Modern pacemakers are essentially silent during normal operation, but there are real scenarios where you or someone nearby can hear sounds associated with one. Some of these sounds are deliberate alarms engineered into the device, while others arise from the device’s interaction with surrounding tissues. The distinction matters, because some pacemaker-related sounds are harmless curiosities and others are urgent signals that something has gone wrong.
The Device Itself Is Usually Silent
A normally functioning pacemaker sends tiny electrical impulses to the heart muscle. These impulses are far too small to produce any audible vibration or mechanical noise on their own. Unlike a mechanical watch or a pump with moving parts, a pacemaker is a solid-state electronic device with no gears, no motors, and no components that physically shift position during routine pacing. Most people with pacemakers go years without ever hearing anything from the device.
That said, “pacemaker” in everyday conversation often covers a range of implanted cardiac devices, including implantable cardioverter-defibrillators (ICDs), which pace the heart but can also deliver high-energy shocks to stop dangerous rhythms. ICDs have features that pacemakers alone may not, including built-in audible alarms. When people report hearing their device, they are frequently describing one of these alarm tones rather than the sound of the device pacing.
Built-In Audible Alarms and What They Mean
Many ICDs and some newer pacemakers contain a small speaker or piezoelectric element that can emit a beeping tone the patient is meant to hear and act on. These alarms are not accidental. They are programmed to alert you to specific problems the device has detected internally.
One well-known example is the lead integrity alert, an automated algorithm designed to catch problems with the wire (lead) connecting the device to the heart before those problems cause a failed or inappropriate shock. The alert activates when the device detects a combination of warning signs, such as a sudden change in the electrical resistance of the lead and abnormal patterns of rapid heart-rate sensing. Once triggered, the device sounds an audible tone immediately and repeats it every four hours until the issue is addressed by a clinician.1Indian Pacing and Electrophysiology Journal. Audible alarm from an implantable cardioverter defibrillator- unravelling the cause – Section: Lead integrity alert (LIA) The idea is straightforward: even if you miss the first alert, the repeated beeping eventually gets your attention and sends you to your cardiologist for a device check.
These audible alarms can also be triggered by low battery voltage, abnormal lead impedance patterns suggesting insulation damage or a fractured wire, or loss of communication with a remote monitoring system. In devices with wireless telemetry, the alert often works in tandem with a remote notification sent to your clinical team, but the audible tone serves as a backup in case the wireless transmission fails or is not set up.2Indian Pacing and Electrophysiology Journal. Unexpected inhibition of bradycardia pacing due to oversensing in ICD lead fracture associated with spurious tachyarrhythmia detection and discharges – Section: Discussion
If you hear a repetitive beeping or chirping sound coming from the area of your implanted device, that is one of the clearest “call your clinic now” signals you can get. These tones are not subtle background noise. They are deliberately pitched to be noticeable, even through clothing and skin. Some patients describe them as similar to a smoke detector’s low-battery chirp. It is not an emergency in the sense that you need to call 911 in most cases, but it does mean something needs clinical attention within hours to days, not weeks.
Sounds the Body Makes Because of the Device
Beyond electronic alarms, a pacemaker or ICD can produce audible or palpable effects through its interaction with the tissues around it. These fall into a few distinct categories.
Valve Clicks and Murmurs
The lead of a conventional pacemaker passes through a vein, into the right side of the heart, and anchors in the heart muscle. Along the way, it threads through or near the tricuspid valve, which sits between the right atrium and right ventricle. In some patients, the lead physically interferes with the valve’s ability to close normally. This can produce new heart sounds: clicks during the cardiac cycle, sometimes followed by a murmur that a doctor can hear with a stethoscope. One documented pattern involves a late-systolic murmur preceded by clicks, heard loudest along the left side of the breastbone, that increases with inspiration and standing. These findings can point to tricuspid regurgitation caused by the lead, and in at least one reported case, removing the lead made the sounds disappear entirely.3PubMed. Presumptive tricuspid valve malfunction induced by a pacemaker lead: a case report and review of the literature
You are unlikely to hear these valve sounds yourself without a stethoscope, but your doctor might pick them up during a routine exam. If you are told you have a new murmur after pacemaker implantation, lead-related valve interference is one of the things your cardiologist will consider.
