What is angina pectoris?
Angina pectoris (Latin for chest pain) is pain that is caused by injury to the heart muscle (myocardium) during times of increased cardiac activity as a result of impaired blood flow and reduced oxygen supply. Angina pain is often described as a dull, constricting or crushing pain that is felt behind the sternum (retrosternal).It may also be described as a squeezing, burning or heaviness.
What does angina pectoris mean?
Angina pectoris is NOT a heart attack. As discussed below, angina pectoris is a sign of myocardial ischemia (injury to the heart muscle) and not a myocardial infarction (heart attack ~ death of heart muscle). This means you heart muscle is getting too little oxygen for its needs. However, angina pectoris often precedes a heart attack and can exist for months or years before a heart attack occurs. It should therefore be seen as a warning sign of an impending heart attack.
Angina pectoris is most commonly due to progressive narrowing of the coronary artery so if left untreated the attacks will get worse and more frequent until a person has a heart attack. Since the arm, neck and heart develop from the same embryonic tissue, angina typically causes pain to radiate to the arm, particularly left arm, and the neck. It tends to last for a few minutes and subside with rest or the use of nitrates.
Why does angina occur?
The myocardium of the heart is constantly working and pumps blood throughout the body by contracting and relaxing. Being such an active part of the body, it needs a constant supply of oxygen and nutrients, which means a good blood supply. As the activity increases, the heart has to work harder and faster. A slight restriction of the blood supply may not cause any symptoms or damage when at rest or with moderate activity.
However, if there is increased activity like during exercise, then the heart needs an intact blood supply with sufficient oxygen availability. If this is not available then the heart muscle tissue undergoes damage known as ischemia. The muscle does not die but is injured. If this injury is severe or persistent, it may lead to death to a portion of the heart muscle which is known as an infarct (myocardial infarction or heart attack).
Pathophysiology of Angina Pectoris
The coronary arteries of the heart supply oxygen-rich blood primarily to the heart muscle. These arteries have numerous branches to ensure that there is adequate coverage to the heart muscle. This is explained further under blood supply to the heart.
Clogged coronary arteries most often arises as a result of atherosclerosis. Here fatty plaques develop under the inner lining of the artery and is associated with high blood cholesterol, high blood pressure and cigarette smoking among other risk factors. The build up of these plaques gradually narrows the lumen of the artery over months or even years. It is usually asymptomatic meaning that a person does not know that is occurring because there are no symptoms.
Once the occlusion reaches a point where the blood supply to the heart muscle is severely impaired, it can cause pain during physical activity – this pain (angina pectoris) is a result of damage to the heart muscle. In severe cases, the blockage may be so severe and further compounded by the sudden lodging of a clot, that the heart muscle will die (heart attack or myocardial infarction).
Different Types of Angina
There are three types of angina :
- Stable angina or typical angina pectoris
- Prinzmetal variant angina
- Unstable angina or crescendo angina
Stable angina or typical angina pectoris is the most common form of angina. It occurs as a result of increased cardiac workload associated with physical activity or emotional stress. The narrowed coronary artery cannot deliver enough blood that is necessary for the heart’s needs and this causes injury as described above. The pain is relieved by rest or the use of nitrates. The process related to this form of angina is well understood.
Prinzmetal Variant Angina
This is an uncommon form of angina that occurs in episodes without any clearly defined trigger factors. It is not related to physical activity or emotional stress but is a consequence of a spasm in the coronary artery which worsens the narrowing already caused by moderate atherosclerosis. It also responds well to nitrates. This form of angina is less well understood when compared to stable angina.
Unstable angina, also known as crescendo angina, is a progressing form of angina that occurs with physical exertion and eventually even at rest. The frequency of pain increases, lasts longer with successive attacks and with time the person’s ability to undertake activity reduces significantly. It is believed to be a consequence of more than one factor – atherosclerosis, coronary artery spasm and possibly even a blood clot (thrombus or embolus) all at the same time. It tends to occur prior to a heart attack and is considered as a warning signal of an impending heart attack (myocardial infarction). Therefore it is also known as preinfarction angina.
Angina Signs and Symptoms
Angina pectoris is chest pain associated with injury of the heart muscle. This is due to a lack of sufficient oxygenated blood at a time when the heart has to meet with higher demands. Angina pain has a number of characteristics that can help to differentiate it from heart attack pain or heartburn. The latter, heartburn, is due to acid reflux and is frequently mistaken for angina. Symptoms are experienced by a person and is therefore subjective. Signs are clinical features that can be verified independently and often monitored accordingly.
