Angina: Symptoms, Causes, Diagnosis and Treatment

Angina: Symptoms, Causes, Diagnosis and Treatment

What Is Unstable Angina?

Angina is a condition marked by crushing pain in your chest that may also be felt in your shoulders, neck, and arms. The pain is caused by inadequate blood supply to your heart, which leaves your heart deprived of oxygen.
Angina: Symptoms, Causes, Diagnosis and Treatment
There are several types of angina; stable angina occurs when you are exerting yourself physically or feeling considerable stress. Stable angina does not typically occur more frequently or worsen over time.
Unstable angina is chest pain that happens suddenly and becomes worse over time. It occurs seemingly without cause—you may be at rest or even asleep. An attack of unstable angina may lead to a heart attack. For this reason, an attack of unstable angina should be treated as an emergency, and you should seek immediate medical treatment.

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What are the symptoms of angina?

The main symptom of angina is chest discomfort/pain, but this sensation can vary from person to person. Sometimes unstable angina causes sensations that feel as if you are having a heart attack.
Angina: Symptoms, Causes, Diagnosis and Treatment

Angina symptoms include:
  • squeezing or sharp chest pains
  • pain that radiates to extremities and/or back
  • nausea
  • anxiety
  • sweating
  • shortness of breath
  • dizziness
  • unexplained fatigue

Typical and common angina symptoms

The common symptom is a pain, ache, discomfort or tightness that you feel across the front of the chest when you exert yourself. For example, when you walk up a hill or against a strong, cold wind. You may also, or just, feel the pain in your arms, jaw, neck or stomach. 

An angina pain does not usually last long. It will usually ease within 10 minutes when you rest. If you take some glyceryl trinitrate (GTN) - it should go within 1-2 minutes (see 'Glyceryl trinitrate' section, below). 

Angina pain may also be triggered by other causes of a faster heart rate. For example, when you have a vivid dream or an argument. The pains also tend to develop more easily after meals.

Less typical symptoms that sometimes occur

Some people have nontypical pains - for example, pains that develop when bending or eating. If the symptoms are not typical then it is sometimes difficult to tell the difference between angina and other causes of chest pain, such as a pulled muscle in the chest or heartburn. 

Some people with angina also become breathless when they exert themselves. Occasionally, this is the only symptom and there is no pain.

What Causes the Condition?

Coronary heart disease caused by a buildup of plaque (fatty deposits) along the walls of your arteries (atherosclerosis) is the principal cause of unstable angina. The plaque causes your arteries to narrow and become rigid. That constricts blood flow to your heart. When the heart is deprived of blood and oxygen, you will feel chest pain.
Angina: Symptoms, Causes, Diagnosis and Treatment

Risk factors for coronary heart disease include:

  • diabetes
  • obesity
  • family history of heart disease
  • high blood pressure
  • high LDL cholesterol
  • low HDL cholesterol
  • being male
  • using any form of tobacco
  • leading a sedentary life
Men 45 and older and women 55 and older are more likely to experience unstable angina.

How is angina diagnosed?

Usually the doctor can diagnose angina by noting the symptoms and how they arise. However one or more diagnostic tests may be needed to exclude angina or to establish the severity of the underlying coronary disease. These include the electrocardiogram (ECG) at rest, the stress test, and x- rays of the coronary arteries (coronary "arteriogram" or "angiogram"). 

The ECG records electrical impulses of the heart. These may indicate that the heart muscle is not getting as much oxygen as it needs ("ischemia"); they may also indicate abnormalities in heart rhythm or some of the other possible abnormal features of the heart. To record the ECG, a technician positions a number of small contacts on the patient's arms, legs, and across the chest to connect them to an ECG machine. 

For many patients with angina, the ECG at rest is normal. This is not surprising because the symptoms of angina occur during stress. Therefore, the functioning of the heart may be tested under stress, typically exercise. In the simplest stress test, the ECG is taken before, during, and after exercise to look for stress related abnormalities. Blood pressure is also measured during the stress test and symptoms are noted. 

