Cardiac Devices: Types, How They Work, Risks and Recovery
Updated: 6 days ago
Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 31, 2026 · How we review
Quick Answer: What is a cardiac device?
A cardiac device is a small machine placed in the chest to help the heart beat in a steady rhythm or pump blood better. The main types are pacemakers, biventricular pacemakers, implantable cardioverter defibrillators (ICDs) and ventricular assist devices (VADs). They treat arrhythmias and heart failure and help protect against cardiac arrest. [1]
What the research says
An ICD lowered the risk of death in people with heart failure. In a trial of 2,521 adults with heart failure and a weak heart pump (ejection fraction 35% or less), 22% of those with an ICD died during follow-up versus 29% on placebo — a 23% lower risk of death. (Bardy et al., N Engl J Med, 2005)
A heart pump (LVAD) nearly halved the risk of death in end-stage heart failure. Among 129 people who could not get a heart transplant, the device cut the risk of death by 48%; one-year survival was 52% with the pump versus 25% with medicines alone. Serious side effects such as infection and bleeding were more common with the device. (Rose et al., N Engl J Med, 2001)
MRI scans were safe for most people with older pacemakers and ICDs when a safety protocol was followed. In 1,509 patients who had 2,103 MRI scans, there were no long-term serious problems; the device briefly reset in only 0.4% of scans. (Nazarian et al., N Engl J Med, 2017)
Key takeaways
A cardiac device is a small machine that helps your heart keep a regular rhythm, avoid cardiac arrest or pump blood.
Pacemakers fix slow or irregular beats; ICDs shock a dangerously fast rhythm; VADs pump blood when the heart is too weak.
The battery in most devices lasts 6 to 15 years.
Phones, microwaves and security scanners are generally safe. MRI is usually possible, with extra safety steps.
Plan on a device check at least once a year, and call your doctor about fever, dizziness, palpitations or changes at the incision.
What is a cardiac device?
A cardiac device is a small machine a doctor places in your chest to help your heart work better. Some devices keep your heartbeat steady. Others protect you from cardiac arrest or help your heart pump blood to your body. [1]
These devices go through official safety reviews before doctors can use them. Having a machine in your chest can feel unsettling at first. Yet millions of people rely on cardiac devices to feel better and live longer.
What are the main types of cardiac devices?
The four main cardiac devices are the pacemaker, the biventricular pacemaker, the implantable cardioverter defibrillator (ICD) and the ventricular assist device (VAD). Each one solves a different heart problem. [1]
Cardiac devices at a glance
Device | What it does | Where it connects | Main goal |
Pacemaker | Tells the heart muscle when to contract (pump) | A lead usually goes to the lower right chamber (right ventricle) | Fix a slow or irregular rhythm |
Biventricular pacemaker | Helps the lower chambers pump together | Leads touch both lower chambers and the right upper chamber | Restore coordinated pumping |
ICD | Shocks the heart when the rhythm is too fast | Leads in the heart tissue | Prevent sudden cardiac death |
VAD | Pumps blood from the heart to the body | Attaches to a lower chamber, most often the left; battery stays outside the body | Support a weak, failing heart |
What does a pacemaker do?
A pacemaker tells your heart muscle when to pump. Its wire, called a lead, usually sits in the lower right heart chamber. Some newer pacemakers have no wire at all — these leadless pacemakers attach directly to the right ventricle.
What does a biventricular pacemaker do?
A biventricular pacemaker helps both lower heart chambers pump at the same time. Its leads touch both lower chambers and the right upper chamber. This is useful when the two sides of the heart beat out of step, a problem called ventricular dyssynchrony.
What does an ICD do?
An implantable cardioverter defibrillator (ICD) shocks your heart back into a normal rhythm when it beats dangerously fast. Correcting that rhythm helps protect you from sudden cardiac arrest and sudden cardiac death.
What does a ventricular assist device do?
A ventricular assist device (VAD) is a pump that helps your heart move blood to the rest of your body. It can support the left side, the right side or both, but most often the left. Read our full guide to ventricular assist devices for more detail.
