No. A pacemaker sends tiny electrical pulses that most people never feel, and it doesn’t shock you.1ABC News. Can I Tell That A Pacemaker Is Working, Will I Feel It And Is It Uncomfortable? The confusion comes from a close cousin, the implantable defibrillator, which is built to deliver a real shock when the heart goes into a dangerous rhythm.2UC San Diego Health. Living with a Pacemaker or ICD So whether you’ll ever feel a jolt depends mainly on which device you have, not on whether you have a heart device at all.
What You Actually Feel When a Pacemaker Works
Each pacing pulse lasts a fraction of a thousandth of a second, often around 0.2 to 0.3 thousandths.3PubMed. Pulse duration variation and electrode size as factors in pacemaker longevity That is far too brief and small to feel like an electric jolt. A pacemaker can speed up a slow rhythm, help control a fast one, and keep the heart’s chambers working together.4MedlinePlus. Pacemakers and Implantable Defibrillators
Part of the reason a pulse inside the heart doesn’t hurt is that heart tissue has far fewer pain-sensing nerve endings than skin. What people notice, if anything, is the heartbeat itself, such as a pause ending or a beat arriving on time, not the electricity that triggered it. Most pacemakers fire only when the heart needs help, so many people go long stretches with nothing to notice. The improvement often shows up as less tiredness and dizziness rather than as a sensation.
The fear has some history behind it. The first external pacemakers used electrodes strapped to the chest and very high voltages, and patients found the repeated shocks painful and their skin irritated.5Understanding Animal Research. History of the Pacemaker Modern devices sit inside the body and touch the heart directly, so they need a tiny fraction of that energy.
Some people do feel changes in heart rate or rhythm when the pacemaker starts or stops pacing.6ABC News. Can I Tell That A Pacemaker Is Working, Will I Feel It And Is It Uncomfortable? You may notice a steadier or faster beat, especially when it kicks in after a pause.7ABC News. Can I Tell That A Pacemaker Is Working, Will I Feel It And Is It Uncomfortable? These sensations are usually not painful.8ABC News. Can I Tell That A Pacemaker Is Working, Will I Feel It And Is It Uncomfortable?
Other sensations have different causes. Soreness, bruising, or tenderness at the incision in the first weeks comes from the surgery, not the pulses, and the device itself can feel like a firm lump under the skin, which is normal. Pounding, a “flicking” feeling in the chest, or chest pressure is different. Those warrant a call to the doctor rather than being assumed normal.9WomenHeart Connect. Feeling my pacemaker pacing
The Device That Does Shock, The ICD
An ICD (implantable cardioverter defibrillator) monitors the heart and, if it senses a dangerous rhythm, delivers a shock.10MedlinePlus. Pacemakers and Implantable Defibrillators It is designed to stop very fast rhythms like ventricular tachycardia or ventricular fibrillation, which can kill within minutes.11UC San Diego Health. Living with a Pacemaker or ICD Pacemakers, by contrast, mainly treat hearts that beat too slowly.12UC San Diego Health. Living with a Pacemaker or ICD Gentle pacing alone can’t fix a fast, chaotic rhythm. The shock resets the heart’s electrical activity, which is why doctors recommend ICDs for people at high risk of sudden cardiac arrest.
Most defibrillators can also pace, so an ICD owner gets both gentle pulses and the possibility of a shock. An ICD is built around a larger battery and a capacitor that stores up energy, which is what lets it deliver a strong shock when needed. Some ICDs first try a faster burst of painless pacing to stop a fast rhythm, and deliver a shock only if that fails, so not every treatment is a jolt.
Some heart-failure devices combine pacing with a defibrillator, while others pace only.13PubMed Central. CRT-D or CRT-P in CRT-indicated patients? If you’re unsure which you have, your device ID card names the maker and model and usually says pacemaker or defibrillator. “ICD,” “CRT-D,” or “defibrillator” means it can shock. “CRT-P” or plain “pacemaker” means pacing only. Your device clinic can confirm at any check.