A more complex stress test involves picturing the blood flow pattern in the heart muscle during peak exercise and after rest. A tiny amount of a radioisotope, usually thallium, is injected into a vein at peak exercise and is taken up by normal heart muscle. A radioactivity detector and computer record the pattern of radioactivity distribution to various parts of the heart muscle. Regional differences in radioisotope concentration and in the rates at which the radioisotopes disappear are measures of unequal blood flow due to coronary artery narrowing, or due to failure of uptake in scarred heart muscle. 

The most accurate way to assess the presence and severity of coronary disease is a coronary angiogram, an x-ray of the coronary artery. A long thin flexible tube (a "catheter") is threaded into an artery in the groin or forearm and advanced through the arterial system into one of the two major coronary arteries. A fluid that blocks x-rays (a "contrast medium" or "dye") is injected. X-rays of its distribution show the coronary arteries and their narrowing.

Treatment for Angina

The underlying coronary artery disease that causes angina should be attacked by controlling existing "risk factors." These include high blood pressure, cigarette smoking, high blood cholesterol levels, and excess weight. If the doctor has prescribed a drug to lower blood pressure, it should be taken as directed. Advice is available on how to eat to control weight, blood cholesterol levels, and blood pressure. A physician can also help patients to stop smoking. Taking these steps reduces the likelihood that coronary artery disease will lead to a heart attack. 

Most people with angina learn to adjust their lives to minimize episodes of angina, by taking sensible precautions and using medications if necessary. 

Usually the first line of defense involves changing one's living habits to avoid bringing on attacks of angina. Controlling physical activity, adopting good eating habits, moderating alcohol consumption, and not smoking are some of the precautions that can help patients live more comfortably and with less angina. For example, if angina comes on with strenuous exercise, exercise a little less strenuously, but do exercise. If angina occurs after heavy meals, avoid large meals and rich foods that leave one feeling stuffed. Controlling weight, reducing the amount of fat in the diet, and avoiding emotional upsets may also help. 

Angina is often controlled by drugs. The most commonly prescribed drug for angina is nitroglycerin, which relieves pain by widening blood vessels. This allows more blood to flow to the heart muscle and also decreases the work load of the heart. Nitroglycerin is taken when discomfort occurs or is expected. Doctors frequently prescribe other drugs, to be taken regularly, that reduce the heart's workload. Beta blockers slow the heart rate and lessen the force of the heart muscle contraction. Calcium channel blockers are also effective in reducing the frequency and severity of angina attacks. 

If you have a blockage or severe narrowing in an artery, your physician may recommend more invasive procedures. These include angioplasty, where a physician opens up an artery that was previously blocked. Your physician also may insert a small tube known as a stent to keep your artery open.

In severe instances, you may require heart bypass surgery, which reroutes blood flow away from a blocked artery to help improve blood flow to your heart.

Nonmedical treatment options also are often recommended. These include taking steps to lose weight, giving up tobacco use, or exercising more regularly. Taking steps toward a healthier lifestyle can improve your heart health and reduce the risk for future unstable angina episodes.

Other treatments that are advised in most cases

Lifestyle measures to reduce risk factors

Glyceryl trinitrate (GTN)

This medicine comes as tablets or sprays. You take a dose under your tongue as required when your angina pain develops. GTN is absorbed quickly into the bloodstream, from under the tongue. A dose works to ease the pain within a minute or so. 

You should always carry your GTN spray or tablets with you. Some people take a GTN tablet or a spray before any exercise - for example, before climbing stairs. If the first dose does not work, take a second dose after five minutes. If the pain persists for 10 minutes despite taking GTN, then call an ambulance. 

GTN works by relaxing the blood vessels. This reduces the workload on the heart, and also helps to widen the coronary arteries and increase the flow of blood to the heart muscle.

GTN tablets go off after a few weeks, so you need a fresh supply every eight weeks and should return any unused tablets to the pharmacist. You may prefer to use a GTN spray which has a longer shelf life than tablets. 

A dose of GTN may cause a headache and/or flushing for a short while. This side-effect often improves, or goes, with continued use.

A statin medicine to lower your cholesterol level

Cholesterol is a chemical that is made in the liver from fatty foods that you eat. Cholesterol is involved in forming atheroma. As a rule, the higher the blood cholesterol level, the greater the risk of developing atheroma. However, whatever your cholesterol level, a reduction in the level is usually advised if you have angina. 

