD implanted. If you are one of those people, you will find information and guidance here.

Why do I need an ICD?

Your doctor may recommend an ICD if you or your child is at risk of a life-threatening ventricular arrhythmia because of having:

  • Had a ventricular arrhythmia
  • Had a heart attack
  • Survived a sudden cardiac arrest
  • Long QT syndrome
  • Brugada syndrome
  • A congenital heart disease or other underlying conditions for sudden cardiac arrest

How is an ICD implanted?

A battery-powered pulse generator is implanted in a pouch under the skin of the chest or abdomen, often just below the collarbone. The generator is about the size of a pocket watch. Wires or leads run from the pulse generator to positions on the surface of or inside the heart and can be installed through blood vessels, eliminating the need for open-chest surgery.

How does an ICD work?

It knows when the heartbeat is not normal and tries to return the heartbeat to normal.

  • If your ICD has a pacemaker feature when your heartbeat is too slow, it works as a pacemaker and sends tiny electric signals to your heart.
  • When your heartbeat is too fast or chaotic, it gives defibrillation shocks to stop the abnormal rhythm.
  • It works 24 hours a day.

New devices also provide “overdrive” pacing to electrically convert a sustained ventricular tachycardia (fast heart rhythm) and “backup” pacing if bradycardia (slow heart rhythm) occurs. They also offer a host of other sophisticated functions such as storage of detected arrhythmic events and the ability to perform electrophysiologic testing. Stored information can help your doctor optimize the ICD for your needs.

What should I ask my doctor or nurse about living with an ICD?

You most likely can resume a near normal lifestyle. But, it is best to ask your doctor what types of machines or equipment you should avoid. Also ask what you can and cannot do when you have an ICD. Read about living with an ICD.

Download ICD Questions to Ask Your Doctor for suggested questions for your healthcare providers, such as:

  • When can I resume normal activities?
  • Can I swim?
  • Can I run?
  • Can I have sex?
  • Can I play video games and use wireless devices?
  • What will the ICD feel like day to day?
  • When can I expect a shock?
  • Does the shock hurt?

AHA Recommendation

If you have an Implantable Cardioverter Defibrillator, be aware of your surroundings and the devices that may interfere with its operation. Potentially disruptive devices include those with strong magnetic fields. The following devices can disrupt the ICD’s signaling and prevent it from working properly, sometimes without your knowledge. The longer you are exposed to the potentially interruptive device and the closer it is in proximity to your ICD, the more likely it will affect your ICD’s performance.

Learn about electromagnetic compatibility of your ICD and other products with this list of devices that interfere with an ICD.

It’s not much of a support group for we are uncomfortable getting personal. I’m happy to talk to you about it. The past 10 years have definitely been a rollercoaster ride! Like many of us on this site I still don’t have an actual diagnoses. After my initial SCA I convinced myself it was a fluke, I was lucky to have survived, and it would never happen again. I got therapy for awhile, which helped me immensely, but I stopped worrying too much. Then a year and a half later I had another one. I passed out before I got shocked, but the dizziness just before was beyond anything I ever remember feeling. That SCA actually freaked me out more because now I knew it wasn’t a random thing that happened to me. I remember experiencing a lot of anxiety but over time it improved. Then everything was good for about 5 years. I was having a lot of anxiety on my job so I went to my primary doctor who prescribed something that turned out to be a huge mistake. 5 days after starting it I went into a v-fib storm. I got shocked I think 5 times overnight. I only felt 2. The other ones I apparently slept through or passed out. I spent a few days in the hospital, but the day after they released me I had 2 more. Now I was a complete basket case. When I finally got out of the hospital again I was afraid to go anywhere. I was checking my blood pressure constantly and when I did go out once in awhile I had panic attacks. I was taking an antidepressant and I had Ativan for anxiety. It took a few months but little by little I battled the anxiety. I learned to do a lot of positive self talk. Eventually I went back to work and did fine. Then this past year I decided to leave my husband. (That’s a whole other story.) The day I moved out I had 2 more incidents of v-fib. I ended up out of work for 6 months. The anxiety was a huge piece of that. I wasn’t having full blown panic attacks but I didn’t go out to stores or anything. So now it’s been about 9 months since my last incident. I’m doing great! I am a teacher so I’m retiring at the end of this school year. That should reduce a lot of stress!
The moral of my very long story is that the ups and downs happen. You almost have to just ride them out. With help, of course. If you feel anxious and depressed, consider therapy. Meds can help, too. But honestly, after going through it a few times, reminding myself I survived it before helps a lot. You will be OK. Let yourself accept being a bit depressed is normal. But then do what you need to to fight it. I know that sounds corny, but I really believe it. I’m happy to talk more if you ever want to.