Twitching, Hiccups and Muscle Jumps From a Pacemaker
Pacing can sometimes stray outside the heart and cause involuntary twitching of chest, rib, or diaphragm muscles.14OSP Journal of Case Reports. Right Hemi-Diaphragmatic Twitching: A Case of Atrial Lead Displacement into the Superior Vena Cava and Review of Literature You may feel rhythmic hiccups, shortness of breath, twitching in time with your heartbeat, or a general sense of being unwell.15OSP Journal of Case Reports. Right Hemi-Diaphragmatic Twitching: A Case of Atrial Lead Displacement into the Superior Vena Cava and Review of Literature It can come and go or be constant, and it can be quite uncomfortable.16OSP Journal of Case Reports. Right Hemi-Diaphragmatic Twitching: A Case of Atrial Lead Displacement into the Superior Vena Cava and Review of Literature
A nerve that controls the diaphragm runs close to parts of the heart where a lead, the wire carrying pulses, may sit.17PubMed Central. Sudden onset pacemaker-induced diaphragmatic twitching during general anesthesia A wire placed near it, or one that has moved, can trigger diaphragm twitching.18PubMed Central. Sudden onset pacemaker-induced diaphragmatic twitching during general anesthesia About 30% of people with heart-failure pacemakers that pace the left side have some diaphragm stimulation, though it bothers only 3% to 26% of them.19PubMed Central. Phrenic nerve stimulation, a rare complication of pacemaker Twitching right over the device itself can sometimes mean a damaged coating on the wire.20International Journal of the Cardiovascular Academy. A case of twitching on the pacemaker pocket
Pacing twitches usually keep time with your heartbeat, so checking your pulse while one is happening can be a useful clue. Random eyelid or leg twitches are unrelated. Note when it started and which positions trigger it, and tell your clinic.
A twitch can appear weeks after the device was working fine. The wire can shift slightly in the first weeks before scar tissue anchors it, which may bring it closer to the diaphragm nerve. Bending forward or lying on one side can also change how close the nerve is to the wire, so the twitching may appear only in certain postures.
A doctor or technician can change settings without surgery, using an external programmer held over the device.21Summit Healthcare. Pacemaker Adjustment and Malfunction Symptoms, Summit Healthcare The strength of each pulse can be turned down so it still captures the heart but no longer reaches the nerve. In devices that pace the left side, technicians can sometimes choose a different electrode on the wire, moving the point of stimulation away from the nerve. The clinic usually tests with you sitting or lying in several positions to confirm the twitching has stopped and the heart is still paced reliably.
A visit is simple. A wand or wireless link reads the device, staff may test its outputs and ask whether you feel twitching, and adjustments take minutes. You can usually leave the same day. A wire that has moved may still need a procedure to reposition it.22OSP Journal of Case Reports. Right Hemi-Diaphragmatic Twitching: A Case of Atrial Lead Displacement into the Superior Vena Cava and Review of Literature
What an ICD Shock Feels Like
Most people rate the shock as severe, with nearly 8 in 10 scoring it 3 to 5 on a 5-point scale.23PubMed. Patients’ attitudes toward implanted defibrillator shocks Common descriptions are a blow to the body or a spasm that makes the whole body jump.24PubMed. Patients’ attitudes toward implanted defibrillator shocks Some people feel surprised, while others sense warning changes inside them first.25PubMed. The experiences of patients electrically shocked by an implantable cardioverter defibrillator: Findings from a descriptive qualitative study Shocks can leave physical and emotional after-effects.26PubMed. The experiences of patients electrically shocked by an implantable cardioverter defibrillator: Findings from a descriptive qualitative study Getting used to it over time is common for some people.27PubMed. The experiences of patients electrically shocked by an implantable cardioverter defibrillator: Findings from a descriptive qualitative study
Whether you were conscious matters. Some people get a few seconds of dizziness or palpitations beforehand. Others pass out from the dangerous rhythm and feel only the aftermath, and someone shocked during sleep may be woken with no warning at all. Afterward you may feel shaky, tired, or sore in the chest muscles for a while, even once the rhythm has settled.
Not every shock is needed. In one large group of ICD patients, about 1 in 9 had at least one unnecessary shock, and about 3 in 10 of all shocks were unneeded.28PubMed. Inappropriate implantable cardioverter-defibrillator shocks in MADIT II: frequency, mechanisms, predictors, and survival impact The most common triggers were atrial fibrillation and other fast but non-dangerous rhythms, followed by sensing errors.29PubMed. Inappropriate implantable cardioverter-defibrillator shocks in MADIT II: frequency, mechanisms, predictors, and survival impact A damaged wire or electrical interference can also cause them.30PubMed Central. Inappropriate ICD Shocks for Inappropriate Reasons
Careful programming and medicines can cut shocks while keeping the lifesaving protection.31PubMed. Evaluation and management of patients after implantable cardioverter-defibrillator shock You can ask your doctor whether your settings can be adjusted to avoid treating harmless fast rhythms, and whether medicines that calm rhythm problems would help. Treating atrial fibrillation may also lower your risk of unneeded shocks.
