Overview of Pacemaker Insertion
Pacemakers are devices that help control the heartbeat. They work by creating electrical signals strong enough to trigger a heartbeat. This can range from very brief signals (0.5 milliseconds) to longer ones (25 milliseconds) and can be as little as 0.1 volt or as much as 15 volts. The signals can be sent up to 300 times a minute. Your doctor or a pacemaker technician will be able to adjust the rate of the beat, the duration of each electrical pulse, and the strength. Pacemakers can either be temporary or permanent. Temporary pacemakers are usually used to temporarily stabilize the heart or to help during a surgical procedure. Permanent pacemakers, usually implanted inside the body, are more complex.
The idea of using electricity to control the heart dates back to the late 1700s, when Luigi Galvani found that he could make a frog’s heart contract just by passing an electric current through it. The idea became more real around 100 years later when Guilliame de Boulogne used electricity to bring a child back to life after drowning. His method involved applying an electrical current to the child’s chest while also connecting the child’s leg to a different electrode. This led to the term “artificial cardiac pacemaker” being used for the first time in 1932.
Pacemakers are one type of cardiac implantable electronic device (CIED). Other examples of CIEDs include implantable cardioverter-defibrillators (ICDs), which were introduced in the 1950s and designed to restart the heart if it stops. The term CIED is also used for the wires (insulated with non-insulated tips) that lead to these devices, which are either inserted through a vein or put in place by a heart surgeon.
Pacemakers are made up of two main parts: the pulse generator and the leads or electrodes.
To classify pacemakers, a code was developed by two medical societies to describe device characteristics. This code was last revised in 2002 and uses five letters to represent different functions of the pacemaker. For example, the first letter indicates which chamber of the heart is paced by the device, and the last two letters, which are less commonly used, indicate additional pacing capabilities.
Pacemakers have evolved significantly over time. Even the simplest versions today have capabilities such as AAI and VVI modes. In AAI mode, the pacemaker paces and senses in the heart’s top chambers and each detected heartbeat triggers the generator to fire. In VVI mode, the pacemaker paces and senses the heart’s lower chambers and is suppressed by any detected heartbeats from the ventricles, the lower chambers of the heart.
Anatomy and Physiology of Pacemaker Insertion
The cardiac conduction system is a group of specialized heart cells. These cells create and send out electrical signals that control the heart muscles. These signals help the heart pump blood smoothly and efficiently throughout the body.
Here are some of the main parts of the cardiac conduction system:
The sinoatrial (SA) node: This part acts like the heart’s natural pacemaker. It creates electrical signals that travel through the upper chambers of the heart, called the atria, and then to the lower chambers, called the ventricles. The SA node is a structure filled with special cells and is located near the upper right chamber of the heart. It is usually supplied with blood from branches of the right coronary artery or from the left circumflex artery – a major blood vessel in the heart. However, in some cases, blood can come from both of these sources.
The atrioventricular (AV) node: This node takes the electrical signals from the atria to the ventricles, ensuring that the heart contracts smoothly and efficiently. You can find the AV node in the wall that separates the two atria. Most of the time, the AV node gets blood from branches of the right coronary artery. In some people, however, it might be supplied by the left circumflex artery.
The Bundle of His: This part helps to connect the lower part of the AV node to the rest of the electrical system in the heart. It’s located in a central part of the heart and continues its way to another part, called the interventricular septum, where it divides into smaller branches.
Bundle branches and Purkinje fibers: The bundle branches start at the top of a muscular wall inside the heart and continue to the tip of the right lower chamber. The left bundle branch varies in its structure; sometimes, it divides into an anterior and posterior part while in others, it gives out a separate component. The bundle branches end in the Purkinje fibers, a set of fast-working fibers in the inner surface of the heart’s muscles. These fibers send electrical signals to both lower chambers of the heart at the same time, so they contract together.
Why do People Need Pacemaker Insertion
Permanent pacemakers are devices placed in the body to regulate a slow heart rate, or, as its known medically, bradycardia. This can happen because of an issue with the heart’s natural pacemaker (the sinus node), or a block in the electrical signals from the upper to lower chambers of the heart (atrioventricular block). Doctors use pacemakers in the following situations:
– When the sinus node isn’t working right: People often need a pacemaker if they have problems with this natural pacemaker of the heart. These problems, collectively known as sinus node dysfunction, could include a slow heart rate that’s causing symptoms, a heart rate that doesn’t increase with activity when it should, long pauses between heart beats or changing heart rate patterns with episodes of very fast and very slow heart rates.
– Blockage in the heart’s electrical signals (atrioventricular block): Doctors recommend pacemakers for anyone with an advanced type of this blockage, like Mobitz II, and for those with a complete block. This is the case even if they aren’t having symptoms and even if there’s no clear underlying cause for the blockage.
– People with certain muscle disorders: Some muscle disorders can affect the heart’s electrical system, causing blockages. If you have a neuromuscular disorder and either a second-degree block (a type of partial blockage), a high-grade block (more serious partial blockage), a complete block, or a disease affecting the lower part of the heart’s electrical system (which can usually be determined by an HV interval longer than 70 milliseconds), your doctor might say you need a pacemaker, regardless of whether you have symptoms.
– Certain types of slow heart rate: If you have a type of irregular heartbeat known as atrial fibrillation and a slow heart rate as a result, your doctor might recommend a pacemaker even if you haven’t noticed any symptoms.
– Side effect of necessary medicines: Sometimes, medicines you need to take for other heart problems can cause your heart rate to slow down. If this happens and there are no alternative medicines to take, your doctor could suggest getting a pacemaker.
– Significant form of first-degree blockage (atrioventricular block) or atrioventricular Wenckebach: Your doctor might consider a pacemaker if you have symptoms from a specific kind of first-degree block (where the electrical signals are just slowed down, not blocked), typically determined by a PR interval (the time from the start of the electrical signal to when the lower chambers contract) of more than 300 milliseconds. The same is true for a kind of blockage known as Wenckebach, which is less serious but could still cause noticeable symptoms.
– A specific type of complete blockage with certain symptoms: If you have a form of complete blockage known as bifascicular block and have experienced fainting or feel as if you’re about to faint without any other identifiable cause, your doctor might consider a pacemaker for you.
When a Person Should Avoid Pacemaker Insertion
While there are no hard and fast rules that say a pacemaker cannot be implanted, it’s generally not recommended to do this when a patient has an active infection, particularly if bacteria are present in the bloodstream. Other reasons why a pacemaker might not be fitted include the patient not wanting the procedure or if the patient is very ill and the pacemaker isn’t expected to make their life better. If a person’s heart and blood vessels aren’t suitable for the usual method of putting a pacemaker in through a vein, a different approach may be used. This involves placing the lead of the pacemaker on the outer layer of the heart using thoracoscopy or thoracotomy – procedures to open up the chest and get a better look at the heart.
Equipment used for Pacemaker Insertion
Putting in a pacemaker is a specific kind of medical procedure that needs certain equipment to make sure everything goes smoothly, safely, and successfully. Here are the main tools and equipment needed:
- Pacemaker pulse generator: This device powers the pacemaker and sends electric signals to the heart through special wires called ‘leads’.
- Pacemaker leads: These are insulated wires that transport the electric signals from the pacemaker to the heart. Different types of leads are used depending on what the patient needs, including those aimed at the upper and lower chambers of the heart.
- Implantation tools:
- Scalpel and dissection instruments: These are used to make the cut for surgery, separate tissues to get to where the pacemaker will be implanted, and create a small area where the pacemaker will be placed.
- Forceps and scissors: They’re used to handle tissues and cut threads used for stitching.
- Needles and threads: For stitching the leads and cut area after the pacemaker is put in place.
- Fluoroscopy equipment: This equipment provides live x-ray images of the heart and where the leads are placed during the procedure to make sure everything is positioned correctly.
- Electrocautery: A tool used to stop bleeding during the surgery by sealing the tissue and blood vessels.
- Sterile drapes, surgical gowns, and gloves: These ensure the surgery area stays clean and lowers the risk of infection during the procedure.
- Cardiac monitoring equipment: This keeps a constant eye on the patient’s heart rhythm and vital signs during the procedure.
- Anesthesia equipment: Anesthesia is used to make the patient comfortable during the implantation.
- X-ray machine: It works with fluoroscopy to provide a clear view of the heart and help guide where the leads should be placed.
- Temporary pacemaker: This is kept handy in case of complications or if temporary pacing is needed during or right after the procedure.
- ECG machine: This keeps track of the patient’s heart rhythm and makes sure the pacemaker is working correctly after it’s been implanted.
- Surgical lights: These provide good lighting during the procedure.
- After-surgery monitoring equipment: This checks on the patient as they gradually wake up from the procedure.
