The coronary arteries are the vessels which supply blood to the heart itself. They are particularly prone to partial or total obstruction by atheroma—the process of fatty build-up caused by many factors, but principally excessive stress, sedentary living, smoking and an unhealthy diet.
Obstructed coronary arteries are the cause of heart attacks; and disease of the coronary arteries is the commonest cause of death in Western countries.
The Three Arteries.
The heart is a muscular bag which pumps blood round the body. Like any muscle, it must be supplied with oxygen and food to continue working. This supply is carried in the right and left coronary arteries, which are the first vessels to leave the aorta (the body’s main artery) as it emerges from the heart.
Almost as soon as it branches off the aorta, the left coronary artery splits into two big branches. So there are, in effect, three coronary arteries: the right and the two branches of the left. They go on to completely encircle and penetrate the heart, supplying blood to every part of it.
Except in a little proportion of cases, the disease process is always the same. Fat deposition build up on the wall of the artery, narrowing the whole artery and creating the risk of a total blockage.
The coronary arteries are particularly affected by the disease because, like the heart itself, they are always in motion and the resulting strain on their walls hastens the build-up of atheroma.
If a coronary artery becomes totally blocked, the blood supply to an area of heart muscle is shut off. There is a deep, heavy pain, often lasting for hours or even days, and described by the patient as resembling a vice-like grip. There is also shortness of breath, cold sweat, palpitations of the heart, and the patient looks very pale.
Eighty-five per cent of those who have a heart attack recover, but in some patients there is another, sometimes disastrous attack, in the first hour.
After the attack, the area of heart which was affected eventually heals into a scar known as a myocardial infarct. That part of the heart muscle will never work again. But with careful treatment, the patient will, in most cases, be able to lead a healthy, active life once more.
The blockage itself usually comes about as a result of what is known as a thrombosis (blood clot). The artery, narrowed by atheroma, restricts the flow of blood to such a slow pace that its natural tendency to clot or thicken begins to operate. This clot makes the final obstruction. A heart attack is, therefore, often referred to as a coronary thrombosis, or more commonly a coronary for short.
The further problem which coronary artery disease causes is angina. In this case, there is a partial block which allows the heart to function normally at rest but does not allow the extra blood flow necessary in response to exercise. In some patients the pain of angina is caused by intense spasm of the coronary arteries rather than actual physical blockage. This type of pain manifests itself at rest rather than during periods of exercise.
This relative lack of blood flow produces pain—the typical chest pain of angina which spreads to the arms, shoulders or neck. It is usually brought on by exertion or excitement and only lasts a few minutes. Patients who have angina may go on to develop a full-blown heart attack, and, conversely, patients who have had a heart attack may subsequently get attacks of angina.
Treatment of Coronary Arteries.
Angina can be a crippling disease even when the patient has not suffered heart attack. At its worst the patient may not be able to move more than a few yards without pain. Fortunately, modern treatment has made a considerable impact on preventing the symptoms that widen the coronary arteries. Patients can carry drugs about with them. When slipped under the tongue they quickly stop attacks, but are not very good at preventing attacks, as their effect only lasts for a few minutes.
There has, however, been a treatment for angina since the development of the beta blockers in the mid-1960’s- a great medical advance. These drugs block some of the effects (the so-called beta effects) of adrenalin. In doing so, they also reduce the amount of work the heart has to do and therefore its need for oxygen. Taken regularly, not just when there is pain, they reduce the number of angina attacks and probably help prevent heart attacks.
For people who are unable to take beta blockers because they have asthma, there is an effective alternative treatment with calcium channel blockers which also reduce the work load on the heart. These drugs are also used for treating angina.
The last 15 years has seen a considerable advance in surgery for the treatment of coronary artery disease. The surgeon removes a length of vein from the leg, and uses it to connect the diseased blood vessel directly to the aorta so that blood by-pass the obstruction.
Successful by-pass grafting depends upon very sophisticated surgical techniques. The joins must be able to withstand high pressures, and the blood vessels are only a few millimeters wide, but there is no doubt that it can be effective at relieving angina pains.
The reason why blood flow in coronary arteries becomes obstructed is still being extensively investigated, but one fact seems clear: blockage nearly always occurs when there is atheroma.
Death from heart attacks occurs for two basic reasons. First, the death of an area of heart muscle caused by the blocked artery causes a major disturbance of heart rhythm which reduces the efficiency of the heart so severely that it may stop working.
Secondly, if too much heart muscle is destroyed, the heart is simply not powerful enough to pump an adequate amount of blood around the body.
