To pump blood around the body, the heart relies on an electrical stimulus. This stimulus is produced by specialised electrical tissue. If this tissue is damaged by disease, the electrical stimulus is disrupted and the heart cannot pump at the proper speed or strength.
The normal heart has its own pacemaker, which consists of specialised conducting tissue akin to nerves. The circuit consist of a small group of cells in the upper right chamber (right atrium) – the sinoatrial (SA) node. Impulses from this node are transmitted to the atrioventricular (AV) node, which is placed at the junction of the atria and ventricles. Transmission of impulses then go through to the ventricles via the so-called His bundle and Purkinje network of specialised conducting tissue. Disturbances in the generation and transmission of impulses through the conducting tissue of the heart leads to slow heart rhythms (bradycardias).
A cardiac pacemaker is a device that provides electrical stimulation to the heart. It consists of a box, which contains a battery and an electrical circuit and one or two leads. The box is placed outside the rib cage, under the skin, just below the clavicle. The leads are threaded through veins and the tips are anchored in the heart muscle.
Preparation for pacemaker implantation
• Let us know whether you are taking anticoagulants (eg. warfarin) or metformin, as you may need to stop these prior to the procedure.
• Take a bath or shower the night before and wash your chest, shoulders and armpits.
• Do not to eat for 6 hours before the test. You may drink water until one hour before.
• Please bring all your tablets in their original packets. All valuables should be left at home.
• You should be able to go home the day following the procedure. It is necessary to monitor the pacemaker at various times and your length of stay can only be decided at the time of the procedure. In case you need to stay overnight, bring your dressing gown, slippers and overnight toiletries. Please make sure that someone can collect you.
On arrival at the hospital
A nurse will take your blood pressure, temperature, pulse, height and weight. A doctor will take your medical history, examine you and take a blood sample. The procedure will be explained to you by a doctor and a nurse. This is an opportunity for you to ask questions and tell us any concerns you may have about the procedure.The doctor will then ask you to sign a consent form showing that you understand what is involved and agree to the procedure.
The procedure will be performed in the “Cardiac Catheter Lab”. The doctor will anaesthetise the area with local anaesthetic. You will feel a needle prick and a mild stinging sensation from the local anaesthetic but there is little or no pain during the procedure. Intravnous sedation can also be given to make you feel sleepy.
A small incision will be made on the upper part of your chest, just below the collar bone. A small pocket will be made through the incision to accommodate the pacemaker box. The lead or leads will then be threaded through one of the veins and the tips anchored in your heart. You will not feel the pacemaker leads inside the body, but you may feel extra heart beats as we introduce the leads into your heart.
After the pacemaker implantation
• Keep your wound clean and dry. Expect your shoulder to ache a little. You may take a painkiller if required, but be careful not to exceed the recommended dosage. Avoid lifting and manual work for 1 week. Also avoid raising your arm for 1 week.
• If at any time you notice new redness, soreness or oozing at the implantation site, please contact us directly, either through the secretary or the hospital ward.
• You will be given a brief letter for your GP. The stitches can be removed at 7-10 days. We will give you further instructions regarding this.
A new type of pacemaker is now available. This small capsule, the size of a pen drive, has no leads and which does not require surgery for implantation. The capsule is inserted into the heart via a small incision in the groin. The device is advanced through the femoral vein and anchored in the right side of the heart. The advantage is that no surgery is required to make a pacemaker pocket and that there is no lead attached. Potentially, this type of pacemaker does away with some of the complications of conventional pacemakers. Importantly, this type of pacemaker is not suitable for all patients. You will need to discuss this with the cardiologist.
The electrical system of the heart
A conventional pacemaker
A leadless pacemaker
Professor Leyva implants a leadless pacemaker
A pacemaker implantation