The operating room also has other standard surgical tools and supplies, like sterile cotton pads, sponges, and liquids for cleaning the wound. Inserting a pacemaker is usually done in a specific room designed for heart-related procedures or a special operating room furnished with all the necessary equipment to ensure the procedure goes well and the patient is safe.
Who is needed to perform Pacemaker Insertion?
Placing a pacemaker in a patient is done by a certain kind of heart doctor known as a cardiac electrophysiologist or a heart surgeon. This operation needs a team of people who are very experienced and trained in looking after patients with these complex needs. Others who might be part of this team could include an electrophysiology fellow (which is like a doctor in training), a nurse who specializes in electrophysiology, a technician, a doctor or assistant who provides anesthesia (medicine to make you sleep and not feel pain), and a person who takes X-ray pictures.
Preparing for Pacemaker Insertion
Before having a pacemaker implanted, your doctor will thoroughly check your health, see if this procedure is right for you and weigh any risks against the benefits it could offer. Your doctor will also make sure you do not have an infection, and you might be given antibiotics for protection (like cephazolin or flucloxacillin, or vancomycin if you’re allergic), a bit before the procedure.
For those taking medicine to prevent blood clotting (anticoagulants), there are extra precautions because these drugs can cause bleeding during the procedure. For some people, with a lower risk of stroke, these medications can be stopped temporarily. However, in cases where stopping might be dangerous, like in patients with mechanical hearts or at a high risk of stroke, the procedure can proceed with no interruption in the medication, as long as it is not going to increase the risk of causing a bleeding problem during the surgery.
A study named BRUISE-CONTROL 2 showed no change in bleeding problems in patients who continued taking these medications during their pacemaker implants. However, the decision to stop or continue the medication should be made on an individual basis, considering the patient’s specific situation and their risk of bleeding and stroke.
Before the procedure, the doctors will make sure to have all the necessary equipment ready and perform safety checks. There will also be a team ready to help with anesthesia and deal with any emergencies that might arise. This is done to ensure your safety and comfort during the procedure.
How is Pacemaker Insertion performed
If you’re getting an implant, the left side is usually the better side to have it inserted because lead placement is more straightforward and comfortable for most people. But, we will decide which side is the best fit for you. Then, we numb the area with a local anesthetic. After that, we make a small cut under your collarbone. To put the implant in the right place and prevent it from moving, we create a small “pocket” in the area under the skin.
Next, we need to get access to your blood vessels. This is done either by inserting a needle into a vein under your collarbone or by making a small cut in a vein near the curve of your shoulder. Either method is safe, but sometimes we have to do a small, painless X-ray to see your veins better.
To connect the implant with your heart, we use special wires called “leads”. There are two types of leads, active and passive. Active leads hang onto your heart tissue better, so they’re less likely to detach on their own. Usually, we insert the lead into the bottom area of the right heart chamber first, to provide backup if needed. The second lead is placed in the top-right chamber of the heart. We use an X-ray screen to watch where we’re placing the leads.
Once the leads are in the right place, we attach them to your heart tissue. Then, we check if the leads are working well and sending the right signals. We also verify that they’re stable and not moving. Usually, this is a straightforward process, but sometimes we need to make small adjustments.
Lastly, we attach the leads to the implant and place it in the “pocket” we created earlier. The implant should be easy to reach and be in a position that protects the leads. Then, we stitch up the pocket and clean it to prevent infections. Closing up the pocket may differ from person to person, but it’s usually done in two stages. The area under the skin is stitched up first, then the skin is stitched up.
After the procedure, we’ll be keeping a close eye on your heart rate, blood pressure, and oxygen levels. We will also check the implant site for any signs of infection like redness or swelling. While getting back to your regular activities should be okay, you should avoid heavy lifting or strain with the arm where the implant was inserted.
During your follow-up visits, our main objective will be to ensure you’re healing well, avoid any complications and to make sure the implant is functioning properly. The visits will also be an opportunity for us to educate you on taking care of yourself after the procedure and help you with any problems or questions.
Possible Complications of Pacemaker Insertion
Implanting a pacemaker is usually a safe procedure with a high success rate. However, like all surgeries, it can have some risks and complications. These complications can vary from minor to severe.
Here are some of the common problems:
– Arrhythmia: This is a term for when your heartbeat is irregular. It’s usually temporary and can occur during the surgery while the pacemaker lead is being placed, particularly when it’s moved through the heart valves into the right ventricle. However, this is rare.