Phantom Shocks and the Fear of Being Shocked
A phantom shock is the sensation of an ICD shock when the device didn’t fire. Estimates range from 2% to about 25% of ICD owners, averaging about 7%.32PubMed Central. Incidence, Risk Factors and Predictors of Phantom Shocks in Patients with Implantable Cardioverter Defibrillators: State-of-the-art Review People with phantom shocks have more depression and anxiety.33PubMed. Psychological indices and phantom shocks in patients with ICD The fear can lead to avoiding going out at all, and even post-traumatic stress.34PubMed Central. Understanding Phantom Shocks in Implantable Cardioverter-Defibrillator Recipients
It feels real, and often wakes people at night. It tends to follow a real shock or intense worry about one. Muscle twitches or a strong palpitation can resemble a shock, especially in someone watching for one. Treating anxiety can reduce these episodes, and support groups help many device owners.
Your clinic can read the device’s memory to see whether a shock actually happened. Report any suspected shock, even when the log shows none, because the report can open the door to help. Ask about counseling or support if fear is affecting daily life.
What to Do After an ICD Shock
After one shock, if you feel fine, sit down and contact your device clinic the same or next day. The clinic can read the device’s record to see what triggered it and whether it was needed, which guides any changes to treatment.
If you get two or more shocks close together, or chest pain, fainting, or breathlessness, call emergency services. Repeated shocks with an abnormal rhythm need urgent rhythm treatment.35Medical Research Journal. Pre-hospital management of patients with implantable cardioverter-defibrillators shocks — procedure proposal Emergency teams can place a magnet over the ICD to switch off its shocks if it is misfiring.36Medical Research Journal. Pre-hospital management of patients with implantable cardioverter-defibrillators shocks — procedure proposal When you call the clinic, have ready the time of the shock and what you were doing, any symptoms before or after, your device ID card, and a home monitor transmission if your clinic uses one. Make sure family know the difference between one shock and repeated shocks, have your clinic and emergency numbers, and can find your ID card.
Can Someone Touching You Get Shocked
Someone touching you during an ICD shock may feel a tingle or muscle spasm,37Medtronic. Does it hurt to receive a shock from an implantable cardioverter defibrillator (ICD) but it won’t hurt them.38Sudden Cardiac Arrest UK. ICD Shocks: What you need to know The energy is delivered inside the chest and almost all of it stays within the body. Even with external defibrillators, which use far more energy, the risk to a rescuer touching the patient is likely minimal.39PubMed Central. Risk assessment of electric shock to the general public without Personal Protective Equipment during defibrillation shock delivery: A simulation study Partners, carers, and children can stay close and help without fear.
Pacemaker pulses are too small to pass any sensation to others. Intimacy and hugging are safe, and others can perform CPR on you if needed.
Phones, Pools and Other Interference
Mobile phones may interfere if held over the device side.40PubMed Central. Electromagnetic interference on pacemakers. Use the ear on the opposite side and don’t keep the phone in a chest pocket over the device. A phone in use or ringing is the issue, so one sitting in a bag or on a table is no concern. If you notice dizziness or odd heartbeats while using a phone, move it away and tell your clinic. Some older single-wire pacemaker systems can pick up chest muscle signals during hard exercise.41PubMed Central. Electromagnetic interference on pacemakers. MRI scans need special planning, so always tell staff about your device beforehand.42PubMed Central. Electromagnetic interference on pacemakers.
Microwaves, TVs, and most household appliances in good working order are generally safe at normal use. Walk through store and airport security without lingering, show your ID card, and ask for a hand search if worried. For tools like welders, check your device maker’s guidance.
Tiny electrical leaks can mimic a dangerous rhythm to an ICD.43PubMed Central. Inappropriate Implantable Cardioverter-Defibrillator Shocks Attributed to Alternating-Current Leak in a Swimming Pool In one reported case a man got 2 unneeded shocks probably from current leaking in a swimming pool.44PubMed Central. Inappropriate Implantable Cardioverter-Defibrillator Shocks Attributed to Alternating-Current Leak in a Swimming Pool If you get a shock in water or near an appliance, move away and report it.