- Angina is a reversibel ischemic (reduced blood flow to the heart muscle) event in contrast to a heart attack or myocardial infarction, which is an irreversible ischemic event causing permanent damage to the heart muscle. Angina is can be classified as:
- Stable Angina / Angina Pectoris - Chest pain due to plaque build-up in the coronary arteries due to atherosclerosis causing reduced blood flow to the heart muscle. Stabel angina occurs when there is more demand of heart, such as during physical exertion, but also during emotial stress, exposure to very hot or cold temperatures, and heavy meals. Unlike unstable angina, stable angina doesn't come as a surprise, and episodes of pain tend to be alike, usually lasts 5 minutes or less, is relieved by rest or medicine and can sometimes be misdiagnosed as gas or indigestion. The chest pain sometimes spreads to the mandible, arms, back, or other areas. This condition is part of a wider sets of conditions known as coronary heart disease (CHD) or coronaryary artery disease (CAD).
- Unstable Angina - Unexpected chest pain because of reduced blood flow to the heart muscle when the coronary arteries narrow due to atherosclerosis. Artherosclerotic plaques can rupture, which blocks the flow of blood to the heart muscle in more distal sites. Unstable angina commonly occurs while resting. This condition is sometimes referred to as acute coronary syndrome. Unstable angina is a medical emergency and can lead to a heart attack.
- Variant (Prinzmetal) Angina - Very painful attacks caused by a spasm in the coronary arteries that almost always occurs when a person is at rest, usually between midnight and early morning. This condition is also referre to as Variant angina, Prinzmetal's variant angina, or Angina inversa. Prinzmetal’s angina is rare, representing about two out of 100 cases of angina, and usually occurs in younger patients than those who have other kinds of angina.
- Microvascular Angina - Reduced blood flow to the heart muscle due to spasms of small arterial blood vessels within the walls of the heart muscle. Chest pain usually lasts longer than 10 minutes, and it can last longer than 30 minutes. Other symptoms, such as shortness of breath, sleep problems, fatigue, and lack of energy may also be present.
The Canadian Cardiovascular Society Classification of Angina Pectoris
The Canadian Cardiovascular Society Classification of Angina Pectoris separates patients with anginal symptoms into groups based on the severity of their symptoms. The classification uses the extent of limitation on daily activities and the kind of physical activity which precipitates the anginal episode.
|No limitation of ordinary activity.||Ordinary physical activity (such as walking or climbing stairs) does not cause angina. Angina may occur with strenuous rapid or prolonged exertion at work or recreation.||I|
|Slight limitation of ordinary activity.||Angina may occur with|
• walking or climbing stairs rapidly;
• walking uphill;
• walking or stair climbing after meals or in the cold in the wind or under emotional stress;
• walking more than 2 blocks on the level at a normal pace and in normal conditions
• climbing more than 1 flight of ordinary stairs at a normal pace and in normal conditions.
|Marked limitation of ordinary physical activity.||Angina may occur after|
• walking 1-2 blocks on the level or
• climbing 1 flight of stairs in normal conditions at a normal pace.
|Unable to carry on any physical activity without discomfort.||Angina may be present at rest.||IV|
The Braunwald Classification of Unstable Angina facilitates the assignment of patients to a particular risk group according to the severity of symptoms, the clinical circumstances surrounding the anginal episode, and the intensity of treatment.
|Develops in presence of extracardiac condition that intensifies myocardial ischemia (secondary UA)||Develops in the absence of extracardiac condition (primary UA)||Develops within 2 weeks after acute myocardial infarction (postinfarction UA)|
|I||New onset of severe angina or accelerated angina; no rest pain|
|II||Angina at rest within past month but not within preceding 48 hr (angina at rest, subacute)|
|III||Angina at rest within 48 hr (angina at rest, acute)|
IIIB Troponin negative
IIIB Troponin positive
- Balla C, et al. Treatment of Angina: Where Are We? Cardiology. 2018;140(1):52-67.
- Blumenthal DM. Prevalence of angina among primary care patients with coronary artery disease. JAMA Netw Open. 2021;4(6):e2112800.
- Ford TJ, et al. Angina: contemporary diagnosis and management. Heart 2020;106:387–398.
- Kloner RA, et al. Angina and its management. J Cardiovasc Pharmacol Ther. 2017 May;22(3):199-209.
- Levy BI, et al. The many faces of myocardial ischaemia and angina. Cardiovasc Res. 2019 Aug 1;115(10):1460-1470.