What is angina pectoris and Types of angina pectoris

Chest pain can be due to angina and a heart attack, a hiatal hernia, gas. Know the symptoms that characterize angina pectoris to identify and treat it as soon as possible

Angina is defined as pain, tightness, or discomfort, especially at the chest level, which is due to a lack of blood supply (known as ischemia) in the heart muscle, also called myocardium. This concept is exclusively clinical. That is, its diagnosis is based on the characteristics and circumstances that accompany the pain.

Causes of angina pectoris

The ischemia responsible for this condition is due to an imbalance between the myocardium’s oxygen demand and the contribution it receives from it. The most frequent cause of myocardial ischemia is the deposit of lipid materials (such as cholesterol ) in the arterial walls that nourish the heart, known as atherosclerosis.

Therefore, it can be said that angina pectoris is a clinical manifestation of the cessation of blood flow in the heart. As a consequence of this lack of oxygen, the heart muscle’s metabolism and certain properties of this, such as its elasticity, its contractibility, and others, are altered. 

In addition, there is also the release of certain substances that stimulate the nerve endings and cause the pain characteristic of myocardial ischemia. However, there are times when this lack of blood flow to the heart is not accompanied by pain, which makes the diagnosis quite difficult. In these cases, we speak of silent ischemia.

Angina pectoris is the most common initial presentation in patients with heart lesions due to blood flow deficit; that is, due to ischemic heart disease. But there are also other forms of manifestation, such as the well-known myocardial infarction and sudden death.

Difference between angina pectoris and myocardial infarction?

It is important not to confuse angina pectoris with a true myocardial infarction. Both are the cause of chest pain; the difference is based on the degree of occupation of the coronary vessel (they are in charge of carrying oxygen to the heart), causing the reduction in blood flow; being a total occupation in the infarction and partial in angina. 

This implies that in angina, the lack of oxygen is transitory, it causes the characteristic pain, but there is no death of the heart cells; that is, it is an alteration that reverses. 

However, in infarction, as it is a total obstruction, no blood reaches these cells for a variable time, but long enough for cell death (necrosis), thus making the lesion irreversible. 

According to the Society of Cardiology, three types of angina can be distinguished :

Exertional angina: is that pain caused by physical activity or any situation that involves exertion that involves a greater demand for oxygen by the myocardium. It is a pain that is usually brief and that disappears when the effort that originated it is interrupted or with nitroglycerin administration (vasodilator).

Angina at rest: occurs spontaneously, that is, without any relation to effort. Its duration is highly variable, being sometimes prolonged episodes of pain that resemble a heart attack. It is necessary to highlight a subtype that is variant, vasospastic or Prinzmetal’s angina, which occurs at rest, abruptly, and, especially, during night rest.

Mixed angina: in this type, all those forms are grouped where characteristics of exertional and resting angina coexist at the same time.

Another way to classify them much more practical is:

Stable angina: it would correspond to exertional angina in which its characteristics and the patient’s functional capacity (which reflects the ability of individuals to carry out activities that are part of their independent and productive life) have not changed during the last month. It is due to a reduction in oxygen supply temporarily and with good evolution.

Unstable angina: that of unpredictable evolution and variable prognosis; that is to say, we cannot know how it will evolve: if it will heal or progress to a heart attack. This term includes angina at rest and accelerated or progressive angina, which is angina on exertion that has worsened in terms of the number of episodes, the intensity of pain, or level of effort with which it appears. Due to a non-total obstruction in a coronary artery; It does not usually lead to complications, but it does have a worse evolution than the previous one.

Variant angina, vasospastic, or Prinzmetal’s: it is a variety of unstable angina that manifests abruptly and frequently during night rest. In contrast to unstable angina and infarction, the mechanism causing this problem is not the occlusion of a vessel but is due to spontaneous closure of the coronary vessel (vasospasm). 

The cause of this vasospasm is not entirely clear, although it is more common in smokers and people with high levels of cholesterol and blood pressure. It can occur in healthy coronary arteries or coronary arteries with atherosclerosis lesions. It can be unchained by the cold, emotional stress, consumption of certain medications or drugs such as cocaine. This picture is frequent in young people.

The prognosis of these patients depends fundamentally on the state of their coronary vessels. An important group of patients has a good evolution with long periods without symptoms. Another part of the patients has severe coronary artery lesions and constitutes a high-risk group, with an incidence of heart attack and death during the first year of 20% and 15%.