Due to the breadth of this subject and the constraints of this essay I will outline the following areas; what the disease is, the causes, preventative measures that can be taken to lessen the risk of heart disease, symptoms and finally what treatments are available.
What is heart disease? Coronary heart disease is the name used to describe the narrowing of the coronary arteries. The arteries that supply blood and oxygen to the heart muscle. Coronary heart disease can cause ischemia. Ischemia is when the supply of blood and oxygen to the heart muscle is inadequate; this often produces symptoms of angina and breathlessness. Coronary heart disease is often called ischemic heart disease or coronary artery disease. The narrowing of the arteries is usually the result of a mass of fat deposits and connective tissue building up in the inner walls of the artery. This is known as atherosclerotic plaque which causes atherosclerosis (3). This narrowing result in high blood pressure as the volume that can pass through the artery at any one time is greatly reduced. If the artery narrows too much it could completely block preventing the passage of blood. A blockage in one of the coronary arteries can lead to angina or a heart attack, while blockage in one of the arteries that supply blood to the brain will lead to a stroke. Smaller arteries are often affected first causing problems such as erectile dysfunction (in men) and poor circulation to the extremities.
One of the symptoms of heart disease is high blood pressure or hypertension. Hypertension is caused by a gradual increase in resistance to blood flow in the smaller arteries so that a high pressure is maintained even at rest. As a result of this the heart has to work harder which could result in the chambers enlarging so that it doesn’t pump blood effectively. Over 16 million adults in the UK currently have high blood pressure with at least a third of them being completely unaware (4) because it causes no symptoms and can only be detected when your blood pressure is measured by a doctor or nurse, because of this it is sometimes referred to as the ‘silent killer’. It is becoming an ever, increasing problem from middle age onwards killing over 60,000 people in the UK every year (4), this figure is still rising due to our lifestyles becoming more and more sedentary.
With heart disease being such a prolific killer it is important to understand what causes the disease and what preventative measures can be taken. There are a myriad of factors that affect your likelihood of getting heart disease one of the most important is genetics, have members of your family died from heart attacks or are currently suffering from heart problems. As there is no way to change your genetics the only thing you can do is make lifestyle and diet changes. Due to the link made between high levels of cholesterol in the blood and heart attacks the most obvious suggestion is to make a reduction in their cholesterol intake as it is the excess blood cholesterol which blocks the arteries. However it was found that the cholesterol that causes the damage is not the same as the one we eat, it is in fact the liver that produces this damaging cholesterol. So it is saturated fats that need to be reduced. People who have too much body fat are much more likely to develop heart disease and stroke even if they have no other risk factors. Obesity is unhealthy because excess weight increases the strain on the heart, not to mention bones and other tissues. Its link with coronary heart disease is mainly attributed to raising the blood pressure and blood cholesterol levels. Smoking is another contributing factor to the development of heart disease; it causes damage to the lungs resulting in the heart having to beat faster to get sufficient oxygen around the body. Smoking has also been linked to increasing the likelihood of fats to be deposited on the interior walls of arteries. Another contributing factor is the lack of regular exercise as there has been a tendency in recent years for people to become couch potatoes opting to sit around watching television and playing video games. It has been shown that even half an hour of brisk exercise a day such as walking can reduce the risk of coronary heart disease by up to 50% (3). Some heart disorders have now been found to be stress linked; ways of dealing with stress include light aerobic exercise and relaxation techniques. Atherosclerosis can be a long term problem associated with diabetes. For some people diabetes isn’t an option but for others, obese people are up to five times more likely to develop adult onset diabetes than people with a healthy weight and Body mass Index.
The symptoms of Coronary heart disease can range from simple breathlessness to sudden death with the latter being the most extreme, I will now briefly discuss the various symptoms relating to heart disease. With angina which is an acute narrowing of the blood vessels the patient may experience breathlessness and discomfort in the chest and arms usually when they exert themselves. Certain coronary artery disorders can cause abnormal or irregular heart rhythms whereas others can cause a severe slowing of the heart rate or even the heart to stop altogether this is known as a cardiac arrest. As with angina the symptoms of a cardiac infarction (heart attack) the patient experiences severe pain in the chest which can spread to the neck and arms (3).