Shocking Truths About Heart Defibrillators

Defibrillators are little devices that monitor every heartbeat, and when a defibrillator detects that a patient has gone into cardiac arrest it will immediately deliver a life-saving shock. But these shocks can sometimes happen for the wrong reasons — and do at a surprisingly high rate.

What does it feel like if one of these implanted defibrillators fires? My patients often describe a “shock” from their defibrillator as a bomb going off inside the chest. Most patients would gladly exchange this very short and intense burst of pain for extra years of life.

My colleagues and I studied this question (the results of our study were published in October 2013 in the Journal of the American College of Cardiology. We looked at what happened to 3,809 patients who received a shock from an implantable defibrillator. We then compared the outcomes of these 3,809 patients with 3,630 matched defibrillator patients who did not receive a shock.

Here’s what we found over the three-year follow-up period:

  • If the shock was to end a cardiac arrest (ventricular fibrillation), patients were 2.1 times more likely to die over the next three years.
  • If the shock was to stop ventricular tachycardia, a type of arrhythmia, patients were 1.7 times more likely to die over the next three years.
  • If the shock was from atrial fibrillation, patients were 1.6 times more likely to die over the next three years. It should be noted here that defibrillators are designed to not deliver a shock for atrial fibrillation. But if the atrial fibrillation is fast enough it can “fool” the defibrillator, and a shock will be delivered.
  • If the shock was for a very fast, benign arrhythmia or a device malfunction (the device was fooled), there was no increased risk of dying.

Interpreting the Defibrillator’s Shock

What do these findings mean? The majority of the time the defibrillators went off for the right reasons (ventricular tachycardia or ventricular fibrillation). But 41 percent of the shocks were because a device was fooled by a non-life-threatening arrhythmia, or because of a device malfunction.

Clearly, these devices aren’t doing a very good job if they fire for the right reason only 59 percent of the time.

First, in my opinion, this study should be a wake-up call for defibrillator manufacturers to create a more reliable device that is less likely to go off for the wrong reasons.

Second, if a patient receives a shock for any arrhythmia from the ventricles or for atrial fibrillation, this is a cry for help from the patient’s heart. These patients are at high risk of dying and need to be evaluated and treated quickly.

Often what we see is that these patients have gone into heart failure, or may have a blockage of one of the arteries in their heart. So patients who have received a shock for a ventricular arrhythmia or atrial fibrillation require prompt medical attention. With a thorough evaluation and treatment, including lifestyle changes, the heart may be given a chance to heal and reduce the risk of premature death.

Third, these results are reassuring in that there was no increased risk of death if the defibrillator went off for a benign rhythm or device malfunction. This also helps to answer the long-standing debate among cardiologists as to whether shocks, in and of themselves, are dangerous or not.

Fortunately, the danger is not from the shock but rather from the underlying cardiac condition.

At the end of the day, shocks, both appropriate and inappropriate ones, are just a part of implantable defibrillator therapy. It is my hope that from this study, device manufacturers will work to create better algorithms and software, so that these devices are not so easily fooled, and so that physicians caring for patients who have received a shock for ventricular fibrillation, ventricular tachycardia, or atrial fibrillation will realize the significance of this event and take rapid measures to prevent premature death in these patients.

