Pacemaker

A pacemaker is a device that sends small electrical impulses to the heart muscle to maintain a suitable heart rate or to stimulate the lower chambers of the heart (ventricles).

The primary purpose of a pacemaker is to maintain an adequate heart rate, either because the heart's natural pacemaker is not fast enough, or because there is a block in the heart's electrical conduction system.

The atria (top chamber of the heart) and ventricles (bottom chamber of the heart) work together, alternating contracting and relaxing to pump blood through the heart. The electrical system around the heart makes this possible.

The normal conduction of the heart begins at the sinoatrial (SA) node, located in the right atrium. The electrical activity spreads through the walls of the atria, causing them to contract.

Next, the electrical impulse travels through the AV node, located between the atria and ventricles. The AV node acts like a gate that slows the electrical signal before it enters the ventricles. This delay gives the atria time to contract before the ventricles do.

From the AV node, the electrical impulse travels through the His-Purkinje network, a pathway of specialised electricity-conducting fibres. Then the impulse travels into the muscular walls of the ventricles, causing them to contract. This sequence occurs with every heartbeat (usually 60–100 times per minute).

If the electrical pathway described above is interrupted for any reason, changes in the heart rate and rhythm occur that make a pacemaker necessary. Pacemakers are used to treat brady-arrhythmias, slow heart rhythms that may occur as a result of disease in the heart's conduction system (such as the SA node, AV node or His-Purkinje network).

Are there different types of pacemaker?

The pacemaker consists of two parts: first, a box which houses the electronics (the "device"), and second, one or more wires which connect the box to the heart muscle (the "leads").

The types of pacemakers are listed below. Your doctor will decide what type of pacemaker you need based on your heart condition.

Your doctor also determines the minimum rate (lowest heart rate) to set your pacemaker. When your heart rate drops below the set rate, the pacemaker generates (fires) an impulse that passes through the lead to the heart muscle. This causes the heart muscle to contract, creating a heartbeat.

Leadless pacemaker
A leadless pacemaker is a small, one-piece device that is implanted inside the heart to regulate the heart’s rhythm. The device monitors the heart rate and rhythm and provides electrical stimulation when the heart does not beat or beat too slowly.

Leadless pacemakers are about 3 to 4 centimeters long, with an estimated longevity of 10 years.

Leadless pacemakers are not suitable for everyone. Your doctor will decide the type of pacemaker that you require.

What is a Loop recorder

An Insertable cardiac monitor (ICM) or loop recorder is inserted just under the skin, and it offers continuous monitoring of your heart rhythm and record abnormal rhythm if needed.

Depending on the model, it may last up to 3 years.

Who needs a Loop recorder?

Loop recorder is usually implanted in the following group of patients:

• Patients who experience symptoms such as dizziness, palpitation, syncope that are suggestive of a cardiac arrhythmia
• Patients who undergo holter test/ multiday ECG tests but do not yield any abnormal results 
• Patients who have prior stroke and the physician would like to rule out chances of atrial fibrillation

How to monitor Loop recorder?

Patients implanted with loop recorder will be enrolled for the remote monitoring service. This allows earlier detection of any abnormal cardiac arrhythmia.

If you experience symptoms such as palpitations, giddiness or syncope, you can record down via a ‘clicker’ or home monitoring app. The cardiac physiologist will then co-relate your symptoms with the ECG during that time. Any abnormalities will be reported to your electrophysiologist.

Risks

A device implant is generally a safe procedure. However, as with any invasive procedure, there are risks. Special precautions are taken to decrease your risks.

Your doctor will discuss your risk with you as every individual is different. In general, the risk of implanting a pacemaker is low — only 1% or less of serious complications. These include (but are not limited to) infection of the pacemaker which, if serious, may need removal of the pacemaker altogether; bleeding; pneumothorax ("collapsed lung"); cardiac perforation; and device malfunction.

All of these complications are treatable.

If I decide to have a pacemaker, when will I be admitted for the implantation procedure? How long can I expect to be admitted for?

Your doctor will arrange a date for you to be admitted to the hospital. Usually you are admitted on the day of the procedure; occasionally, you will be admitted the day before. Most patients can expect to be discharged the following day; occasionally, your hospital stay may be longer if the procedure is difficult or complicated.

Do I continue to take my medications till the day of the procedure?

Your doctor should already have instructed you on what to do before the procedure.

