Cardiac pacemakers - Function & operation

What is a cardiac pacemaker?

A cardiac pacemaker is a small electrical device that is implanted under the skin in the chest wall. It acts as a pulse generator for the heart, monitors the heartbeat and is used for cardiac arrhythmias. 

How it works

The cardiac pacemaker is an electronic system in a micro format, which is powered by a battery. The device is equipped with a receiver and a transmitter. The receiver registers cardiac activity and records the heartbeat, and the transmitter emits electrical impulses to set the pace for the heart or take action in the event of imminent, dangerous cardiac arrhythmias. 

The cardiac pacemaker can also be used for diagnostic purposes. As the heartbeat is continuously registered and recorded, it is possible to identify cardiac arrhythmias that are difficult to document with a conventional ECG (electrocardiogram). 

Type of cardiac pacemakers

What types of cardiac pacemaker are available, and when are these used? Different cardiac pacemakers are used, depending on the cardiac arrhythmia or heart disease.

• The DDD pacemaker is a dual-chamber system with one electrode in an atrium of the heart and a second electrode in a ventricle. The pacemaker can, if necessary, give the heart an impulse or slow the heartbeat down. The frequency can thus be adapted to the patient’s needs and the strain on the heart.
• VVI pacemakers and AAI pacemakers are single-chamber systems with one electrode either in a ventricle (VVI) or in an atrium (AAI). Single-chamber systems are used for atrial fibrillation and impulse disorders in the sinus node. The sinus node is the heart’s own pacemaker.
• CRT cardiac pacemakers are triple-chamber systems with an additional electrode in the left ventricle. This can ensure that cardiac activity is better coordinated and the performance of the heart is improved. 

When is a cardiac pacemaker required?

A cardiac pacemaker is necessary for various diseases of the heart with cardiac arrhythmias.

Single-chamber systems are usually used for atrial fibrillation. These set the pace for an atrium that beats in an uncoordinated manner. If a conduction disorder from the atrium to the ventricle exists at the same time, a dual-chamber system is used.

Too slow a heartbeat, known as bradycardia, is the most common cardiac arrhythmia and requires the use of a cardiac pacemaker. Conduction disorders from the atrium to the ventricle (atrioventricular block), sick sinus syndrome and also atrial fibrillation are illnesses that can lead to bradycardia.

A pacemaker, which takes on the function of a defibrillator and immediately intervenes in the event of imminent ventricular fibrillation, is used for people who are at risk of life-threatening ventricular fibrillation or have already survived ventricular fibrillation. 

A cardiac pacemaker is sometimes also required after a heart attack or after heart surgery if the heart attack or surgery has impaired electrical signal transmission in the heart. Disruptions in the discharge rate between the left and right ventricles can occur with certain forms of cardiac insufficiency. A cardiac pacemaker is also used in such cases.

Cardiac pacemaker cost coverage

The costs for a cardiac pacemaker are assumed by mandatory basic health insurance. This also includes the regular inspection of the cardiac pacemaker.

Operation and aftercare

• The cardiac pacemaker is implanted under the skin. A small incision in the skin is necessary for this. The implantation usually takes place below the collarbone. The electrodes of the pacemaker are guided via a vein in the chest wall towards the heart and anchored there. The functioning of the pacemaker is then checked. If everything functions correctly, the incision is closed.
• The procedure normally takes place under local anaesthetic and takes around one hour. Patients can usually leave hospital on the day after the procedure.
• After the operation, you are given a pacemaker ID card, which you must always carry with you.
• The pacemaker needs to be inspected regularly to check it is functioning correctly. How often and at what intervals inspections take place depends on the type of pacemaker and the heart disease. At least one inspection per year is normally required. 

What needs to be taken into account immediately after the surgery?

Until the wound in the skin has fully healed, you should avoid causing excessive tension in the chest, for example by lifting loads. The wound should also be omitted from your personal hygiene routine for a few days. As it takes some time for the pacemaker and electrodes to become firmly embedded, you should still avoid strenuous physical activities in the beginning. 

What complications can occur after the cardiac pacemaker surgery?

The insertion of a cardiac pacemaker is a very common, routine operation. However, as with all surgery, complications may also occur in rare cases. The wound in the skin can become inflamed or bleeding can occur. Sometimes the electrodes are positioned incorrectly. Hiccups after the surgery or tingling in the arm may indicate an incorrect position. For VVI pacemakers, pacemaker syndrome sometimes occurs, with low blood pressure, shortness of breath and dizziness. In such cases, the electrodes must be anchored again or the pacemaker must be altered. 

Living with a cardiac pacemaker

You can generally lead a completely normal life with a cardiac pacemaker. You are usually even fitter after the insertion of the pacemaker than you were before. Life expectancy tends to be extended by the pacemaker rather than shortened. As it concerns an electronic device, you nevertheless need to pay attention to certain things in everyday life.

Everyday life

What must be kept in mind in everyday life? How to minimise risks.

• Alcoholic drinks can cause cardiac arrhythmias. You should thus limit the consumption of alcohol or ideally avoid it completely.
• Electronic devices induce magnetic fields. These may disrupt the functioning of the pacemaker. In particular, devices that contain strong magnets or produce strong magnetic fields can cause problems. After the surgery, you will receive detailed instructions on what you need to keep in mind and what you need to avoid. It is generally recommended to maintain a distance of 30 cm between electronic devices and the cardiac pacemaker.
• After the pacemaker is inserted, you are not allowed to drive for a week. If the pacemaker is being used after a cardiac arrest, you may have to wait longer until you can drive a car in order to ensure that there is no longer a risk. 

Travelling

In general, there are no restrictions when travelling. The pacemaker ID card must be presented at the airport as the device can trigger an alarm at the security inspection. Deep-sea diving below a certain depth can damage the pacemaker because of the water pressure. It is thus recommended that you do not dive any deeper than 5 m. 

Medical procedures

During future medical procedures that produce a magnetic field, do certain precautions need to be taken or do any safeguards need to be observed? Ultrasound and X-ray examinations are quite safe. During magnetic resonance imaging (MRI), the pacemaker may need to be protected or altered before and after the examination.