Finally I would like to outline the treatments that are available to help combat heart disease. The most common suggestion made by a doctor when someone has been diagnosed hypertension which is normally a precursor to heart disease is a lifestyle change which may include weight loss, stopping smoking or regular exercise. This is normally the first option and can sometimes, lower blood pressure so that there is no need for drugs to be prescribed. The types of drugs that are prescribed normally aid the patient by:
- reducing the chance of blood clots developing
- increasing the blood supply to the heart
- reducing the work the heart has to do
- helping to keep blood cholesterol levels down
The drugs that are used include anti-platelet drugs (e.g. aspirin), nitrates, beta-blockers, calcium channel blockers and potassium channel activators and cholesterol lowering medicines to reduce the risk of having a heart attack.
Aspirin is used as it helps to prevent the blood from clotting by reducing the adhesive qualities of the platelets - the small blood cells that clump together to form a clot. The dose needed is smaller than the dose you would need for a headache. Aspirin is for treating patients with coronary heart disease, unless there are reasons for not giving it, for example an allergic reaction.
Nitrates are used to dilate blood vessels. They reduce the work of the heart and also help to widen the coronary arteries. They are administered as either a spray or in tablet form.
Beta Blockers, these drugs come in tablet form and they’re use was first discovered by Sir James Black, who won the Nobel Prize for Medicine in 1988 for his contribution in the development of Beta blockers (5). They act by slowing the heart rate. This reduces the amount of work the heart has to do, so that it needs less oxygen, blood and nutrients. In some cases calcium channel blockers are preferred instead of beta blockers where the patient is diabetic. Potassium channel activators work in the same way as nitrates as they relax the walls of the coronary arteries to improve blood flow.
Cholesterol (lipid)-lowering drugs may be administered to reduce the risk of a heart attack (3).
Drugs are the first line of treating heart disease but if the patient is beyond the help of drugs more invasive techniques may have to be used. There are hundreds of techniques but I shall describe two.
If it is found that the patient has shown a narrowing in an artery, it may be recommended that the patient undergoes coronary angioplasty. This is a treatment which improves blood supply to the heart muscle. A small inflatable balloon attached to a fine hollow metal tube (about the diameter of a human hair) is passed into an artery in either the groin or the arm. The device is then guided into the blocked coronary artery. The balloon is then inflated so that it pushes the plaque that is blocking the artery out of the way. The device may also contain a short tube of stainless-steel mesh, known as a ‘stent’. As the balloon is inflated, the stent expands so that it holds open the narrowed blood vessel. The balloon is then let down and removed, leaving the stent in place (2).
The technique of coronary angioplasty only works if the artery is narrowed or partially blocked. In the case of a complete blockage a coronary bypass is performed. In this operation a blood vessel (usually a vein removed from the leg) is grafted between the aorta and a point in the coronary artery beyond the blocked area. In cases of complete heart block and heart rhythm disturbance an artificial pacemaker may be used. Pacemakers are used to maintain and correct the rhythm of the heart and are used either continuously or on demand (2).
In conclusion it is clear to see that coronary heart disease is a major killer but through correct diet and healthy lifestyle it is an easy killer to evade. One can also see that with the ever increasing numbers of obese children the problem will not go just disappear, the problem needs to be tackled head on with correct advertising and education. In my opinion the preventative measures of living a healthier lifestyle seem a whole lot easier and less painful than living with the disease.
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Bibliography
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Westcott, P. BBC.co.uk-Health (2004)
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Martini, H.M, Bartholomew, E.F. Essentials of Anatomy and Physiology (2003) Pearson Education, Inc. USA ISBN 0 13 110312 1
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The British Heart Foundation (2004)
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McGregor, G. Chairman of the Blood Pressure Association and Professor of Cardiovascular medicine, St. George’s Hospital, London. Ease The Pressure (March 2004) Article, Men’s Health, March 2004 page 115.
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Roberts, M. Reiss, M. Monger, G. Advanced Biology (2000), Nelson, Spain ISBN 0 17 438732 6