Please check with your doctor before discontinuing any medications. The following information is a general guide only.

If you are on warfarin, this will normally need to be discontinued around 5 days prior to the procedure, and a blood test ("INR") taken to confirm that your blood clotting is normal prior to implantation. Please check with your doctor before discontinuing your medications.

If you are taking aspirin or clopidogrel (Plavix), you may be asked to discontinue one or both of these prior to implantation; however, please confirm this with your doctor.

You can normally continue taking your other medications as usual.

If you have diabetes, liaise with the nurse to adjust your diabetic medications or insulin accordingly.

Can I eat before the procedure?

In most cases, you will be told to eat a normal meal the evening before your procedure. However, do not eat, drink or chew anything after 12 midnight before your procedure. This includes gum, mints, water, etc. If you must take medications, only take them with small sips of water. When brushing your teeth, do not swallow any water.

What should I wear?

When getting ready, please do not wear makeup and remove nail polish. Wear comfortable clothes when you come to the hospital. You will change into a hospital gown for the procedure. Please leave all jewellery (including wedding rings), watches and valuables at home.

What happens before the procedure?

Before the procedure begins, a nurse will help you get ready. You will be given a hospital gown to change into. You may keep your clothes in a locker or you may give them to a family member.

You will lie on a bed and the nurse will start an IV (intravenous) line in a vein in your arm or hand. The IV is used to deliver medications and fluids during the procedure.

To prevent infection and to keep the device insertion site sterile: an antibiotic will be given through the IV at the beginning of the procedure; the left or right side of your chest will be shaved; a special soap will be used to cleanse the area; sterile drapes are used to cover you from your neck to your feet; and a soft strap may be placed across your waist and arms to prevent your hands from touching the sterile area.

In rare cases, when the endocardial approach cannot be used, the epicardial (surgical) approach is used (more common in children). With this approach, general anaesthesia is given to put you to sleep during the procedure and the generator is placed in a pocket created under the skin in the lower abdomen.

The hospital recovery time is generally 3 to 5 days with the epicardial approach, although minimally invasive techniques may be used to allow a shorter hospital stay and quicker recovery time.

The doctor will determine which pacemaker implant method is best for you.

Who and where will the pacemaker implantation be done?

A specialist doctor called an Electrophysiologist will perform the procedure. The procedure will be done in the Electrophysiology Lab.

Is the procedure done under general anaesthetic?

A combination of local anaesthetic (to numb the implant site) and sedation will be used so you do not experience pain or undue discomfort during the procedure. Medication will be given through your IV to relax you and make you feel drowsy, but you will not be asleep during the procedure. Note that this is not open heart surgery; opening up the chest is not needed.

How long does the procedure take? What should I expect?

Most cases will take around 60 to 90 minutes.

You will be taken to a special area called the Electrophysiology Laboratory to have the pacemaker implanted:

You will lie on a bed and the Electrophysiology Lab staff will connect monitoring equipment to your chest. They will also start an IV (intravenous) drop in a vein in your arm or hand. The IV is used to deliver antibiotic medication and fluids during the procedure.

The doctor will then clean the chest using a special soap, and cover you using sterile drapes from your neck to your feet. He or she will then inject local anaesthetic to the skin and give you sedation before implanting the pacemaker.

The pacemaker is implanted through a small (approximately 5 cm) incision in the upper chest, usually on the left side. After the incision is made, the pacemaker "lead" is placed under X ray guidance into the heart; the pacemaker box is then connected to the other end of the lead and secured under the skin incision, in a little "pocket".

At this point, the doctor would test the device to make sure it is working properly. Once he or she is satisfied with the device, the skin will be sutured up and you will be woken up and returned to the ward.

How will the device be implanted?

The pacemaker is usually implanted using the endocardial (transvenous) approach. During the procedure, a local anaesthetic (pain-relieving medication) is injected to numb the area, and you will be awake during the procedure.

Small incisions are made in the chest where the lead (or leads) and device are inserted. The lead is inserted through the incision and into a vein, then guided to the heart with the aid of the fluoroscopy machine. The lead tip is attached to the heart muscle, while the other end of the lead is attached to the pulse generator. The generator is placed in a pocket created under the skin in the upper chest.

What kind of follow-up care do I expect after my device is implanted?