Muscle Twitching Near the Device
Pacemakers deliver electrical energy to the heart, but that energy can sometimes stimulate nearby muscles instead of, or in addition to, the heart. This is called extracardiac stimulation, and it can affect the pectoral muscles (the chest muscles near where the device sits), the intercostal muscles between your ribs, or the diaphragm. Common culprits include a lead that has shifted out of its ideal position, insulation damage on the lead, or a device configured in a way that allows current to spread beyond the heart.4International Journal of the Cardiovascular Academy. A case of twitching on the pacemaker pocket – Section: Abstract
The result is visible or palpable twitching in the chest wall, synchronized with each pacing pulse. Some patients feel it as a rhythmic fluttering or thumping under the skin near the device pocket. Others can actually see the skin jump. While not dangerous by itself, it can be uncomfortable, and it often signals a lead or insulation problem that needs to be fixed. If the twitching is new or suddenly worse, it warrants a device check.
Phrenic Nerve Stimulation and Hiccup-Like Sensations
A particularly bothersome variant of extracardiac stimulation involves the phrenic nerve, which controls the diaphragm. When a pacing lead sits close to the phrenic nerve, the electrical pulse can cause the diaphragm to contract with each heartbeat, producing a sensation that patients often describe as rhythmic hiccups or a pulsing feeling in the abdomen. It can be subtle at certain body positions and very obvious at others.
Research using acoustic cardiography, which combines heart-sound analysis with the electrocardiogram, has shown that phrenic nerve stimulation can be detected and its effects on how well the heart pumps blood can be measured. In a study of 42 patients, phrenic nerve stimulation was induced through pacing at various locations in the heart, and the resulting diaphragm contractions were confirmed by fluoroscopy or by the patient’s symptoms.5PubMed. Detection and hemodynamic significance of cardiac pacemaker-induced phrenic nerve stimulation The stimulation is not just annoying; in some cases it actually reduces the heart’s pumping efficiency because the diaphragm contractions interfere with normal chest pressure dynamics.
If you develop a rhythmic hiccupping or abdominal twitching that seems to match your pulse, especially if it started after a new device was implanted or a lead was repositioned, phrenic nerve stimulation is the likely explanation. It is usually fixable by reprogramming the device to reduce the energy output on the offending lead or by adjusting which electrode the device uses for pacing.
Lead Displacement and Twiddler’s Syndrome
Sometimes the sounds or sensations from a pacemaker change because the lead has physically moved. One unusual but well-documented cause of lead displacement is twiddler’s syndrome, in which the patient subconsciously or deliberately rotates the pulse generator inside its pocket under the skin. This rotation winds the lead around the device like thread on a spool, gradually pulling the lead tip out of position in the heart.6PubMed. Pacemaker-twiddler’s syndrome: a rare cause of lead displacement and pacemaker malfunction
The consequence is pacemaker malfunction: the device may fail to pace the heart, or it may pace the wrong tissue entirely, producing muscle twitching, diaphragm stimulation, or ineffective cardiac pacing. Twiddler’s syndrome is uncommon, but it tends to occur in the first few months after implantation, before the device pocket has fully healed and scarred into place.7PubMed Central. The pacemaker-twiddler’s syndrome: an infrequent cause of pacemaker failure – Section: BACKGROUND Patients who fidget with or touch the device site are at higher risk. If you notice the device feels like it has shifted or rotated, or if pacing sensations change abruptly, that is worth reporting promptly.
Remote Monitoring and Smartphone Alerts
The trend in cardiac device management has been moving away from relying solely on audible beeps from the device and toward remote monitoring systems that send data from the implant to your clinical team automatically. Traditionally this required a bedside console, a small box you keep at home that wirelessly reads data from your device overnight and transmits it to the clinic. If the system detected a problem, the clinical team would contact you.
Studies of remote monitoring in patients with known lead problems have shown real benefits. In one analysis of patients with a recalled ICD lead, those on home monitoring had a lower rate of symptomatic lead failure events, including inappropriate shocks and loss of pacing due to electrical noise on the lead, compared to patients followed only with in-office visits.8Oxford Academic (EP Europace). Potential role of home monitoring to reduce inappropriate shocks in implantable cardioverter-defibrillator patients due to lead failure – Section: Results The monitoring system catches problems earlier, often before the device’s own internal alarm would trigger.
