What is a pacemaker?
A cardiac pacemaker is a device used to treat slow heart rhythms. When the heart beats too slowly this can lead to blackouts or reduce a person’s ability to exercise. A pacemaker monitors the heart rate and if it detects that the heart rate is abnormally low, it stimulates the heart with a small electrical impulse which causes it to beat. Please see the section on “normal and abnormal heart rhythms” for a better understanding of the normal heart beat. Abnormally slow heart rates can be caused by disease of the sinus node (the heart’s natural pacemaker) or disease of the heart’s “electrical wiring” (the AV node and His bundle) so that impulses from the upper part of the heart are not conducted to the large pumping chambers in the lower part of the heart.
The pacemaker consists of a small metal box (or pulse generator), smaller than a match box with between one and three leads. The leads are flexible, insulated wires which connect the pulse generator to the heart. The end of the lead contains a device to fix it to the heart muscle. This usually consists of a small metal screw, or occasionally, flexible, soft, plastic tines (like hooks). The pulse generator contains a battery which lasts between five and twelve years. Modern pacemakers are what is known as “demand” pacemakers, that is the pacemaker only stimulates the heart when the heart beats too slowly; If the heart rate is adequate the pacemaker simply watches and does not stimulate the heart. Most pacemakers can detect when a person is exercising and can increase the heart rate appropriately.
How is a pacemaker implanted?
Pacemakers are can be implanted under local or general anaesthetic. The doctor makes a small incision underneath the collarbone, usually on the left side, and a lead (or leads – up to three might be used) is then inserted into a large vein beneath the collarbone and passed along the vein into the heart. The pacemaker uses the lead to sense the heart rhythm and to deliver electrical stimuli to cause the heart to beat. The lead is attached to the pulse generator and the wound is closed with sutures. The sutures or stitches are absorbed by the body and do not need to be removed.
What are the risks of implanting a pacemaker?
The risks include death (less than 1 in 1000 cases), infection (less than 1% of cases), bleeding (risk of serious bleeding less than 1%) and pneumothorax or collapsed lung (less than 1% of cases).
What is the recovery period after pacemaker implantation?
Even though the wound is covered with a waterproof dressing, we recommend you do not allow the wound to become wet until the dressing is removed 7-10 days after surgery. We also recommend that you do not perform vigorous arm movements or raise the arm on the side of the pacemaker above the level of the shoulder for four weeks after the implant surgery. This is because it takes some time for the lead to become properly attached to the heart muscle and excessive arm movement can dislodge the lead. You can move the arm on the opposite side to the pacemaker normally. It is important to not keep the arm rigidly by the side as this may cause the shoulder to become stiff. Your doctor will show you some gentle movements you should use to exercise the arm on the side of the pacemaker. In Australia it is illegal to drive a motor vehicle for two weeks after a pacemaker is implanted.
Will the pacemaker restrict my activities?
In general, people with pacemakers can undertake normal activity. However, patients with pacemakers should not perform electrical welding. This is because the welder can inhibit the pacemaker and temporarily stop it from functioning. This could result in a blackout or faint. Most other activities can be undertaken normally. Pacemakers may cause the metal detector at airport security points to sound an alert. If this happens you should explain to the attendant that you have a pacemaker and the security person will use a special device to check for other metallic objects. The airport metal detector will not harm the pacemaker. Mobile phones, electric blankets, microwave ovens and shock security symptoms do not usually cause problems with the pacemaker.
How long does the pacemaker battery last?
Pacemaker batteries usually last between five to ten years. Pacemakers are usually replaced when there is more than three months of battery charge remaining. The battery level can be monitored by your doctor using an electronic device.
What about remote monitoring?
Some pacemakers are capable of being connected to a device which will send a message to your electrophysiologist if a problem develops with the pacemaker. This is called remote monitoring. These devices are usually placed in your bedroom (for example under the bed or on a bedside table) and communicate with your pacemaker on a regular basis. If a problem is detected, a message is sent over the mobile phone network or over a landline. However, these messages are not monitored on a 24/7 basis and it may be 24-72 hours before the message is received. These devices do not remove the need for regular checks with your electrophysiologist or cardiologist, although it may be possible to increase the interval between these checks. In addition, if a problem is detected by the monitor which requires the pacemaker to be reprogrammed it will be necessary to visit your electrophysiologist since the pacemaker cannot be reprogrammed using the remote monitor.
Can I have an MRI scan if I have a pacemaker?
Most modern pacemakers and leads are “MRI compatible”, in other words it is safe to have an MRI scan if you have one of these pacemakers. Older pacemakers may not be MRI compatible or may not have been tested for MRI safety. Careful planning is essential before performing a MRI scan since it may be necessary to have technician present during the scan and the pacemaker’s program will need to be adjusted so that the scan can be performed safely. Lastly, MRI scanning in patients with pacemakers is a relatively new procedure and not all MRI centres have developed protocols; these centres may not be prepared to perform the scan.
© Dr Mark McGuire 10.01.2018 (Version 1.0)