What Are Pacemakers?

Overview

A pacemaker is a medical device that is implanted to help regulate and maintain a steady heartbeat. It is commonly used to treat conditions with abnormal heart rhythms like arrhythmia, where the heart beats too slowly (bradycardia) or irregularly. This compact device is typically placed under the skin near the collarbone. The pacemaker functions by monitoring the heartbeat and, when necessary, emits electrical impulses to prompt the heart to beat at a consistent and healthy rate. Pacemakers can serve as an invaluable solution for people with irregular heartbeats or bradycardia (slow heart rate), by ensuring adequate blood flow and oxygen delivery throughout the body.¹ Pacemakers have been a crucial advancement in medical technology, allowing many people with heart rhythm disorders to lead more normal and active lives. In this article, we will delve into how pacemakers work, the types of pacemakers, the conditions which require a pacemaker implant, and the risks and complications associated with them.

How do pacemakers work?

The sinus node is located in the right atrium, which serves as the heart's natural pacemaker. It is responsible for generating electrical impulses for rhythmic contractions. An orderly heartbeat requires these signals to travel a specific path to reach the ventricles. Malfunctions in the sinus node can lead to irregularities, causing the heart to beat too fast, too slow, or irregularly, often due to blockages or abnormalities in the heart's electrical pathways.

Pacemakers monitor heart rate, detect abnormalities, and, if necessary, generate electrical impulses through implanted leads to restore a normal heartbeat. Traditional pacemakers consist of three parts:

• A pulse generator which has a battery to create the electrical impulse
• Wires (or leads) which carry the pulses to the heart
• Electrodes, which sense the natural heartbeat

Modern pacemakers work on demand according to your body’s needs. If the pacemaker detects a beat is slow or missed, it sends a signal, but if it is working normally it does not send a signal.

Types of pacemakers

The type of pacemaker you need depends on your heart condition. These are the main types of pacemakers:

Single-chamber pacemaker

Single-chamber pacemakers are a type of cardiac pacemaker that involves the placement of one lead (wire) in either the atrium (upper chamber) or the ventricle (lower chamber) of the heart.² 

Dual-chamber pacemaker

Dual-chamber pacemakers are cardiac devices that consist of two leads (wires) implanted in both the atrium (upper chamber) and the ventricle (lower chamber) of the heart.²

Biventricular pacemaker

Biventricular pacemakers are also known as cardiac resynchronization therapy (CRT). These pacemakers are designed to treat certain cases of heart failure and heart rhythm disorders. These pacemakers have three leads (wires) that are implanted in the right atrium, right ventricle, and left ventricle of the heart. 

Leadless pacemaker

Leadless pacemakers are small, wireless devices designed to regulate heart rhythms. They are implanted directly into the heart’s right ventricle via a long, thin tube called a catheter. 

Who needs a pacemaker?

 Pacemakers can be used to treat certain conditions like:

• Arrhythmia (abnormal heartbeat), which can include bradycardia or tachycardia
• Atrial fibrillation (heartbeat is too fast)
• Heart block
• Cardiac arrest

These are some of the symptoms that may indicate a requirement for a pacemaker:

• Chest pain
• Bradycardia (slow heartbeat)
• Tachycardia (fast heartbeat)
• Irregular heartbeat
• Shortness of breath
• Dizziness
• Nausea
• Fainting
• Swelling in legs, ankles and abdomen
• Frequent urination

If you experience any of these symptoms, it's essential to consult with a healthcare professional for a thorough evaluation. It is important to note that the decision to implant a pacemaker is made based on a careful assessment of specific medical conditions and symptoms.

Pacemaker implantation procedure

Multiple examinations are conducted to assess whether a pacemaker is suitable for your condition. These tests may include:

• Electrocardiogram - used to measure the heart’s electrical activity
• Holter monitor - used to find the irregular heartbeat missed by ECG
• Echocardiogram - used to show blood flow and valve function
• Stress or exercise tests - used to evaluate heart response to physical activity 

Depending on the pacemaker suitable for your medical condition, the surgery performed will differ:

Wired transvenous pacemaker

Here is an overview of the implantation procedure of a wired transvenous pacemaker:

Before the surgery

Your doctor will discuss the surgery and check if you are suitable for the operation.

• Some tests, such as blood tests (to measure blood clotting time) and electrocardiogram (ECG) may be performed.
• Your doctor will ask about any allergic reactions or problems you have with medications or anaesthetics (both local and general)³
• You will be asked to fast before the surgery, and your doctor will specify the duration.³ 
• If you have heart valve disease, your doctor might recommend antibiotics before the surgery³
• Inform your doctor about any history of bleeding disorders or use of anticoagulant medications, aspirin, or other drugs affecting blood clotting. These medications will have to be adjusted before the surgery³

Depending on your medical condition, your doctor may advise other specific preparations.

