Angina is a heart condition caused by changes in the vessels of the heart, rendering it unable to respond to the blood demands of muscles during exercise. This causes uncomfortable pain until physical activity ceases.
The Basics
Angina causes the patient to suffer from pain, usually during physical exertion. The heart receives an insufficient volume of blood and, therefore, oxygen due to coronary artery narrowing as a result of atherosclerotic plaques. Angina comes in two types: stable angina and unstable angina. Patients with stable angina experience symptoms when undergoing physical exertion. The pain subsides a few minutes after ceasing physical activity. Unstable angina usually worsens and remains even after activity ceases or occurs at rest. Patients with these symptoms should be taken to the hospital immediately. Angina is an indication that the patient is likely to suffer from a heart attack unless remedial steps are taken.
Effects
During exercise, muscles need more energy, which is acquired through oxygen-dependent respiration. Oxygen is transported in the blood and so blood flow is increased to respiring muscles to meet the energy requirement. When the body exercises, epinephrine and norepinephrine are hormones released into the blood to stimulate the heart to contract faster and with more force, thus pumping more blood.
Symptoms
In their textbook "Medical Physiology," Arthur Guyton and John Hall describe how angina pain is often felt over the heart and also in more distant parts of the body, such as the left arm and shoulder, neck and side of the face. This occurs because of referred pain, in which pain fibers from the same segment of spinal cord terminate in each of these body parts. The brain is unable to differentiate which part of the body is experiencing pain. The pain is described as hot, pressing and constricting, leading the patient to cease all activity. Less common symptoms include breathlessness, nausea and stomach pain.
Diagnosis
An article exploring clinical practices when treating angina by Jonathan Abrams was published in the New England Journal of Medicine. One suggested form of non-invasive testing is to have the patient do some exercise and evaluate the heart using an ECG machine. Abnormal test results lead the physician to perform a coronary angiography, which is considered the gold standard for detecting coronary artery disease. Markers in the blood may also be measured such a C-reactive protein, which helps predict the progression of the disease.
Treatment
Two categories of drugs are prescribed for angina: anti-narrowing drugs and vessel-protecting drugs. Anti-narrowing drugs such as nitrates, beta-blockers and calcium channel blockers act to increase the diameter of the coronary vessels and decrease heart rate, allowing easier passage of blood. Often a combination of these drugs is prescribed, although certain combinations are discouraged as they cause low blood pressure. Vessel-protecting therapy involves lifestyle changes such as regular exercise, a healthy diet and cessation of smoking to improve the progression of angina and coronary heart disease. Vessel-protecting drugs such as aspirin and statins have also been proven to improve the progression. Other treatments that can be considered are surgical interventions that can improve the control of angina, such as angioplasties and bypasses, but these have not been shown to improve the risk of death among people with angina and coronary heart disease. These surgical options should be considered for people with lifestyle limitations or who have risk factors such as diabetes.
References
- New England Journal of Medicine; "Chronic Stable Angina"; Jonathan Abrams; June 16 2005
- Textbook of Medical Physiology; "Pain in Coronary Heart Disease"; Arthur C. Guyton, John E. Hall; 2005
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