Artificial Cardiac Pacemakers

 Most importantly lives can be saved. An irregular heart beat is a life threatening condition and must be dealt with urgently. The American Heart Association indicates that 2.2 million Americans have some form of abnormal heart beat, some of which are minor, and some are life threatening. As shown by the graph below, age is an important factor in the functioning of the heart, including the functioning of the electrical system, as well as other aspects .This graph shows that there is a significant difference in heart failure cases in elderly people older than 60 years old. This is because, as the heart ages, the functions of the heart become less efficient. The aging process reduces the strength of the cardiac muscle, and also lessens the strength of electrical signals sent from the SA node.  Blood is therefore transported through the body less efficiently, resulting in lesser health. Aging increases the risk of many heart problems, including arrhythmia, strokes and heart failure, due to the weakened cardio-vascular system. It is therefore much more important for older people, anywhere over the age of 60 to regularly get check-ups, especially if experiencing any symptoms explained earlier. A possible solution to issues with the abnormal beating of the heart is a small device, called the artificial pacemaker.

The Artificial Pacemaker                                                                                                                                                          

A Pacemaker is used to treat many heart conditions where the electrical system of the heart is defective, including Bradycardia and Arrhythmia. It may be when the heart’s natural pacemaker (the SA node) is not functioning properly and has developed a heart rate that is not as it should be.  It is only ever used when the heart beats with an irregular rhythm (arrhythmia), or too slowly (Bradycardia). It is a small, electronic device that is implanted beneath the skin. It sends electrical signals through the heart that regulate an irregular heart beat or speed up a slow heart beat. An artificial pacemaker consists of two basic parts. A small battery powered unit, known as a generator and wires that connect the generator to the inner walls of the heart. Electrical impulses are sent from the generator through the leads to the inner walls of the heart. This causes the heart to contract, just as the natural pacemaker does. Theses electrical impulses are timed to flow at regular intervals, to regulate constant beating of the heart at an appropriate rate. Many pacemakers have a sensing function that stops the pacemaker from sending electrical impulses when the heart rate is above a certain level. This means the pacemaker is only active when it needs to be, when the heart rate is too slow. This type of pacemaker is called a demand pacemaker. Most pacemakers are internal (surgically implanted inside the body), however some are external (worn outside the body) and are only temporary solutions for heart problems.

How Pacemakers Are Implanted                                                                                                                        

Pacemakers are surgically planted internally, in the same position as the image shown below. Most often it is implanted beneath the collar bone, near the shoulder.  Pacemaker surgery is considered minor, with few risks involved. There are risks involved in any general surgery, such as a reaction to general anaesthetics, but they are considered minimal. The leads of the pacemaker are threaded through a large vein to the right ventricle within the heart. The generator is then connected to the wires and inserted beneath the skin. The surgery lasts for a few hours, and the patient just has to stay overnight and is then free to go. Some discomfort and swelling may be experienced the following week, but most people return to normal activities in just a few days.

Advantages of Using an Artificial Pacemaker (How the Needs of Humans Are Met)

The obvious advantage in using an artificial pacemaker is the improvement of the quality of life. This is because the pacemaker effectively replaces the electrical system in the heart (when needed) and regulates the heart beat to a set rate. It increases the heart rate if it falls too low by sending electrical impulses. This causes the heart to beat at a desired rate. With modern pacemakers (demand pacemakers) the heart rate can be controlled depending on what the person is doing. For example, when the person is doing physical activity, the pacemaker can adjust, increasing the heart rate to higher than usual. This ensures that enough blood and oxygen is supplied to the body to sustain physical activity. Also, the pacemaker can be turned off when a person goes to sleep, allowing their heart rate to fall as it would naturally. The heart rate can be adjusted to meet the needs of the user. This is important for the user to ensure that they can live a normal life as they usually would with a natural pacemaker. This artificial pacemaker improves the general health and quality of life for an individual because it allows them to perform physical tasks that they would not have been able to do before. Most often, patients can return to being completely active, with the exception of full contact sports, including rugby and wrestling.  These sports could damage the pacemaker. Swimming (in the image opposite) is often a recommended sport, as the body is not exposed to such forces due to the dense water environment.  It will remedy problems associated with arrhythmia, which includes dizziness (which could lead to fainting), light headedness and shortness of breath. The pacemaker also will improve concentration, as it improves the efficiency of the heart. This means more blood will be provided to organs such as the brain. Now that the brain has sufficient oxygen, it is able to perform at its full potential, hence concentration is improved. In many cases, the use of a pacemaker can save lives. A condition known as “complete heart block” can only be treated with an artificial pacemaker. It is a deadly condition, as the electrical system in the heart becomes completely blocked. This doesn’t allow any electrical impulse to b e conducted, therefore in many cases; the person’s heart does not beat at all. This will result in death unless treated immediately. The electrical impulses sent by the pacemaker are sufficient to initiate and sustain the beating of hearts with this condition. There are many serious conditions such as this (including severe arrhythmia and sudden death syndrome). In most cases the use of a pacemaker regulating a constant heart beat, these deaths can be avoided. According to the BBC news site, the use of modern, specialised pacemakers have the ability to halve the death rates in American hospitals. As technology progresses, pacemakers are now able to  treat heart failures, restoring the efficiency of the heart in pumping blood and therefore reducing mortality by approximately 51%.

Artificial pacemakers are also reliable devices that are known to not malfunction often.  They have been in use for 40-50 years, thus there has been a great deal of technological advancement. The first internal pacemaker was implanted into a patient in October, 1958. Remarkably, this patient is still alive now. These pacemakers can still malfunction, however it is very unlikely, and as technology progresses, reliability of these devices will also progress.

Disadvantages of Using an Artificial Pacemaker 

Although life is not significantly negatively changed, there are certain things that individuals with pacemakers must avoid.  As mentioned earlier, full contact sport (for example, rugby) must be avoided, as mentioned earlier. People with pacemakers must not be exposed to a strong magnetic field (including MRIs and some machines found in factories), , as this will interfere with the electrical circuit within it. If the electrical system fails in the pacemaker, the heart rate will no longer be stimulated by electrical impulses; therefore the heart beat will likely become abnormal again. This could have many disastrous effects, including death, or the return of old symptoms (such as palpitations or shortness of breath).  Also, interference from other electrical devices can cause the pacemaker to malfunction. Therefore, certain medical treatments must be avoided, including "electro cauterization” and “shock-wave lithotripsy” 

Many pacemakers contain private medical information about the person they are within. It is possible for strangers to access this private information wirelessly, and view these medical records.   This is a breach of privacy for the patient who owns the pacemaker. More shockingly, it is now also possible for other people to wirelessly change the artificial pacemaker’s programmed settings. This is a serious issue, as other people could have the ability to control the regulating of another’s heart rate. However, as technology advances, it is likely that pacemakers will become more secure with the private information that they hold.

A non significant disadvantage in having a pacemaker is that regular check-ups are required. This should not be a big issue, as it ensures that the pacemaker is functioning correctly and is maintaining the health of the individual using it.

However, a more serious issue is the use of pacemakers in very young children, including premature babies. The need for an alternative is most obvious here, as pacemaker leads do not grow with children. The children will need regular replacements of pacemakers. This is inconvenient, as they will have to be surgically operated on numerous times. It is possible, for some cases of arrhythmia for alternatives to internal artificial pacemakers being used.

Artificial Pacemaker Alternatives

For some abnormal heart rate conditions, alternative treatments are possible to using internal artificial pacemakers.  Often, medication can be used to treat abnormal heart beats. A medicine used to treat Bradycardia (abnormally slow heart beat, regularly treated with a pacemaker) is Atropine. Atropine is used to increase the heart rate, which therefore increases the amount of blood being pumped around the body. However Atropine is only a temporary solution and is not a long term fix.  Pacemakers are a long term fix and patients using medication to regulate heart rate may eventually need to have an artificial pacemaker implanted. Atropine can be used to treat Bradycardia only, as it increases the heart rate. It cannot regulate a heart rate that is irregular. A pacemaker can do this however, as well as treat Bradycardia. A pacemaker is a reliable device and provides the patient with much more control over their heart rate. “Demand pacemakers” can increase heart rate when necessary, for example during physical activity, when oxygen demands are higher. They can also be switched off when required to allow the heart rate to remain low during periods of rest. This is much more convenient and suitable for the patient. Atropine, however does not provide the patient with the same amount of control over their heart rate. It is a relatively cheap form of medication.  It only has one function; to increase the rate at which the heart beats. As already mentioned, Atropine is not a long term fix, yet internal pacemakers are. The price of getting an internal pacemaker implanted can be reasonably higher, however a large proportion can usually be covered by insurance. Overall, the choice of whether to use medication or get an internal pacemaker implanted depends on the type of arrhythmia, its severity, the costs involved and of course, personal choice.

Also, a particular type of surgery may be used to improve the cardiac electrical system. This surgery is known as “catheter ablation”. It is performed by a specialised cardiologist, known as an “electrophysiologist” (who deals particularly with irregular heartbeats).  A small puncture is made somewhere in the body, usually in the groin, then a flexible, thin tube (called a catheter) is inserted and threaded through the body to the heart. As mentioned earlier, a cause of Bradycardia is a blockage of the heart’s electrical pathways, causing an abnormally slow heart rate.  Once threaded inside the heart, the catheter is positioned to remove any damaged tissue within the heart that is preventing the electrical signal from being received. In the diagram below, a catheter is inserted in the groin, threaded through a tiny gap in the heart (known as the septal wall) and positioned to remove damaged tissue in the pulmonary vein. This procedure is very effective in restoring normal heart rate; however, not all forms of Bradycardia can be treated on this way. This is a valid alternative to a pacemaker, if it is suitable for the condition. Patients do not have to worry about magnetic fields, electrical devices or contact sports. However, this surgery is only valid when there is a blockage of electrical signals. There are many other causes of an abnormal heart rate, such as the malfunctioning of the “SA node”, all of which can not be treated with surgery.

Overall, artificial pacemakers are extremely useful devices used to treat the abnormal beating of the heart. They are used to save numerous lives and also to improve the quality of many also. They allow many people with heart problems to live a life with full participation in physical activity and much more. People with pacemakers generally have little significant change in their lives. They must only be wary of magnetic devices, large electric machines and contact sports such as rugby. This is a small inconvenience compared to the many advantages of using an artificial pacemaker. There are other valid alternatives to pacemakers, such as specific medications and surgery, yet pacemakers work for a much larger range of heart problems to do with the electrical system.

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