A pacemaker is a small electronic device implanted in your chest that sends electrical pulses to your heart to keep it beating at a steady rhythm. It’s most commonly used when the heart beats too slowly, a condition called bradycardia, typically when the resting heart rate drops below 40 beats per minute. About the size of a large coin, the device sits just under the skin near your collarbone and connects to your heart through thin, flexible wires.
Why Someone Needs a Pacemaker
The heart has its own natural electrical system that tells it when to beat. When that system malfunctions, the heart can beat too slowly, pause for too long, or lose coordination between its upper and lower chambers. A pacemaker steps in to fill those gaps.
The two most common reasons for getting a pacemaker are sinus node dysfunction and heart block. Sinus node dysfunction means the heart’s natural “spark plug,” a cluster of cells in the upper right chamber, isn’t firing properly. Heart block means the electrical signal gets delayed or stopped as it travels from the upper chambers to the lower chambers. In both cases, the result is a heart that doesn’t pump blood fast enough to meet your body’s needs, which can cause dizziness, fainting, fatigue, or shortness of breath.
Pacemakers are also used for people who faint due to an overly sensitive nerve reflex in the neck (carotid sinus syndrome), for certain cases of heart failure where the chambers beat out of sync, and occasionally after heart surgery or a heart transplant when the heart’s electrical system needs backup support. In infants born with a complete heart block, a pacemaker may be needed if the heart rate falls below 55 beats per minute.
What’s Inside the Device
A pacemaker has two main parts: the pulse generator and the leads. The pulse generator is a small sealed metal case, roughly the size of a silver dollar, that contains the battery, a tiny computer chip, and an antenna for wireless communication. The case itself doubles as a conductor for the electrical circuit. Inside, a lithium-iodine battery provides steady, long-lasting power.
The leads are thin insulated wires that run from the pulse generator through a vein and into specific chambers of your heart. At the tip of each lead, small electrodes touch the heart muscle. These electrodes do two jobs: they sense your heart’s natural electrical activity, and they deliver a tiny electrical pulse when the heart needs a nudge. The computer chip continuously monitors your heartbeat and only sends a pulse when one is needed, so the device stays quiet when your heart is beating normally on its own.
Types of Pacemakers
The type of pacemaker you receive depends on which part of the heart’s electrical system is malfunctioning and how many chambers need pacing.
- Single-chamber pacemaker: One lead connects to either the right upper or right lower chamber of the heart. Most often it’s placed in the lower chamber (ventricle) to maintain a steady pumping rhythm.
- Dual-chamber pacemaker: Two leads connect to both the right upper and right lower chambers. This allows the device to coordinate the timing between both chambers so they contract in proper sequence, keeping blood flowing smoothly from upper to lower.
- Biventricular pacemaker: Three leads connect to the right upper chamber and both lower chambers. This type is designed for people with heart failure whose lower chambers have fallen out of sync. By making both sides of the heart pump together, the heart works more efficiently. This is sometimes called cardiac resynchronization therapy.
Leadless Pacemakers
A newer option is the leadless pacemaker, a tiny capsule about the size of a large vitamin that sits entirely inside the heart. Instead of being surgically placed under the skin with wires threaded through veins, a leadless device is delivered through a catheter inserted in the leg and anchored directly in the heart’s lower chamber. There’s no chest incision, no visible bump under the skin, and no leads that can shift or break over time.
Studies show that people with leadless pacemakers report fewer activity limitations, less surgical discomfort, and less emotional distress compared to those with traditional devices. However, leadless pacemakers currently work best for patients who only need single-chamber pacing. People who require pacing in the upper chamber, or whose heart anatomy includes an unusually enlarged upper chamber, typically still need a conventional pacemaker with leads.
What the Procedure Is Like
Pacemaker implantation is a relatively minor surgical procedure that usually takes one to two hours. You’re given local anesthesia and often a mild sedative, so you’re awake but relaxed. The surgeon makes a small incision near your collarbone, threads the leads through a vein into the heart, and positions them using X-ray guidance. The pulse generator is then connected to the leads and placed in a small pocket just under the skin.
Recovery is quick. Most people stay in the hospital for a few hours to overnight. You can return to daily activities within a few days, though you’ll typically be asked to avoid driving and heavy lifting for at least a week. For the first several weeks, your doctor will likely recommend not raising your arms above your head or doing intense physical activity, since this could shift the leads before they’ve had time to settle into place.
Potential Complications
Like any procedure, pacemaker implantation carries some risk. The most common issue is lead displacement, where a wire shifts out of its intended position. This happens in roughly 6 to 8 percent of cases and usually requires a follow-up procedure to reposition the lead. Bruising at the incision site is also common, particularly in people taking blood-thinning medications. Infection at the device pocket is less frequent but is the complication doctors watch most carefully, since a device-related infection can require the entire system to be removed and replaced.
Replacing a pacemaker when the battery runs out carries a somewhat higher complication risk than the original implantation, particularly for infection and skin breakdown over the device pocket. This is one reason doctors monitor battery status closely over the life of the device.
How Long a Pacemaker Lasts
Modern pacemaker batteries last between 5 and 12 years, depending on the type. Single-chamber devices tend to last longer (7 to 12 years) because they use less energy, while dual-chamber models typically last 5 to 10 years. When the battery starts running low, your doctor will schedule a generator replacement. This is a shorter, simpler procedure than the original implant: the surgeon opens the pocket, disconnects the old generator, connects a new one to the existing leads, and closes the incision. The leads themselves usually don’t need to be replaced.
Living with a Pacemaker
Most people with pacemakers live completely normal, active lives. The device works automatically, and you won’t feel it firing in most situations. There are a few practical things to keep in mind, though, mostly related to magnets and electronics.
Strong magnets can temporarily switch a pacemaker into a safety mode that changes how it operates. The FDA recommends keeping cell phones, smart watches, and other consumer electronics at least six inches (15 centimeters) away from the device. In practical terms, this means don’t rest your phone on your chest or carry it in a breast pocket on the same side as your pacemaker. At that distance, interference is extremely unlikely. Metal detectors and airport security scanners are generally safe to walk through quickly, but you should carry your pacemaker ID card when traveling.
MRI scans were once off-limits for pacemaker patients, but many modern devices are designed to be MRI-compatible. Your doctor can confirm whether your specific model is cleared for MRI and what settings need to be adjusted before the scan.
Ongoing Monitoring
After implantation, your pacemaker needs regular check-ups to make sure it’s functioning properly and to track battery life. The current recommendation is to have the device checked every 3 months, either through an in-person clinic visit or through remote monitoring.
Remote monitoring has become the standard for most pacemaker patients. A small home monitor, placed on your nightstand or nearby, wirelessly receives data from your pacemaker and transmits it to your medical team. Some systems send daily transmissions automatically, while others are programmed to send data on a set schedule or when the device detects something unusual. This means your doctor can often catch issues, like a lead problem or a change in your heart rhythm, before you ever notice symptoms. In-person visits are still needed periodically, but remote monitoring has made the process far less burdensome for most people.