In contrast, relatively minor disturbances of heart rhythm— arrhythmias—can usually be treated with drugs or by electrical shock. If the timing sequence becomes totally interrupted and the heart slows, or even stops—known as heart block—it may be necessary to use a pacing system.
A wire is passed into a vein and threaded in the direction of the blood flow, until it becomes lodged against the wall of the heart. The other end of the wire is attached to a pacemaker implanted in the chest. This gives out a regular, electric impulse which drives the heart at the correct speed.
After one or two days in a coronary care unit, heart attack patients usually spend about ten days or two weeks in hospital, gradually regaining strength and resuming normal activities.
After leaving hospital most people can return to work within two or three months of a heart attack. Generally, patients are encouraged to resume an active and in every way normal life. There is no need to ‘protect’ the heart as though the patient is a permanent invalid, as lack of exercise was almost certainly a major cause of the heart attack in the first place.
Preventing Coronary Disease.
- Exercise regularly, and properly. Swimming, walking or jogging are ideal but don’t suddenly start doing violent exercise if you have been sedentary for a long time. Build up gradually, and if in doubt, ask your doctor’s advice. When you exercise, think about the exercise, not personal or work problems. If you are forced to sit at a desk all day, get up frequently, walk instead of drive, take the stairs, not the lift, and seek medical advice about programmed exercise which can be done by sedentary people without interrupting their routine.
- Eat a sensible diet. Go for a diet which cuts down intake of potentially harmful substances such as animal fats and carbohydrates. Information about this is freely available from health centres and books; but essentially you need to replace butter with certain types of margarine and use, say, sunflower oil for cooking, not animal fat. Try to omit sugar and starch and avoid large, heavy meals.
- Reduce mental stress. Stress is part of living, and your body is designed to put up with enormous amounts of stress. However, it was never intended to tolerate years of uninterrupted pressure, such as is part of all too many people’s business lives.
Coronary Disease—Are You At Risk?
- Smoker?—Ten a day doubles your chances of a coronary because nicotine in the bloodstream causes the arteries to go into spasm, thus narrowing them, making thrombosis more likely.
- Overweight?—Anyone more than 20 or 30% above the proper body weight for their age, height and sex is two to three times more prone to heart disease than the normal person.
- Stress?– If you’ve been under work or family pressures for a long time, a coronary may well be just around the corner.
- Desk-bound?– People in desk jobs who do not exercise properly are certainly more at risk than active people.
- High cholesterol level?—lf you eat large amounts, especially of dairy foods or foods containing animal fat, you are at risk and ought to adjust your diet.
- Family history?—lf heart disease runs in your family, don’t be alarmed—you’re not bound to have a coronary. But this should make you even more determined to avoid trouble by proper diet and exercise.
Frequently Asked Questions.
1. Could I have had a minor heart attack without knowing it?
Yes, It is fairly common to find clear evidence of a previous heart attack on the ECG (electrocardiograph) in patients who have never had any symptoms. These so-called ‘silent’ heart attacks are common in the elderly.
2. How old do I have to be before I’m at risk for a heart attack?
Heart attacks are occurring in younger and younger patients. They are very occasionally seen in patients in their teens and twenties. By the late thirties and early forties it is really quite common.
3. Does jogging lessen the risk of having coronary disease?
There is increasing evidence that H exercise requiring stamina gives some protection against coronaries. So jogging, cycling, swimming or walking is likely to be good for you as well as simply making you feel good. Muscle- or body-building exercises on the other hand are unlikely to give any protection unless they are part of a specially controlled gymnastic program. And if you have been sedentary throughout your life, do not suddenly start taking violent exercise; build up gradually.
4. Why is my angina much worse in cold weather?
Cold weather commonly makes angina worse, and it may become worse still if you do physical activity in the cold. It is, however, quite all right to do as much exercise after you are warmed up. The reason is connected with the fact that cold weather shuts down the circulation in the skin, increasing the resistance to the flow of blood, and the work the heart has to do.
5. I have angina, but my doctor says I shouldn’t take the beta-blocker drugs as I am asthmatic. Why is this?
These drugs are safe for most people but should not be used by those with asthma because they cause wheezing and breathlessness.
What actually happens when someone experiences a coronary thrombosis—in other words, a heart attack? And what are their chances of leading an active life again? Advances in medicine can do much to help sufferers, but prevention is always better than treatment.
Experienced in the field of nutrition, health, fitness, and more. She earned Master Degree from National Institute of Nutrition, Hyderabad and currently serving in the Eastern branch of ICMR. View author’s certificates.