What is a Pacemaker and who needs one?
The normal heartbeat is produced by electrical impulses that begin inside a specialised part of the heart’s electrical system called the Sinus Node, which sits at the top of the right atrium. The electrical impulses then spread to all of the heart’s chambers through specialised electrical wiring and make the heart muscle contract. This ensures that enough blood and oxygen are pumped around the body to meet its demands. Any problems that affect the sinus node or the wiring may result in a slow heartbeat and cause symptoms like palpitations, breathlessness, tiredness, dizziness and blackouts. A pacemaker may then be required to restore the normal heartbeat and relieve the symptoms.
Pacemaker insertion is a minor surgical procedure that is performed under local anaesthetic with mild sedation. It takes about 60 minutes to do and most patients go home on the same day. There is a 1% risk of infection for which intravenous antibiotics are given.
A small, 3-cm cut is made under the collar bone (usually the left side). The pacemaker consists of one or two wires called “leads” that are positioned inside the chambers on the right side of the heart. They are introduced through the veins that run under the collar bone and guided into the heart using X-rays. The leads are connected to a small generator that sits under the skin below the collar bone and is the size of a large wristwatch. The generator is a small computer with a battery, electrical circuits and a memory chip. The battery lasts 10 to 15 years during which the pacemaker is constantly monitoring the heart’s electrical activity. Whenever the heart slows below a certain rate, the pacemaker switches on immediately and stimulates the heart muscle through the leads increasing the heart rate again. The generator also contains a motion sensor that tells the pacemaker to increase the heart rate in response to exercise.
The pacemaker is checked at least once a year in a special clinic to make sure it is working properly and to check the remaining battery life. This is done by either placing a sensor on the skin overlying the generator or by a wireless connection much like a mobile phone. A special computer called a programmer then checks the pacemaker and can adjust the pacemaker’s settings if necessary. When the battery starts to run down the old generator is removed and the leads reconnected to a new one.
Modern pacemakers are sophisticated devices that allow patients to lead full, active lives with few restrictions.