– Infection: Sometimes, an infection might happen at the site of the surgery or where the pacemaker leads enter the heart. Signs of an infection can be swelling, redness, pain, and a fever. In severe cases, the whole pacemaker device might have to be removed, and antibiotics could be necessary. Between 0.6% and 3.4% of pacemaker insertions will result in an infection.
– Bleeding and pocket hematoma: This is when you bleed during or after the procedure. Usually, it’s not serious. But, if there’s heavy bleeding, it can cause a pocket hematoma, which is when blood collects under the skin. If this happens, additional surgery might be needed to remove it. The chances of getting a pocket hematoma can range from less than 0.5% to 16%, and it can increase the risk of an infection.
– Lead-related complications:
* Lead dislodgement: This is when the wires that connect the pacemaker to your heart move from where they’re supposed to be. This might mean that your heart isn’t being paced correctly.
* Lead fracture: If a wire connecting the pacemaker to your heart breaks, your pacemaker might stop working properly.
* Venous thrombosis: This is a blood clot in the vein where the wires are placed. It might block blood flow.
* Pneumothorax: During the procedure, a lung might accidentally be punctured. This can cause air to collect in the chest cavity, which might need to be drained.
* Cardiac perforation: In rare cases, the pacemaker wires can accidentally puncture a part of the heart. It’s uncertain how often this might happen, but estimates range from less than 0.1% to 1.5% of procedures.
Other complications can include:
– Allergic reaction: Some people might be allergic to materials used in the pacemaker like the metal alloys or medications.
– Device-related complications:
* Battery depletion: The pacemaker battery usually lasts about 10 years before needing to be replaced.
* Device malfunction: The pacemaker might not work correctly and could have to be replaced or reprogrammed.
* Psychological impact: Having a pacemaker implanted can sometimes cause anxiety, depression, or difficulty adjusting.
– Long-term complications: Over time, there is a small risk of complications such as lead insulation breakage, lead calcification, or infection of the device pocket.
While the overall risk of having complications is quite low, many patients experience a significant improvement in their quality of life with a properly functioning pacemaker. Doctors take care to assess the risk for each patient and monitor them closely before, during, and after the surgery to minimize the likelihood of these complications.
What Else Should I Know About Pacemaker Insertion?
Pacemakers are key in treating certain heart conditions because they control the heart’s rhythm. Here’s how they play a significant role in our health:
* Treating Slow Heartbeat
* The main job of pacemakers is to help with bradycardia, a condition where the heart is beating too slowly. Slow heartbeats can make you feel dizzy, tired, or short of breath. Pacemakers ensure your heart keeps a steady pace and stop these symptoms from happening.
* Managing Heart Block
* A heart block happens when the heart’s electrical signals, which govern the heartbeat, are slowed down or blocked. A pacemaker is able to cope with these blockages by sending electrical signals directly to the important parts of the heart or by making sure the heart’s chambers contract in time with each other.
* Improving Quality of Life
* If you have a slow heartbeat or a heart block and show symptoms, pacemakers can do wonders for your health and lifestyle. They lower symptoms like fatigue, fainting and not being able to catch your breath. Thanks to pacemakers, you can live a normal life and do physical activities without any limitations your heart condition may impose.
* Preventing fainting and heart attacks
* Pacemakers can prevent severe circumstances linked to extremely slow heartbeats, such as fainting or even sudden heart attacks in certain cases. They ensure a constant heart rate and lower the odds of dangerous irregular heartbeats.
* Personalisation
* Pacemakers can be personalised and changed to suit each patient’s needs, like varying heart rate settings for when you’re resting or exercising.
Many pacemakers today include features like algorithms that increase your heart rate when you’re exercising.
* Advances in Technology
* Developments in pacemaker technology have made the devices last longer, decreased complications and allowed for improved monitoring through remote systems. This progress results in better patient care and outcomes for people who need pacemakers.
* More than Just Bradycardia
* Besides slow heartbeat, pacemakers can sometimes be used for certain types of heart failure or to manage specific irregular heartbeats that are not responsive to other treatments. They can help boost heart function and overall heart health in chosen patient groups.
In short, pacemakers are a crucial treatment for patients with a range of heart rhythm disorders. They provide great benefits by controlling the heart rate and rhythm, decreasing symptoms, and lessening the risk of critical complications linked with slow heartbeats and heart blocks.