Who needs a cardiac device?
A cardiac device is recommended for people whose heart rhythm or pumping is not working well enough on its own. Your doctor may suggest one if you have: [1]
Condition | What it means |
Irregular heart rate | The heartbeat is uneven — see our heart arrhythmia guide |
Electrical signals are slowed or blocked | |
The heart's natural signal source misfires | |
Long QT syndrome | The heart takes too long to recharge after each beat |
Tachycardia | The heart beats too fast |
The heart beats too slowly | |
Ventricular fibrillation | A life-threatening chaotic rhythm — see ventricular arrhythmia |
Heart failure | The heart cannot pump enough blood |
Cardiomyopathy | The heart muscle is diseased |
How does a cardiac device work?
A cardiac device works by sensing what your heart is doing and stepping in when the rhythm or pumping goes wrong. For a pacemaker or ICD, the doctor places thin wires (leads) from the device into your heart tissue. [1] [2]
That contact lets the device "listen" to each heartbeat. When needed, it sends a small electric impulse to make your heart beat. An ICD can also send a shock if the rhythm becomes dangerously fast.
Here is what happens behind the scenes:
It follows a program. Your doctor sets the device's program from outside your body.
It runs on a long-lasting battery. A small battery powers the device for years.
It can report to your care team. Many devices send data by phone or internet, so your doctor can spot changes early without frequent visits.
A VAD works differently. One part attaches to a lower heart chamber, while another part — including the battery — stays outside your body. The pump takes over much of the workload from your heart muscle.
What are the benefits of cardiac devices?
Cardiac devices can protect your life, ease symptoms and keep you out of the hospital. The main benefits are: [1]
Lifesaving protection from cardiac arrest
Better blood circulation
A more regular heart rhythm
Fewer symptoms from rhythm problems
Fewer hospital stays due to heart problems
A minimally invasive procedure for some device types
Battery life that can last 6 to 15 years
What are the risks of cardiac devices?
Cardiac devices and the procedures to place them carry some risks, though most people do well. Possible complications include: [1]
Risk group | Possible complications |
From the procedure | Bleeding, a small puncture in the heart, a collapsed lung (pneumothorax), a collection of blood (hematoma), blood clots |
From the device | Broken lead wires, device malfunction, the device moving out of place |
Longer term | Infection related to the device, cardiomyopathy |
Talk with your doctor about your personal risk before the procedure.
What is recovery like after getting a cardiac device?
Recovery after a cardiac device usually starts right away, because the device begins working as soon as your doctor finishes setting it up. Your care team may adjust its settings before or after you leave the hospital. [1]
Some devices are short term. For example, a VAD may support you while you wait for a heart transplant. Others, like pacemakers and ICDs, are meant for the long term.
During recovery:
Follow your doctor's instructions for caring for your incision.
Limit physical activity for a while, as advised.
Ask your doctor when you can return to work and start driving again.
Stay in touch with your care team so they know how the device is working for you.
Can you have an MRI with a cardiac device?
Most people with a cardiac device can have an MRI, but your care team needs to confirm it is safe for you first. Before any scan, tell your doctor and the imaging staff about your device so they can take special safety steps. [1] [5]
Is it safe to use phones and go through security with a cardiac device?
Using phones and going through security is generally safe with a cardiac device, but keep cell phones and other items with strong magnets at least 6 inches (15 cm) from your device, don't carry them in a pocket over it, and walk through security scanners without lingering. [1]
When should you call your doctor about a cardiac device?
You should call your doctor after a cardiac device procedure if you notice fever or chills, pain that medicine does not ease, dizziness, palpitations, or changes near the incision. If your ICD gives a shock, contact your care team; call 911 if you get more than one shock in a short time or a shock with chest pain, trouble breathing or fainting. [1]
Fever or chills (possible infection)
Pain that does not get better with medicine
Dizziness
Warmth, swelling, color change or unusual bleeding near the incision
You will also need a device check at least once a year, with more visits at first. And you can contact your care team any time something does not feel right with the device in your chest.