You will be required to come regularly for post-implant checkups whereby the cardiac physiologist will check your device with a programmer. During the routine checkups, the cardiac physiologist will:

• Review any heart rhythm events that may have occurred since your last checkup
• Ensure that your device functions are set to levels appropriate for your needs and if necessary, make any “fine tuning” adjustments
• Check the status of the battery that powers your device
• Answer any questions that you may have

Home monitoring service

The device monitor can interrogate, collect and transmit the information contained in your pacemaker to download the Cardiac Data for analysis.

The monitoring device facilitates early detection of asymptomatic events or changes in system integrity to ensure your well-being after implant. Based on the Cardiac Data received, your doctor can then arrange for follow-up care as needed.

With this service, the in-office device check will be replaced with remote monitoring. You will only be checked in-office when you come for your doctor visit.

FAQ

What is electromagnetic interference (EMI) and should I be concerned with EMI at my workplace?

Things that use electricity and magnets have electromagnetic fields around them and may cause Electromagnetic Interference (EMI). These fields are usually weak and will not affect your pacemaker.

However, strong electromagnetic fields have the potential to alter the function of your pacemaker. A strong magnetic field can "blind" the pacemaker to send pacing beats when your heart does not need it. If you move away from the source of EMI, your pacemaker will return to normal. Most office and shop equipment are unlikely to interfere with your pacemaker.

If you are uncertain, please do consult with your doctor.

Which devices interfere with a pacemaker? Is it a problem if I walk through airport, shopping or courtroom security metal detectors?

Airport screening devices are unlikely to affect your pacemaker but they may detect the metal housing of your device and set off the security alarm. If it does, inform the security personnel that you have a pacemaker implanted and show them your identification card.

Passing through the metal detector portal will not harm your device; however do not linger near it as the magnetic field may temporarily interrupt the normal function of the device.

Properly maintained electrical household items are unlikely to interfere with your pacemaker.

Are medical procedures safe?

Always mention to the medical personnel about your pacemaker implantation and show them your identification card. With proper precautionary measures prior to procedures, most medical and dental procedures are unlikely to interfere with your pacemaker except Magnetic Resonance Imaging (MRI), which is not recommended.

Alert your doctor if you are scheduled for medical procedures, including dental procedures, as your pacemaker may need to be reprogrammed before the procedure to lower the chance of interference or damage to the pacemaker's function.

My doctor has advised me to have a "scan". Is this safe if I have a pacemaker implanted?

Ultrasound scans (including echocardiograms), as well as X-ray scans (including CT scans) do not affect the function of your pacemaker; you may proceed with these normally.

However, you should not have MRI (magnetic resonance imaging) scans if your pacemaker is not MRI compatible. Please inform the doctor or radiologist prior to the scan.

Can I undergo Magnetic Resonance Imaging (MRI)?

You are able to undergo MRI only if your pacemakers are designed to be MRI conditional. Prior to the MRI scan, the cardiac physiologist will perform a pacemaker check and programmed the pacemaker to be in MRI safe mode. After the MRI scan is done, the cardiac physiologist will perform another pacemaker check and turn off the MRI safe mode, restoring its original parameters setting.

You will know if your pacemaker is MRI conditional through your pacemaker identification card. There will be an MRI safe logo on the pacemaker identification card. Alternatively, during the device check, cardiac physiologists are able to confirm if your pacemaker is designed to be MRI conditional.

Can I travel with my pacemaker?

Most people with pacemakers can travel freely unless they are restricted by their underlying medical condition or other unrelated conditions.

Can I use my mobile phone?

Mobile phones are unlikely to interfere with your pacemaker if proper precautions are followed. At least 6 inches should be maintained between your mobile phone and your pacemaker. When using your phone, you should hold it to the ear opposite the side of the body in which the pacemaker is implanted. When set to receive calls, your mobile phone should not be carried in a shirt pocket on the same side as the pacemaker.

What should my family do if I passed away at home?

Prior to cremation, the pacemaker has to be removed from the deceased as lithium batteries will explode when heated under high temperatures during cremation.

In the event of demise at home, the family member will have to call the General Practitioner/ Ambulance to certified death and removal of the pacemaker. Notification of Police is to be made by family member. The pulse generator needs to be completely removed and return to patient’s primary healthcare institution during operating hours.

Video on Cardiac Device Home Monitoring Service

Pacemaker Interference Quick Look-up Table

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