Newer-generation devices have gone a step further by using Bluetooth to communicate directly with a smartphone app, eliminating the need for a separate bedside console altogether. The app runs on the patient’s own phone or tablet and can relay device data to the clinic without any additional hardware.9PubMed Central. Performance of first pacemaker to use smart device app for remote monitoring – Section: Background For patients, this means alerts about device status might arrive as a push notification on your phone rather than as a beep from your chest. It also means that if you hear a sound from your device, it may genuinely be an urgent tone that the remote system could not handle on its own, making it all the more important to respond.
Phantom Shocks and Anxiety-Driven Perceptions
Not every sound or sensation a patient attributes to their device is actually coming from the device. People who live with ICDs sometimes report feeling shocks when their device records show no shock was delivered. These phantom shocks are a recognized phenomenon and can be deeply distressing. Research involving patients who reported phantom shocks found three recurring themes in their experiences: the sensation felt physically real, it carried significant emotional weight, and patients spent considerable mental energy trying to figure out what had happened. Both patients who experienced phantom shocks and those who experienced real shocks showed elevated levels of trauma-related distress and anxiety.10PubMed. Uncovering phantom shocks in cardiac patients with an implantable cardioverter defibrillator – Section: RESULTS
This does not mean the experience is “made up.” Phantom shocks appear to involve the brain replaying or anticipating the sensation of a real shock, often triggered by anxiety, muscle spasms, or benign palpitations that the patient interprets as a device firing. If you feel what seems like a shock but your device interrogation later shows nothing happened, it is worth discussing with your cardiologist and potentially with a psychologist experienced in cardiac device issues. Cognitive behavioral therapy has shown promise in reducing phantom shock frequency and the anxiety that fuels them.
Pocket-Site Sensations That Are Not Sounds
Patients sometimes describe feelings at the device pocket site that are not exactly sounds but get lumped into the same worry. A sense of warmth, mild aching, or awareness of the device sitting under the skin is common in the first weeks after implantation and usually fades as the tissue heals. What should get your attention is sudden swelling over the device. Subcutaneous hematoma, where blood collects around the device, is a known complication of implantation and can cause a visible bulge, tenderness, and sometimes a feeling of pressure or fullness under the skin. Most small hematomas resolve on their own, but larger ones may need to be drained.11PubMed Central. An atypical pacemaker pocket hematoma containing chyliform fluid Redness, warmth, and fever over the pocket site raise the possibility of infection, which is a genuine emergency requiring immediate medical attention.
A Practical Guide to When to Worry
Given the range of things you might hear, feel, or notice, it helps to have a rough mental framework for sorting them.
- Repetitive beeping or chirping from the device: This is almost certainly an intentional alarm. Contact your device clinic within the day. It may indicate a lead problem, low battery, or another issue the device has detected internally.
- Rhythmic twitching near the device or in your abdomen: Likely extracardiac stimulation of the chest muscles or diaphragm. Not immediately dangerous, but it can signal a lead issue and should be checked at your next available appointment, or sooner if it is severe or new.
- A new heart murmur or clicking sound your doctor hears: May reflect lead interaction with the tricuspid valve. Your cardiologist will decide whether imaging or a lead adjustment is needed.
- A sensation that the device has shifted or rotated in its pocket: Could indicate twiddler’s syndrome or early lead displacement. Report it before it causes a pacing failure.
- A feeling of shock with no event recorded on the device: Likely a phantom shock. Distressing but not dangerous in itself. Discuss it with your care team, especially if it is causing significant anxiety.
- Sudden swelling, redness, warmth, or drainage at the pocket site: Possible hematoma or infection. Seek same-day evaluation, especially if you have a fever.
The general principle is that any new, unexplained change in what you hear or feel from your pacemaker area deserves a call to your device clinic. Most of the time the explanation turns out to be benign or easily fixable. But the small fraction of cases where it signals a lead fracture, an insulation break, or an infection are serious enough that it is never worth ignoring. Your device is designed to help keep you safe, and part of that design includes giving you signals when something needs human attention.