During the surgery

The pacemaker implantation procedure is minimally invasive and is performed under local anaesthesia.

The following steps are performed during surgery:

• Making a small incision at the site once the anaesthetic takes effect.⁴
• Inserting a sheath or introducer into a blood vessel (transvenous access is preferred, commonly through subclavian or cephalic veins) usually beneath the collarbone⁴
• After successful vein access, a subcutaneous pocket is created for the generator⁴
• Inserting the lead wire through the introducer into the blood vessel, advancing it into the heart.³
• Testing the lead wire to verify proper location and functionality³
• Potentially inserting one, two, or three lead wires based on the chosen device³
• Using fluoroscopy (a type of X-ray) for assistance in testing lead locations.⁴
• Placing the pacemaker generator under the skin through the incision just below the collarbone³
• Attach the lead wire to the generator and place the generator on the nondominant side.³
• Examining the sensing and pacing tests to ensure proper pacemaker function.⁴
• Closing the skin incision with absorbable sutures⁴
• Arm immobiliser applied for 12-24 hours.⁴

After the surgery

• After the surgery, you may be transferred to the recovery room.³ 
• Immediately notify your nurse if you experience chest pain, tightness, or any discomfort at the incision site.³
• Once the prescribed period of bed rest is finished, you can get out of bed with assistance. During your initial attempt to stand, the nurse will support you and measure your blood pressure in different positions: lying down, sitting, and standing³ 
• Upon achieving stable blood pressure, pulse, and breathing, and once you are fully alert, you will either return to your hospital room or be discharged home.³

You can typically resume your daily routine within a few days, but your doctor will advise if more time is needed. Avoid lifting or pulling for a few weeks, and limit movement in the arm where the pacemaker was placed per your doctor's guidance.³

Epicardial pacemaker

This surgical procedure is performed under general anaesthesia. Your doctor will make an incision below your ribs or in the armpit to implant the pacemaker. Then the leads are affixed to the heart's surface instead of being positioned inside its chambers. 

Wireless pacemaker

In this procedure, the doctor will insert a thin long tube called a catheter through a vein in your thigh up to the heart and attach it to the wall of your heart.

Risks and complications

Here are some of the risks and complications associated with pacemaker devices or their surgery:

• Blood clots
• Pacemaker infection (pain, swelling or redness at the site of the pacemaker)
• Collapsed lung
• Twiddler’s syndrome (pacemaker generator pulled out from normal position)
• Swelling, bruising or bleeding due to blood thinners
• Blood vessel or nerve damage
• Endocarditis (infection of the inner lining of the heart)⁴
• Systemic infection (infection in the bloodstream)⁴
• Hemothorax (blood collected in the space between the lung and chest)⁴

Living with a pacemaker

Living with a pacemaker can be quite manageable, and many people lead active and fulfilling lives with this medical device. Here are some general considerations for individuals with a pacemaker:

Follow medical advice

Always follow your doctor's advice and recommendations. Attend regular check-ups to ensure the pacemaker is functioning properly. Take medications as prescribed, and inform your healthcare provider of any changes in your health.

Cell phones 

Most modern cell phones are safe to use, but it's recommended to keep them at least six inches away from the pacemaker. Do not keep the phone close to your pocket or ear near the pacemaker.

Medical procedures

Inform all healthcare professionals about your pacemaker before undergoing any medical procedures. These tests can interfere with the functioning of your pacemaker–

• Electrocautery (surgery to stop blood vessels from bleeding) 
• Magnetic resonance imaging (MRI) 
• Microwave diathermy (for physical therapy) 
• Radiation therapy (for cancer) 
• Shock-wave lithotripsy (for kidney stones) 
• Transcutaneous electrical nerve stimulation (TENS) 
• CT and CAT scans

Electromagnetic interference

Certain electronic devices and equipment can interfere with the functioning of a pacemaker due to their strong electromagnetic fields. Here are some devices:

• Anti-theft systems or electronic article surveillance (EAS)
• Metal detectors for security
• Headphones (with magnet)
• Radios
• Magnets
• Power-generating equipment
• Arc welding equipment
• Jumper cables
• Ab stimulators
• Electronic body fat scales
• Gas-powered equipment and gasoline ignition systems
• Portable car battery chargers
• Electric fences
• Medical alert systems

Summary

Pacemakers are medical devices that are used to treat abnormal heart rhythms by emitting electrical signals to maintain a steady heartbeat. The types of pacemakers include single-chamber, dual-chamber, and biventricular pacemakers, which are used according to specific medical issues. Risks and complications may involve infection, lead displacement, or device malfunction. Living with a pacemaker necessitates routine check-ups, lifestyle adjustments, and precautions around electronic devices. Despite potential complications, pacemakers significantly enhance patients' well-being, ensuring cardiac stability and improving overall quality of life. Regular monitoring and following medical advice are essential for optimal outcomes.