A pacemaker is a small electronic device implanted in your chest that keeps your heart beating at a normal rate. It monitors your heart’s rhythm continuously and sends tiny electrical pulses to correct the beat when it detects a problem, like a heartbeat that’s too slow or irregular. Most people with pacemakers live fully active lives, and the devices typically last 5 to 12 years before the battery needs replacing.
How a Pacemaker Works
Your heart has its own natural electrical system that tells it when to beat. Sometimes that system malfunctions, causing the heart to beat too slowly, skip beats, or fall out of rhythm. A pacemaker steps in only when it senses trouble. If your heart is beating normally, the device stays quiet. The moment it detects an irregular or sluggish beat, it fires a small electrical signal to get your heart back on track.
Modern pacemakers are also “rate-responsive,” meaning they automatically speed up your heartbeat during physical activity and slow it back down at rest. This lets your heart respond naturally to exercise, climbing stairs, or any exertion, much the way a healthy heart would.
Parts of the Device
A traditional pacemaker has three main components. The pulse generator is a small metal box, roughly the size of a matchbook, that contains a battery and the electronic circuitry that creates electrical pulses. Thin, flexible wires called leads run from the generator through a vein and into one or more chambers of the heart. At the tip of each lead are electrodes that both sense your heart’s natural rhythm and deliver corrective pulses when needed.
Newer leadless pacemakers skip the wires entirely. The entire device, about the size of a large pill capsule, is placed directly inside a heart chamber through a small tube threaded up from a vein in the leg. Because there are no external wires, leadless models carry a lower risk of certain complications like lead-related infections or fractures. They’re not suitable for every patient, but their use is growing.
Why Someone Might Need One
The two most common reasons for pacemaker implantation are sinus node dysfunction and heart block.
Sinus node dysfunction means the heart’s natural pacemaker (a cluster of cells in the upper right chamber) isn’t firing properly. This can cause an abnormally slow heart rate, long pauses between beats, or a heart that can’t speed up appropriately during activity. Symptoms often include fatigue, dizziness, fainting, and shortness of breath. A pacemaker is typically recommended when these symptoms clearly link to a documented slow heart rate, or when the resting heart rate drops below 40 beats per minute.
Heart block occurs when electrical signals between the upper and lower chambers of the heart are delayed or completely interrupted. It’s graded by severity. In first-degree block, signals are slow but still get through. In second-degree block, some signals are dropped entirely, causing skipped beats. In third-degree (complete) block, no signals reach the lower chambers at all, and the heart relies on a much slower backup rhythm. Complete heart block almost always requires a pacemaker, regardless of whether you feel symptoms.
Less commonly, pacemakers are implanted for conditions like alternating bundle-branch block (where the electrical pathways in the lower heart take turns failing) or heart rhythm problems that develop during exercise.
The Implantation Procedure
Pacemaker surgery is considered minor. For a traditional device, a surgeon makes a small incision just below the collarbone, threads the leads through a vein into the heart, and tucks the pulse generator into a small pocket created under the skin. You’re typically awake but sedated, and the procedure takes one to two hours. Most people stay in the hospital overnight for monitoring and go home the next day.
For a leadless pacemaker, there’s no chest incision. The device enters through a catheter in the leg and is anchored directly in the heart. Recovery from this approach tends to be faster since there’s no surgical pocket to heal.
Recovery and Returning to Normal Life
In the first few weeks after implantation, you’ll need to limit movement of the arm on the side where the device was placed. This gives the leads time to settle securely into position. Lifting heavy objects, raising that arm above your shoulder, and vigorous activity are generally off-limits for four to six weeks.
After that initial healing period, most people return to their normal routines, including exercise, driving, and work. You’ll have a follow-up appointment to check the device settings and make adjustments. From there, pacemaker checkups happen once or twice a year, and many modern devices can transmit data to your doctor remotely, reducing the need for in-person visits.
Battery Life and Replacement
Pacemaker batteries aren’t rechargeable, so the device eventually needs replacing. Single-chamber pacemakers (with one lead) typically last 7 to 12 years. Dual-chamber models, which pace both the upper and lower heart, draw more power and last closer to 5 to 10 years. How often the pacemaker fires, the energy level of each pulse, and your individual heart rhythm all affect how quickly the battery drains.
When the battery runs low, the pulse generator is swapped out in a relatively simple procedure. The original leads usually stay in place if they’re still functioning well, so the replacement surgery is quicker and less involved than the first implant.
Risks and Complications
Pacemaker implantation is one of the most commonly performed cardiac procedures, and serious complications are uncommon. Large-scale data puts the overall complication rate at roughly 2 to 3.4%. The most significant risks include infection at the implant site, a lead shifting out of position, bleeding or bruising around the pocket, and, very rarely, a puncture of the heart wall during lead placement. Most of these complications are manageable and caught early through post-operative monitoring.
Living With a Pacemaker
Everyday electronics like smartphones, microwaves, and televisions don’t pose a meaningful risk to modern pacemakers. The general recommendation is to keep your phone on the opposite side of your body from the device and avoid resting it directly over the implant, but casual use is fine.
The bigger interference concerns come from the medical environment. Certain surgical tools (particularly a type called monopolar electrosurgery), MRI machines, radiation therapy equipment, and procedures like radiofrequency ablation or electroconvulsive therapy can all interact with pacemakers. This doesn’t mean these procedures are off-limits. Many newer pacemakers are MRI-compatible, and hospitals have protocols to adjust device settings before and after these treatments. What matters is that every healthcare provider you see knows you have a pacemaker so they can plan accordingly.
Other medical devices that can occasionally interfere include transcutaneous electrical nerve stimulation (TENS) units used for pain relief and lithotripsy machines used to break up kidney stones. In each case, the interaction is manageable with advance planning. You’ll carry a pacemaker ID card with your device details, and wearing a medical alert bracelet is a practical backup.
Strong industrial equipment, like arc welders or large electrical generators, can also cause interference. If your work involves this type of machinery, your cardiologist can advise on safe distances and precautions specific to your device model.