Statin medicines lower the blood cholesterol level by blocking an enzyme which is needed to make cholesterol in the liver. There are several different statin medicines to choose from.

Aspirin or another antiplatelet medicine

Aspirin reduces the stickiness of platelets. Platelets are tiny particles in the blood that help the blood to clot after cuts. If lots of platelets become stuck on to a patch of atheroma inside an artery they can form a clot (thrombosis). Therefore, taking aspirin reduces the risk of a heart attack, which is caused by a blood clot forming in a coronary artery. 

The usual dose of aspirin is 75 mg daily. This is a much smaller dose than that used for pains and headaches. Side-effects are unusual with low-dose aspirin. If you have a stomach or duodenal ulcer, or asthma, you may not be able to take aspirin. Options then include taking an additional medicine to protect the gut, or using another antiplatelet medicine such as clopidogrel. See leaflet called 'Aspirin and Other Antiplatelet Medicines' for details.

A beta-blocker medicine

Beta-blockers block the action of certain hormones such as adrenaline, which increase the rate and force of the heartbeat when you exert yourself or are anxious. Therefore, when taking a beta-blocker, less oxygen is needed by the heart and angina pains are prevented, or occur less often. 

Beta-blockers are also thought to have some protective effect on the heart muscle, which may reduce the risk of developing complications.

An angiotensin-converting enzyme (ACE) inhibitor medicine

There are several types and brands of ACE inhibitors. These medicines prevent a build-up of fluid by interfering with the enzyme angiotensin which is involved in regulating body fluid. ACE inhibitors also have a protective effect on the heart and may slow down the progression of heart failure. 

An ACE inhibitor is usually prescribed to people with angina who are shown to have a reduced function of the left ventricle of the heart or who have had a heart attack (myocardial infarction). In these situations there is good evidence that an ACE inhibitor improves the outlook. However, it is uncertain whether an ACE inhibitor should be taken routinely by people with angina who do not have these other heart problems. It is hoped that research will clarify this issue. In the meantime, some doctors do prescribe an ACE inhibitor to all their patients with angina.

What if medication fails to control angina?

Doctors may recommend surgery or angioplasty if drugs fail to ease angina or if the risk of heart attack is high. Coronary artery bypass surgery is an operation in which a blood vessel is grafted onto the blocked artery to bypass the blocked or diseased section so that blood can get to the heart muscle. An artery from inside the chest (an "internal mammary" graft) or long vein from the leg (a "saphenous vein" graft) may be used. 

Balloon angioplasty involves inserting a catheter with a tiny balloon at the end into a forearm or groin artery. The balloon is inflated briefly to open the vessel in places where the artery is narrowed. Other catheter techniques are also being developed for opening narrowed coronary arteries, including laser and mechanical devices applied by means of catheters.

Can a person with angina exercise?

Yes. It is important to work with the doctor to develop an exercise plan. Exercise may increase the level of pain-free activity, relieve stress, improve the heart's blood supply, and help control weight. A person with angina should start an exercise program only with the doctor's advice. Many doctors tell angina patients to gradually build up their fitness level--for example, start with a 5-minute walk and increase over weeks or months to 30 minutes or 1 hour. The idea is to gradually increase stamina by working at a steady pace, but avoiding sudden bursts of effort.

What is the difference between "stable" and "unstable" angina?

Angina: Symptoms, Causes, Diagnosis and Treatment
It is important to distinguish between the typical stable pattern of angina and "unstable" angina. 

Angina pectoris often recurs in a regular or characteristic pattern. Commonly a person recognizes that he or she is having angina only after several episodes have occurred, and a pattern has evolved. The level of activity or stress that provokes the angina is somewhat predictable, and the pattern changes only slowly. This is "stable" angina, the most common variety. 

Instead of appearing gradually, angina may first appear as a very severe episode or as frequently recurring bouts of angina. Or, an established stable pattern of angina may change sharply; it may by provoked by far less exercise than in the past, or it may appear at rest. Angina in these forms is referred to as "unstable angina" and needs prompt medical attention. 

The term "unstable angina" is also used when symptoms suggest a heart attack but hospital tests do not support that diagnosis. For example, a patient may have typical but prolonged chest pain and poor response to rest and medication, but there is no evidence of heart muscle damage either on the electrocardiogram or in blood enzyme tests.