Conclusion
Cardiac devices are one of the most effective tools modern medicine has for heart rhythm problems and heart failure. A pacemaker keeps a slow heart on beat, an ICD stands guard against a dangerous fast rhythm, and a VAD helps a weak heart pump.
It may feel strange to carry a machine in your chest. But learning how your device normally works — and how to care for it — helps you spot problems early and get the most out of it.
Want to keep your heart in its best shape? Explore our complete heart health guide and our overview of heart disease, and bring your questions to your next cardiology visit.
Frequently asked questions
What is the difference between a pacemaker and an ICD?
A pacemaker sends small electric signals to keep a slow or irregular heartbeat steady. An ICD watches for a dangerously fast rhythm and sends a shock to reset it, protecting you from sudden cardiac death.
How long does a cardiac device battery last?
A cardiac device battery can last from 6 to 15 years, depending on the device.
Can I have an MRI if I have a pacemaker or ICD?
Most people with a cardiac device can have an MRI. Your doctor and the imaging team must confirm it is safe and take special steps before the scan.
Will my phone or microwave affect my cardiac device?
No. Cell phones, microwaves and security scanners generally do not cause problems for people with cardiac devices.
How soon does a cardiac device start working?
A cardiac device starts working as soon as your doctor finishes setting it up. Its settings may be fine-tuned before or after you leave the hospital.
How often do I need a device check?
You need a device check at least once a year, with more frequent visits at first. Many devices can also send data to your care team by phone or internet.
Is a cardiac device permanent?
Not always. A pacemaker or ICD is usually long term, while a VAD may be used short term — for example, while you wait for a heart transplant.
What should I do if my ICD gives me a shock?
Contact your care team after a shock. Call 911 if you get more than one shock in a short time or a shock with chest pain, trouble breathing or fainting.
What is a leadless pacemaker?
A leadless pacemaker is a tiny pacemaker with no wire. It is placed directly inside the right lower chamber of the heart.
What is a ventricular assist device?
A ventricular assist device (VAD) is a pump that helps a weak heart move blood to the body. It most often supports the left side of the heart.
Related Reading
Permanent Pacemakers: A Complete Guide to Heart Rhythm Management explains how pacemakers treat slow heart rhythms and life with one.
Understanding Implantable Cardioverter Defibrillators (ICD) explains how an ICD detects and shocks dangerous heart rhythms.
Cardiac Resynchronization Therapy (CRT): Procedure and Results explains how CRT helps both heart chambers pump together.
Left Ventricular Assist Device (LVAD): How It Works, Benefits, Risks and Recovery covers how an LVAD pump supports a weak heart.
References
Cleveland Clinic. Cardiac Devices: Types & How They Work. Cleveland Clinic. Last updated December 18, 2024. https://my.clevelandclinic.org/health/treatments/cardiac-devices
Al-Khatib SM. Cardiac Implantable Electronic Devices. N Engl J Med. 2024;390(5):442-454. PMID: 38294976. https://doi.org/10.1056/NEJMra2308353
Bardy GH, Lee KL, Mark DB, et al. Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med. 2005;352(3):225-237. PMID: 15659722. https://doi.org/10.1056/NEJMoa043399
Rose EA, Gelijns AC, Moskowitz AJ, et al. Long-term use of a left ventricular assist device for end-stage heart failure. N Engl J Med. 2001;345(20):1435-1443. PMID: 11794191. https://doi.org/10.1056/NEJMoa012175
Nazarian S, Hansford R, Rahsepar AA, et al. Safety of Magnetic Resonance Imaging in Patients with Cardiac Devices. N Engl J Med. 2017;377(26):2555-2564. PMID: 29281579. https://doi.org/10.1056/NEJMoa1604267
Medical disclaimer
This article is for general education only and is not a substitute for professional medical advice, diagnosis or treatment. Always talk with your doctor about your own heart condition and device.
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