Implanted Rhythm Support
Pacemaker
A pacemaker is an implanted cardiac device that can deliver small electrical impulses when the heart’s natural rhythm is too slow or its conduction is impaired. It is used in selected patients after assessment.
On this page
Understanding the device
What Is a Pacemaker?
A pacemaker is a small battery-powered device placed under the skin, usually near the collarbone. It contains a pulse generator, which senses the heart’s own rhythm and can send small electrical impulses to the heart when they are needed.
The device does not take over the heart. It supports the rhythm when the heart’s natural system is too slow or delayed.
Clinical context
Why Pacing May Be Needed
Pacing is considered in selected situations where a slow or interrupted rhythm is causing symptoms or carries risk. A slow heart rate alone does not mean a pacemaker is needed.
Symptomatic slow rhythm
When a slow rhythm is the likely cause of symptoms such as fainting or marked tiredness.
Sinus node dysfunction
When the natural pacemaker does not fire or respond as it should.
Certain AV conduction disorders
When the signal between the upper and lower chambers is delayed or blocked.
Individual decision
The decision depends on the symptoms, the rhythm findings and the overall situation.
The principle
How a Pacemaker Works
Most pacemakers follow the same basic cycle, although devices differ in how they are designed and programmed.
Sense
The device senses the heart’s own electrical activity.
Assess
It checks whether a beat has occurred when expected.
Pace
If a beat is missing, it sends a small impulse to the heart.
Record
Events are stored for review at device checks.
Different devices can pace one or both sides of the heart. The type is chosen according to the rhythm problem.
The system
Pacemaker Components
A pacemaker system has a few main parts. The exact design differs between devices, so only general features are described here.
Pulse generator
Contains the battery and the electronics that sense and pace.
Leads
Thin insulated wires that carry signals between the heart and the generator. Some systems have no leads.
Electrodes
Contact points at the lead tip that touch the heart muscle.
Programming
Settings are adjusted by the care team using a programmer.
A rate problem
Sinus Node Dysfunction
When the natural pacemaker fires too slowly, pauses, or fails to speed up with activity, a pacemaker may be considered in selected patients. More detail on causes, symptoms and assessment is on the bradycardia page.
A conduction problem
AV Block
In AV block, the electrical signal is delayed or interrupted on its way from the upper to the lower chambers. Blocks range from mild delays to complete interruption of the signal.
Whether pacing is advised depends on the type of block, the symptoms and the findings of tests. Mild forms may only need follow-up.
Device types
Types of Pacing System
Single-chamber
Paces one chamber, usually the right ventricle and sometimes the right atrium. It is used when pacing one chamber is enough for the rhythm problem.
Dual-chamber
Has leads in the right atrium and right ventricle so that the upper and lower chambers can work in sequence. It is often considered when conduction between the chambers is affected.
Leadless pacemaker
A small capsule placed inside the heart through a vein in the groin, with no lead and no pocket under the skin. It suits selected patients and rhythm problems, and the choice depends on the type of pacing needed, anatomy and other factors.
Resynchronisation (CRT)
In some people with heart failure and delayed electrical activation between the sides of the heart, a device that paces both lower chambers helps them contract together. This is a heart-failure treatment decided with the heart-failure team.
One type is not better than another in every case. Your team chooses the system according to the rhythm problem, the heart and your circumstances, and explains the reasons.
The procedure
Implantation Overview
The details vary with the type of device and the patient. The steps below are a general outline.
Assessment
Review of the rhythm, symptoms and tests.
Preparation
Discussion of the procedure, its risks and the type of device.
Anaesthesia
Usually local anaesthetic, often with sedation.
Access
A small cut is made near the collarbone and a vein is used to reach the heart, for devices with leads.
Lead placement
Leads are guided to the heart and tested.
Device placement
The generator is placed in a small pocket under the skin.
Recovery
Monitoring after the procedure before going home.
Recovery
After Implantation
Instructions for caring for the wound and for activity are given to each patient and depend on the device and the person. The arm on the side of the device may need to be used gently at first.
Contact your care team if the wound is red, swollen or painful, or if you have a fever. Follow-up visits are arranged before you leave.
Ongoing care
Device Checks
A pacemaker is checked regularly, in clinic or by remote monitoring where available. The check reads information stored in the device and may adjust its settings.
Battery
The remaining battery life is checked. The generator is replaced when the battery nears the end of its life.
Leads
Lead function is tested at each check.
Recorded events
The team reviews events stored by the device.
Settings
Programming is adjusted when needed.
Living with a device
Everyday Life
Most people return to normal daily activity after recovery. Your care team will give advice that fits your device and your situation.
Follow medical instructions
Attend device checks and report new symptoms.
Carry identification
Keep your device card with you, especially when travelling.
Tell your care providers
Let doctors, dentists and others know you have a device before procedures or scans.
Equipment and procedures
Your team will explain whether any equipment or tests need precautions.
Comparison
Pacemaker vs ICD
Both are implanted devices, but they are not interchangeable. They have different main purposes.
Pacemaker
Supports slow rhythms
Mainly supports slow or conduction-related rhythms by pacing when needed.
Does not treat dangerous fast ventricular rhythms.
ICD
Treats dangerous fast rhythms
Monitors the rhythm and can treat selected dangerous ventricular arrhythmias with pacing or a shock. Some ICDs can also pace, depending on the device.
Used in selected patients after assessment.
Questions