The heart is a pump responsible for maintaining blood supply to the body. It has four chambers. The two upper chambers (the right atrium and left atrium) are the chambers that receive blood as it returns from the body via the veins. The lower chambers (the right and left ventricle) are the chambers responsible for pumping the blood out to the body via the arteries. Like any pump, the heart has an electrical system that controls how it functions.
In order for the heart to do its work (pumping blood throughout the body), it needs a sort of spark plug or electrical impulse to generate a heartbeat. Normally this electrical impulse begins in the upper right chamber of the heart (in the right atrium) in a place called the sino-atrial (SA) node. The SA node is the natural pacemaker of the heart. The SA node gives off electrical impulses to generate a heartbeat in the range of 60 to 100 times per minute. If you are exercising, doing strenuous work or are under stress, your heart rate will be faster. When you rest or sleep your heart rate will slow down. If you take certain medications, your heart rate may be slower.
From the Sinus Node, the electrical impulse is relayed along the heart’s conduction system. It spreads throughout both the right and left atria causing them to contract evenly.
When the impulse spreads over the right atrium it reaches the atrio-ventricular (AV) node. This is a very important structure in the heart because it is the only electrical connection between the top chambers and the bottom chambers. It is therefore the only way in which an electrical impulse can reach the pumping chambers (the ventricles). The impulse spreads through the AV node and down into the lower chambers or ventricles of the heart. This causes them to contract and pump blood to the lungs and body.
In some people the electrical system of the heart may stop working properly. This can occur in a number of different ways. Sometimes the SA node fails to make enough impulses and the heart slows down and even pauses. This is sometimes called “sick sinus syndrome”. On other occasions, even though the SA node is making enough impulses, there are problems with either the AV Node, or the left and right bundle branches. When this happens, the impulses are not conducted down into the pumping chambers. This is termed “heart block” (This doesn’t mean there are blockages in arteries but rather in the electrical system). This will also cause the heart to slow down or pause.
When the heart slows down or pauses symptoms may include tiredness, breathlessness or lightheadedness.
However, commonly when the heart pauses, you will experience dizziness or actually pass out and collapse. You may experience very little or no warning prior to collapsing
Insertion of a pacemaker is a very common procedure. This is performed under local anaesthetic with sedative medication to make you feel comfortable. The procedure takes approximately 1 hour and is performed in the cardiac catheter laboratory.
This is a special room that has a patient table, X-Ray tube, ECG monitors and other equipment. The staff in the lab will all be dressed in hospital theatre clothes and during the procedure will be wearing hats and masks.
Many ECG monitoring electrodes will be attached to your chest area. A nurse or doctor will insert an intravenous line usually into the back of your hand. This is needed as a reliable way to give you medications during the study without further injections. You will also have a blood-pressure cuff attached to your arm that will automatically inflate at various times throughout the procedure.
The pacemaker is inserted just under the collar-bone on the front of the chest usually on the right side (it can also be implanted on the left side). The area is prepared with a special sterile solution that may feel cold. You will be covered by a large sterile sheet that will partly cover your face. You will be able to look out from under the sheet to the side and a nurse will be present at all times. You will be given oxygen to breathe by a small tube that is positioned under your nostrils or by a mask that covers your face.
At the start of the procedure, the doctor will inject local anaesthetic into the area under the collar-bone where the pacemaker is to be inserted. This will sting momentarily but the area will then be numb. During the procedure you may feel some firm pushing in the shoulder area but this should not be painful. If you experience pain or discomfort you should tell the nurse or doctor.
Usually 2 leads (special wires which connect the pacemaker with the heart) are inserted into the heart via the vein under the collarbone. These are manipulated into the heart under X-Ray control. Most commonly 2 leads are inserted, one into the right atrium and one into the right ventricle. These leads attach to the heart wall either with small hooks or with a small screw. Depending on your heart problem sometimes only 1 lead is inserted and on other occasions it will be necessary to add a third lead. Your doctor will discuss this with you.
You will receive a letter from the hospital bookings clerk or from the Doctors secretary outlining the date of your procedure and date and time of your admission to the hospital.
If you are taking anti-coagulation (blood thinning) medication eg warfarin then you will need to stop this for approximately 5 days prior to your procedure. Your doctor may arrange for you to have daily heparin injections after you stop the warfarin.
Patients having the procedure at the Royal Melbourne Hospital will be required to attend the pre-admission clinic on the day prior to the procedure.
Some country patients may need to make arrangements to stay overnight with family or friends.
At the pre-admission clinic you will see a doctor who will record your medical history. You will also require an ECG and blood test. The doctor will also confirm the time you should be at the hospital for admission the following day.
You will be required to fast for at least six hours before each of the procedures. If your procedure is in the afternoon you may have a light breakfast. If your procedure is in the morning, DO NOT EAT OR DRINK AFTER MIDNIGHT, except for sips of water to help you swallow your pills.
After the procedure you will have some bruising and discomfort in the area of the pacemaker that may persist for several weeks. This bruising can create a bluish discolouration over the upper chest and arm. This is normal.
You should avoid strenuous activities with your arm or from lifting the arm above your head for a period of 4 weeks. You should refrain from driving for 2 weeks. If you have already had a heart rhythm disturbance you may be disqualified from driving for 6 months. Your doctor will discuss this with you. You should not go swimming, play golf, or bowling for 4 weeks.
A sterile dressing is left over the pacemaker for 6 days. The dressing is waterproof and you can shower with it on. You can carefully remove this dressing yourself on the 6th day after the procedure. At this stage the wound is sufficiently healed to allow you to shower with the dressing removed.
You will be allowed to go home 1 or 2 days after the procedure.
You will be given an appointment to see the doctor 1 month after the implant.
Usually the discomfort and swelling from the wound settles gradually over several weeks. If the wound becomes increasingly tender reddened and swollen or you have any other concerns, you should contact us.
Pacemaker implantation is a very common and low risk procedure and should a complication arise, it will be dealt with at once.
Although most people undergoing defibrillator implantation do not experience any complications, you should be aware of the following risks: