Pain in the chest is a common complaint that has many causes, ranging from mild causes such as muscle…
- Angina is chest pain due to the heart muscle not getting enough oxygen.
- Angina is usually caused by the narrowing of the arteriesthat supply blood to the heart itself.
- The goal of treatment for angina is to reduce the symptoms and to help manage risk factors. Treatment can include lifestyle changes, medications, and surgery.
What is angina?
Angina pectoris, or angina for short, occurs when there is poor blood supply to the heart muscle, resulting in chest pain.
Angina is usually caused by the narrowing of the coronary arteries, which are the blood vessels that supply the heart. Plaques, which are deposits made mainly of fat and cholesterol, build up in the artery walls, causing the arteries to harden and narrow. The narrowed arteries make it harder for blood to get to the heart muscle. Less blood means a lower oxygen supply, and the lack of oxygen causes stress to the heart muscle cells and, in turn, pain.
Other causes of angina include:
- Inflammation of the arteries or spasm of the arteries.
- Some conditions, including a rapid heartbeat). and hyperthyroidism, increase the amount of oxygen required by the heart and the blood supply cannot keep pace with the demand for oxygen.
- Conditions such as anaemia, respiratory conditions and blood loss reduce the capacity of the blood to carry oxygen.
Risk factors for angina include:
In stable angina, there is a known trigger which responds to treatment. The trigger is usually physical exertion. The chest pain generally settles once the physical activity has stopped.
In unstable angina, the chest pain attacks are unpredictable and can happen at rest, rather than with exertion. The causes of the attacks are not obvious, and the attacks may not respond to the treatments used for stable angina. This usually happens in older people, and indicates a high risk of heart attack.
Unstable angina is a medical emergency that requires prompt treatment to prevent further damage to the heart.
Variant (or Prinzmetal) angina is a rare type of angina that usually occurs in younger people. In variant angina, there are recurring episodes of angina at rest, particularly during the morning hours, which result from spasm of the coronary arteries. These exact cause of the spasm is not always clear. However, recreational drugs can occasionally be a cause.
Signs and symptoms
Signs and symptoms of angina include:
- A feeling of pressure, tightness, pain or discomfort in the chest;
- Breathlessness and sweating, and;
- Pain radiating to the neck, jaw, or arms and sometimes the back and shoulders.
Methods for diagnosis
Your doctor will take your full medical history, focusing on the characteristics of your pain, associated symptoms and risk factors for heart disease. They will also ask questions that will help exclude other causes of chest pain.
Your doctor will examine you by taking your heart rate, breathing rate and blood pressure, and by listening to your heart and lungs with a stethoscope.
Heartbeats are caused by coordinated electrical currents through the heart's cells. During ECG, electrodes are attached to your chest while you lie on your back. The electrodes record your heart's electrical activity. The results can often show your doctor whether your heart muscle is damaged or under strain.
Your ECG may show a normal rhythm, particularly if you are not experiencing angina during the test. If an ECG is done while you experience pain, it may show changes that should return to normal once the pain resolves.
If your doctor is concerned that you might be having a heart attack, they may perform a blood test for troponin. This is a substance found in heart muscle cells. If heart muscle cells are damaged, troponin can spill out to the blood, and so troponin levels in the blood can be higher than normal. If you have angina, troponin levels will be normal, because heart cells should not be damaged.
Exercise ECG stress test
Because stable angina usually occurs during exertion, stress testing may be performed to help with diagnosis. ECG leads are attached to your chest while you walk or run on a treadmill. The ECG can show changes of angina with increased levels of exertion and help match these changes to your symptoms.
Non-exercise stress test
Other types of stress tests can involve using an echocardiogram (heart ultrasound) or a nuclear scan to find the areas of the heart that are not receiving enough oxygen. These tests usually use a medication (rather than exercise) to increase the stress on the heart, because they are too hard to perform while you are moving. They may also be chosen instead of an exercise stress test if you cannot move well due to injury or poor physical fitness.
Coronary angiography can detect the site and severity of coronary artery disease. A substance called a 'contrast agent' is injected into your bloodstream. The contrast agent shows up well on X-ray and/or CT images. These images can thus give your doctor a detailed picture of your blood vessels, making it easier to detect any blockages or narrowing.
Holter monitors record your heart's rhythm and rate over a 24-hour period. The monitor is a small device with electrodes that are placed on your chest. This may help in diagnosing angina that is occurring at rest or angina caused by abnormal rhythms of the heart.
Screening blood tests
Blood tests that measure the levels of blood cholesterol and glucose can give your doctor important information needed to manage your risk of heart problems.
Types of treatment
GTN works by dilating (widening) coronary blood vessels, making it easier for blood to get to the heart. GTN tablets are placed under the tongue and allowed to dissolve. GTN is also available in a spray which is also used under the tongue. GTN patches can be applied to the skin to help prevent episodes of angina.
Depending on your circumstances, you may be given beta-blockers and calcium channel blockers. These medications can help lower blood pressure.
You may be given other medications to thin the blood (such as aspirin or warfarin), or to control risk factors such as blood pressure, high cholesterol or diabetes.
Stents can be inserted during coronary angiography to ensure that the blood vessels remain clear. If you have stents, you may need long-term use of blood-thinning medications, such as aspirin and warfarin.
Coronary artery surgery
If an obstruction in your coronary artery cannot be stented, you may have to have coronary artery surgery. There are several different ways to perform this surgery, depending on the nature of your blood vessel obstruction.
Coronary artery surgery is a major surgery and is usually performed on people at high risk of heart attack from coronary artery disease.
If angina and its relevant risk factors are left untreated, it increases your risk of heart attack.
If you are experiencing chest pain that is lasting longer than your usual angina, or it is not responding to your usual treatment, call an ambulance immediately.
Treatment side effects
Side effects of nitrates such as GTN include headache, dizziness, low blood pressure, flushing and increased heart rate. They can also sometimes worsen angina rather than relieve it.
Alcohol can also increase the severity of these medications' side effects. Erectile dysfunction medications, such as Viagra®, must not be used at the same time as nitrates, as the side effects are severe and can result in death.
You can also develop a tolerance to GTN, in which case it ceases to be effective. If you are taking nitrates for angina, your doctor will discuss how to avoid this.
Side effects of beta-blockers include breathing issues, impotence, insomnia, fatigue and spasms of blood vessels, which can lead to a worsening of angina. Heart side effects can include heart failure and a slowing of the heart rate. Beta blockers can also interact with calcium channel blockers and other heart medications. These potential risks can be monitored by your doctor, and they will generally only be used if the benefits are thought to outweigh the risks.
Depending on the type of calcium-channel blocker used, side effects of calcium channel blockers include headache, dizziness, constipation and swelling of the ankles and feet.
Your prognosis will improve if you follow the treatment plan as prescribed by your doctor, lose weight (if necessary), control your blood pressure, cholesterol and - if you have it - diabetes, and have regular check-ups with your doctor.
In some of the more serious cases, stenting or cardiac surgery are required, to prevent further angina or heart attack and improve quality of life and life expectancy.
There are several ways you can reduce your risk of developing angina:
- Do not smoke;
- Exercise and eat a healthy diet to maintain a healthy weight;
- Undergo a risk factor assessment by your doctor and manage these accordingly;
- Avoid stressful situations, and;
- Take your medication as prescribed by your doctor.