Location of Angina Pain
The pain in angina pectoris is typically felt behind the breastbone (retrosternal) and sometimes may be more pronounced slightly to the left of the sternum. However, even pain on the right of the sternum can also be due due to angina. Typically the pain is described as a crushing or constricting pain. Patients may also describe the pain as burning or aching or even a tightness in the chest. Severe, sharp or stabbing pain is rarely due to angina – it is more likely due to conditions like pericarditis.
The pain tends to radiate to the arm and neck since the heart and these parts of the body develop from the same embryonic tissue. The more common presentation is for it to radiate to the left arm and left side of the neck. Sometimes it may also be reported to radiate to the epigastrium (the upper middle abdominal quadrant below the breastbone), jaw or back.
Duration of Angina Pain
Angina pain develops gradually and can last for 2 to 10 minutes. The intensity of the pain is usually proportional to the level of exertion – strenuous exercise causes severe pain while moderate exercise may cause mild pain. In most cases the pain subsides within 5 minutes usually with rest. In variant angina or even unstable angina, the pain may subside for no known reason or even be triggered at rest.
Pain associated with a heart attack on the other hand tends to last for more than 10 minutes and does not respond to rest. While angina pain can subside completely in a short period of time, it may recur within minutes if the same precipitating factors are present.
Triggers of Angina Pain
More common :
- Physical exertion
- Emotional stress or shock
Less common :
- Eating a large meal
- Cold weather
- Rest – unstable angina
- Lying down flat – variant or unstable angina
Other Signs and Symptoms with Angina Pain
The concomitant signs and symptoms may help to differentiate between angina and a heart attack. Breathlessness is often present in both cases and other respiratory symptoms like a cough or wheeze may also be present. Sweating, paleness (pallor), nausea, vomiting and fainting is more frequently seen with a heart attack although it may occur in angina but is usually mild if present.
Dizziness while present is severe angina is usually mild and never leads to fainting. Anxiety with an impending sense of doom is very prominent in a heart attack but is mild or absent in angina. However, the fear of a possible heart attack in angina often leads patients to become anxious and apprehensive about the pain.
Angina or Heart Attack Pain
Cardiovascular diseases that result in chest pain may be due to angina, myocardial infarction (heart attack), pericarditis or an aortic dissection. There are other possible causes, however, the presentation is usually not sudden and severe pain as it is with these conditions. Of these, angina is the most common and may occur as episodes over years before a heart attack ensues.
Differentiating between angina or a heart attack is crucial as the latter requires immediate medical attention. Some cases of angina that are not responding to medication or rest is also considered as a medical emergency since it is likely to leas to an infarct. However, many angina sufferers are sometimes confused as to when they should seek medical attention.
As a rule of thumb, any chest pain, whether mild or severe, that is persistent needs medical attention, especially if you have a history of heart disease. This is further supported by the presence of any, even one, of the signs and symptoms of a myocardial infarction (heart attack). These features are listed below.
Angina pectoris is the cardiac pain that is caused by a low oxygen supply (hypoxia) to the muscle tissue of the heart (myocardium). This reduced oxygen supply results in ischemia (cell injury). The pain is mild and lasts for anywhere from 2 minutes up to 10 minutes.
Myocardial infarction (heart attack) causes cardiac pain as a result of the death of heart muscle tissue. The pain is usually severe and typically lasts for more than 10 minutes.
In both angina and a heart attack, the sensation ranges from discomfort to pain in the center of the chest. Many other non-cardiac causes may also cause central chest pain and it is important to differentiate between cardiac and non-cardiac chest pain.
Angina vs Heart Attack
- Angina – behind breastbone (retrosternal)
- Heart attack – behind breastbone (retrosternal)
- Angina – arm, jaw, neck, middle of upper abdomen
- Heart attack – arm, jaw, neck, middle of upper abdomen
- Angina – exercise, strenuous physical activity, emotional stress
- Heart attack – spontaneous or exercise, strenuous physical activity, emotional stress
- Angina – rest, nitrates (nitroglycerin)
- Heart attack – unresponsive to rest or nitrates
- Angina – usually absent or may very rarely occur
- Heart attack – present in majority of the cases
Pale Skin (Pallor)
- Angina – not present or mild if so
- Heart attack – usually present
Dizziness and/or Fainting
- Angina – absent; mild dizziness may occur but not fainting
- Heart attack – common; severe dizziness and occasional fainting
- Angina – absent or sometimes mild
- Heart attack – severe (feeling of impending doom)
Nausea and/or Vomiting
- Angina – absent or may very rarely occur
- Heart attack – common
Last updated on August 17, 2018.