RELATED: Why Defibrillators Are Risky for People With Atrial Fibrillation

Who Needs an Implantable Defibrillator?

Implantable defibrillators are reserved for patients who have either already survived a cardiac arrest or are at high risk for a cardiac arrest. Defibrillators are specifically designed to treat life-threatening arrhythmias in the ventricles, or the lower chambers of the heart.

Arrhythmias of the upper chamber of the heart, like atrial fibrillation, do not require an implantable defibrillator.

What Is It Like to Live With a Defibrillator?

While these implanted devices generally don’t cause much discomfort, patients can certainly feel them under the skin. If a person is wearing a swimming suit, you can see the outward bulge of the defibrillator device on their chest.

These devices help many patients feel more secure because they know that every heartbeat is being monitored. But for other patients it can be a huge source of anxiety, since they never know whether the device is going to deliver a shock.

Unfortunately, these devices aren’t foolproof: Sometimes a patient will receive a shock for a non-life-threatening event or a device malfunction, as our study demonstrated.

John D. Day, MD, is a cardiologist specializing in heart rhythm disorders at the Intermountain Medical Center Heart Institute. He is the immediate past president of the Heart Rhythm Society and is the editor-in-chief of the Journal of Innovations in Cardiac Rhythm Management. He has published more than 100 medical articles and has an upcoming book entitled The Longevity Plan: Seven Lessons From the World’s Happiest and Healthiest Village.

PHOTO CREDIT: Apogee Apogee/Getty Images

— — Question: If my defibrillator fires does that mean it just saved my life from a life threatening heart rhythm problem?

Answer: If your defibrillator has gone off, whether you felt it or not, whether you’ve lost consciousness and were told that a shock occurred or whether you feel the shock, there’s a good chance that it operated appropriately and shocked in response to a lethal rhythm. That’s more likely the case if indeed you were losing consciousness or had lost consciousness.

Occasionally, a defibrillator will shock for an inappropriate reason. That can be a high heart rate such as sinus tachycardia or the rhythm that happens when you exercise or another non-lethal arrhythmia may reach the rate cutoff such that the device — which can’t really tell the difference between a bad fast rhythm and a not so bad fast rhythm — the device would go ahead and apply a shock.

Another possible cause for a shock is if there’s a malfunction in the device. While this is uncommon in terms of the device itself, or occasionally will occur with a lead problem such that it over senses and then the device thinks there’s an abnormal fast heart rhythm and a shock is delivered.

Whenever a shock does occur, it’s a good idea to go ahead and call your doctor and let your doctor’s office know what happened. If it’s the first time it’s ever gone off, then it might make sense to call anytime day or night. But certainly if there’s been multiple shocks, two shocks in a row, that’s considered really an emergency and should prompt you to get urgent medical attention.

One study cited by Russo shows that even among patients with a do-not-resuscitate order, or DNR, discussions between doctors and patients about what could happen with an ICD at the end of life occurred in fewer than 45 percent of cases.

Talk about it on the Vitals Facebook page

While it might be hard to suggest a dying patient turn off an ICD, it might make sense to include this discussion at the time the device was being implanted. But another study showed that only 4 percent of doctors were routinely discussing the issue with patients before the ICD was implanted.

Other studies showed that physicians were more comfortable talking about DNRs than they were about the possible impact of a turned-on ICD at the end of life. Many indicated that they would prefer that the patient -– or the patient’s family –- bring the subject up. “One cardiologist said she feared that talking about deactivation with patients would be like ‘shutting off hope,’” Russo noted.

Even if patients and families aren’t ready to completely turn off an ICD, the device can be reprogrammed so that it works more like a pacemaker, delivering tiny jolts of electricity rather than the high-voltage shock that completely recalibrates the heart.

Ultimately, Russo hopes that by writing the paper he’ll spur more discussions. “Regardless of a provider’s comfort level with the subject, patients have a right to be informed of all treatment options, including ICD deactivation,” he concluded.

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