What does your heart do?
The role of the heart is to pump blood to the entire body. Functionally, we speak about a left and a right side to the heart, although anatomically there is only one heart. Blood that has already passed through the body and is now oxygen poor (and carrying metabolic waste from the cells) arrives at the right side of the heart. This blood is pumped from the right side of the heart into the lungs, where carbon dioxide (a waste substance absorbed from the cells) is eliminated into the lungs. At the same time the blood absorbs oxygen from the air in the lungs. The blood is then pumped from the lungs to the left side of the heart. From there it is pumped through the arteries to the entire body. This oxygen-rich blood is called arterial blood.
The heart itself has four chambers:
- The right atrium and ventricle. Blood flows into the right atrium and is then pumped into the right ventricle.
- The left atrium and ventricle. Again blood flows into the left atrium and is then pumped into the left ventricle.
- There is no direct flow of blood between the right and left sides of the heart in a healthy heart.
What are the coronary arteries?
The structure of the heart is formed by a muscle called myocardium. The myocardium contracts and relaxes (beats) during its entire lifetime from the point it is created in the mother’s uterus. The rhythm of the beating depends on various factors which include age, whether the person is at rest or exercising, whether the person has a temperature or not, or if the person is healthy or not. In a healthy adult at rest or exercising moderately, the normal heart rate or cardiac rate (the quantity of heart beats per minute) is between 70 to 90 beats per minute. The work needed to pump blood some 70 to 90 times per minute represents a major use of energy. In order to supply the oxygen and the fuel (mainly glucose) needed for these contractions, the heart is equipped with a network of arteries, called coronary arteries, that carry oxygen-rich blood to the entire myocardium. In turn, venous blood, which is poor in oxygen, goes back to the right atrium through the coronary veins.
How do the coronary arteries get sick?
In a healthy person, the interior of the coronary arteries is wide enough to supply blood to the whole heart at rest and during normal or even very strenuous physical exertion. There are diseases affecting the coronary arteries which cause either blockages or other narrowing of the internal part of the coronary arteries. This narrowing reduces the amount of blood flowing into the myocardium or heart muscle. While the heart may receive enough blood at rest or during moderate exercise, the blood flow may be insufficient during more intense physical activities. The condition of blockages or narrowing of the coronary arteries is known as coronary atherosclerosis. This can be caused by high cholesterol levels, diabetes, high blood pressure, obesity, stress and/or smoking.
Coronary atherosclerosis occurs as a result of an accumulation of fat in the internal artery wall which builds up and narrows the interior of the artery. This is a very slow process which can take years. Coronary atherosclerosis can manifest itself in two ways:
- In a person who has had no symptoms at all, a total occlusion (or blockage) of the coronary artery can occur without warning, completely blocking the passage of blood to the heart. In this case, the heart (or myocardium) suffers a myocardial infarction – commonly known as heart attack– which causes damage or destroys all or part of the myocardial tissue.
- In other cases, the occlusion is not complete and the heart receives blood but less than is needed. This condition is referred to as angina pectoris. Patients with this condition are at risk of suffering a myocardial infarction in the future.
How does angina pectoris manifest itself?
Patients typically do not perceive angina pectoris necessarily as pain. There may be a vague discomfort in the precordial region (roughly speaking, the central part of the chest) which may rapidly turn into a severe and oppressive sensation. The discomfort is usually located in the center and towards the left side of the chest, behind the sternum (or breastbone) the bone in the middle of the chest.
The pain sometimes irradiates to the left and may reach the shoulder, the arm and even the fingers. At other times, this discomfort may radiate backwards, to the throat, jaw and even the teeth.
In some cases, the pain is perceived as extending to the right arm or to the abdomen. The heart rate may slightly rise and blood pressure is usually somewhat higher. Between one episode of angina pectoris and the next there may be no other symptoms of coronary disease.
Angina pectoris is typically triggered by physical exertion and lasts for only a few minutes. All symptoms usually disappear with rest. Angina typically appears as a response to a specific amount of physical activity although sometimes certain types of exercise are well tolerated one day while the next day they may trigger an episode. Circumstances that make angina worse include: exercising after a meal, cold weather, walking in windy weather or the first contact with cold air upon leaving a warm environment. Angina pectoris can also occur during sleep or while lying down.
What are the different types of angina pectoris?
There are three types of angina pectoris:
- Stable angina. As described above.
- Variant angina. Also known as Prinzmetal’s angina. It is produced by spasms occurring in the coronary arteries. It typically appears at rest and patients often feel an obstruction in at least one coronary artery. The spasm occurs close to this obstruction. It is common for the spasms to take place at the same time of day.
- Unstable angina. Also known as intermediate syndrome angina. It is characterized by a growing increase in the intensity of the symptoms already described for stable angina, the appearance of angina at rest or at night in patients who did not experience this symptom prior, or else the presence of a prolonged angina episode. This form of angina occurs due to an acute increase in the coronary obstruction.
Compared with stable angina, patients suffering from unstable angina are likely to experience more pain or more intense discomfort, pain or discomfort that lasts longer, is produced by lesser exertion, appears at rest, and is progressive (gradually increases in intensity during the episode). Not all of these characteristics necessarily manifest themselves: one or a combination of just a few of them may occur. This form of angina is the one that is more likely to result in myocardial infarction. These episodes must be treated in a Coronary Care Unit.
What tests are run to diagnose angina pectoris?
In addition to recognizing the symptoms and performing a physical examination, medical doctors typically prescribe an electrocardiogram (ECG) at rest and other complementary tests. In the absence of a positive diagnosis, physicians may prescribe a physical stress test: the patient sits on an upright bicycle or ergometer and starts pedaling while a gradual, growing resistance is applied to the pedals, requiring more exertion on the patient’s part. While this is happening, an ECG is performed on the patient. The ECG can reveal cardiac abnormalities that may occur even before the patient can feel the discomfort or the pain caused by the angina. This study confirms or rules out the presence of angina and gives the physician an idea of its severity.
What should be done when you have symptoms corresponding to angina pectoris?
If you are feeling these symptoms for the first time, you should immediately request medical assistance. If you have already been diagnosed with this disease by your physician, you should follow the directions that your physician has given you.
What is the treatment for angina pectoris?
General health and diet-related measures include getting back to a normal weight if the patient is overweight or obese and abstaining completely from smoking. Your physician may prescribe medication to be taken on a regular basis or when an episode of angina occurs depending on medical indications.
Regular medical check-ups are very important even for people without any symptoms of cardiac disease in order to diagnose and treat the condition before any of its symptoms may occur.