Pacemakers
Why you may need a pacemaker
When to see a cardiologist
How a pacemaker works
The pacemaker implant procedure
Living with a pacemaker
Complications of a pacemakers
Why you may need a pacemaker
Pacemakers are common medical devices used to treat cardiac conduction abnormalities and heart rhythm disorders. Around 50,000 people in the UK are fitted with a pacemaker every year.
Common reasons for needing a pacemaker include a heartbeat that is too slow (bradycardia). This commonly arises from conduction system disease (particularly disease of the atrioventricular node) and sinoatrial conduction disease, sometimes known as “sick sinus syndrome”.
Some fast arrhythmias such as atrial fibrillation, atrial flutter and atrial tachycardia may also be treated with pacemaker implantation. This option is typically used when other measures to correct a fast heart rhythm have failed or are unlikely to succeed long term. In this case, pacemaker implantation may be undertaken in combination with drug treatments or a procedure called AV node ablation, to ensure that the pacemaker regulates the heart nearly 100% of the time.
Pacemaker implantation increases with age, with a notable rise among individuals over 65 years. This is partly due to conduction system disease increasing with age, but also older people may not be suitable for some of the other,more invasive, arrhythmia treatments such as ablation, and pacemakers may be offered as an alternative.
When to See a Cardiologist
Symptoms of a slow heartbeat include breathlessness, dizziness, lightheadedness, and in the most severe cases even passing out. These symptoms can be constant or intermittent.
Bradycardias and other heart rhythm problems can also be present without causing symptoms. Some slow heart rhythms are only important if they are causing symptoms. Other bradycardias (for example some “heart blocks”) carry risks even if symptoms are not present.
A cardiologist - in particular a heart rhythm specialist (electrophysiologist) - has access to a range of tests to confirm that symptoms are caused by an abnormal heartbeat. Tests can also be used to tell whether a slow heartbeat is risky or not. Tests that may be used include ECG, echocardiogram, ECG Holter monitoring and ECG during exercise.
How a Pacemaker Works
Most pacemakers consist of a number of insulated wires (“leads”) that pass down veins into the heart and fix to the internal surface of one of more heart chambers. The leads are wired into a small computer and battery pack (“generator”) that sits under the skin or muscle near to the left or right shoulder. Many different variations on this basic setup exist, including different numbers of leads and different positions for the generator, depending on what problem is being treated.
The fundamental job of all pacemakers is to guarantee a minimum heart rate. The computer inside the generator “listens” to the heart’s electrical activity via the leads, and if a beat does not occur within a certain time from the last beat, the generator sends a pulse of electricity down the lead to trigger a heartbeat. For example, if a generator is programmed to deliver a beat after waiting for one second from the last one, then this will guarantee a minimum of one beat per second, or 60bpm.
Almost all modern pacemakers are far more sophisticated than this basic description; using multiple leads in different heart chambers they can re-coordinate the heartbeat and ensure, for example, that the top chambers (“atria”) always beat before the lower chambers (“ventricles”). Some pacemakers can also help the heart beat more strongly, to help treat conditions such as heart failure.
The Pacemaker Implant Procedure
Pacemakers may be fitted electively, or as an emergency procedure. Most elective pacemaker implant procedures will be done as day case procedures (i.e. without a night in hospital) and with the patient awake but sedated.
As one of the main risks of pacemaker implantation is infection, a lot of care is paid to cleaning the skin and maintaining sterility of the surgical area using surgical drapes. The drapes will be arranged to prevent the patient from viewing the procedure.
An injection is used to numb an area high on the chest, near to one or other shoulder. Once the area is numb a 3-4cm cut is made to the skin through which the rest of the procedure is carried out. Most of the procedure should be entirely painless but the stage where a space is made for the generator to sit under the skin can be uncomfortable. This is usually very brief, however (over in well under a minute).
A basic pacemaker implant procedure will usually take around an hour. Antibiotics are given beforehand and a dressing applied at the end of the procedure. Checks are done on the device both during and after the procedure, and waiting for these checks is a common reason why discharge from hospital may be later than anticipated: it is important to give time for any problems to become obvious.
Living With A Pacemaker
Early after a pacemaker implant there are a short list of restrictions on activity to help minimise the risk of the pacemaker leads becoming displaced. These are mostly common sense measures such as avoiding lifting the arm on the affected side above horizontal, avoiding carrying heavy items on that side, and so forth. Generally these restrictions last a few weeks at most.
Golfers may be asked to take an extended break from playing because the golf swing involves extreme movements of the arm, clavicle and shoulder joint, all of which can impact on the leads and generator, and cause them to displace.
Until the cut used to implant the pacemaker has healed, patients are asked not to get moisture on or near the wound.
Overall around 1/20 patients with a pacemaker will need a second procedure early on after the implant to fix a problem. The majority of these are to fix leads that have become displaced.
Over the longer term, once the leads and generator have scarred firmly into place and the cut has healed fully, there are relatively few restrictions on living with a pacemaker. Most of the genuine concerns relate to magnets and magnetic fields that can interfere with the programming and function of the generator.
Due to shifts in technology the precise advice changes frequently. The British Heart Foundation maintains a useful list of dos and don’ts here.
You can also access BHF’s latest advice on pacemakers and induction hobs here.
Complications of Pacemakers
Most of the complications of having a pacemaker relate to the implant procedure. Global figures show that one in 20 people will require a second procedure to fix a problem related to the first implant procedure; the majority of those will be to reposition leads that have moved in the heart. More serious complications also occur but tend to be much rarer.
Long term, the main complications of pacemakers are mainly related to the leads, which can malfunction or degrade over time. Battery change operations, as well as the original implant procedure, carry a small risk of infection but this climbs with the number of battery change procedures.
The area of pacemaker complications receiving most attention currently is pacemaker-mediated cardiomyopthy. This is a syndrome where long term reliance on a pacemaker for most or all of their heartbeats are at risk of developing weakness of the heart muscle over the long term. Techniques termed “physiological pacing” have been developed to minimise the chance of this happening and Dr Harding has been leading the introduction of these techniques in Kent.