Pathophysiology And Etiology Of Angina Biology Essay


Angina is the chest pain or discomfort of cardiac muscle due to the imbalance of myocardial oxygen demand and supply. This condition is normally arisen from coronary artery disease (CAD). Atherosclerosis is the most common CAD which causes angina or chest discomfort. Generally it can be divided into three subtypes such that stable angina, unstable angina and variant angina. Three of these showed different features in the coronary artery and also different symptoms. Beside that, patient with this condition can be diagnosed with several tests like electrocardiogram, stress test and coronary angiography. These tests can confirm whether the patient is suffered from angina. Last but not least, pharmacists should help their patients understand angina well. Other than giving them proper information, medications and advices, pharmacists also play a vital role in improving their lifestyle.

Angina which is commonly known as angina pectoris is a critical crushing pain or discomfort felt in the anterior chest1. The area behind the sternum is the origin of the sensation and it extended across the chest. Normally, heaviness in both arms will be associated, while sometimes, the pain may happens in more uncommon sites when on effort such as jaw or teeth without crushing pain in the chest2. However, the sensation experienced by some other patients is unclear and described as weak pressure like pain and burning sensation. In addition, attack of angina rarely reaches its maximum intensity within seconds as it usually starts slowly then peaked over a period of minutes before disappearing. Resting, sitting or stop walking are preferred by angina sufferers most of the time during attack3.

Types of angina

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Angina can be classified into three main types which are stable angina, unstable angina and variant angina. Firstly, angina which is caused by effort and can be predicted is known as stable angina. For this type of angina, the seriousness will stay constant during the attack2. It is the most usual type of angina suffered by patients. It has to be alleviated by resting, medication and refrain from doing physical activity otherwise it may arise again4.

On the other hand, unstable angina is more serious than stable angina as it will increase in severity. It is induced by exertion as well but it can happen anytime without any prediction. Myocardial infarction may be developed as the result of this angina2. Most of the time patients with unstable angina are having chronic stable angina. The pain in the chest will occur with less and less exertion even at rest5.

Lastly, the rarest kind of angina with the least patients suffered from is called variant angina. Patients with this angina which always associated with coronary spasm often have additional arteriosclerotic lesions. As a result, it can happen during resting time and cannot be predicted2.

Pathophysiology and Etiology

Angina is caused by coronary insufficiency which is the effect of lacking oxygen and nutrients delivery to an organ or cell1. In other words, angina is due to un-match myocardial oxygen need and supply to the heart3.

Most of the time, the need of oxygen in the body is due to the physical activity, exertion, emotion or stress. Under this condition, physiological response which is the rise of hormone noradreanaline that is released by adrenergic nerve ending in the heart and vascular bed will be created. In fact, the pace of carrying out certain activities is the one that determines the level of myocardial oxygen requirements. For example, hurrying an effort involving the motion in any parts of body induces angina.3 Besides this, there are other several factors that causes the requirement of oxygen to rise such as heart rate, ventricular contractility, ventricular wall tension and blood flow.6

Next, based on the evidence shows reduction in myocardial oxygen supply for a very short time also causes angina which is due to coronary vasoconstriction, a condition in which the blood vessel is abnormally narrowed. The conditions may be exacerbated in the presence of vasoconstrictor substances such as serotonin and thromboxane. Other than that, the decrease in vasodilators substances and unusual vasoconstrictor response to exercise due to endothelial damage in artherosclerotic coronary arteries will also causes the insufficient oxygen supply.3

Sign and Symptoms

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The main symptom of angina is the pain and discomfort in the chest. Basically it is characterize as pressure, burning, squeezing and tightness in the chest. Normally the pain is felt in the chest behind the breastbone and then radiate to the left arm, shoulder, throat or jaw.1,8

Moreover, dyspnoea which is also known as shortness of breath often experienced by older people and diabetes patients. Sometimes the signs and symptoms of angina may not be distinguished in elderly people as the manifestation are disguised by fatigue, light-headedness and confusion.1,8

Besides that, symptoms such as nausea, a sensation of unease of sick in the stomach, sweating and dizziness may occurs.8 Fatigue or tiredness have to be suspected to be a sign of angina if it happens unusually early during exercise and back to normal rapidly at rest.1

All and all, the signs and symptoms of the angina may be different based on the type of angina the patients have. The chest pain has to be concerned all the time as there are so many possible symptoms and causes of angina.1,8

Impact of Angina

For patients who suffer from angina have to make changes in their lifestyle. Exertions such as physical activity at work or home have to be reduced. A change of job is required for those who are airplanes pilots, miners and other jobs that stress the heart. Carrying heavy things like luggage also must be refrained.2

Furthermore, intensive and competitive sports such as squash, rugby, and badminton must be stopped as it involves in physical exertion and emotional factors.

However, regular daily exercise which is steady and not vigorous such as swimming or yoga is recommended.2

Additionally, well balanced diet which is low in sodium, cholesterol has to be taken. Certain diets are best to prevent certain cardiovascular diseases (CVD). For example low sodium diet is to prevent heart failure and hypertension while low cholesterol diet is to prevent stroke and coronary artery disease (CAD).9 Low cholesterol diet can be achieved by cutting down fatty foods such as fast food and increase the intake of oats. The weight must also be reduced to normal level and also need to be maintained. Smoking must be stopped before CVD developed. 10

Test and Diagnosis

Usually patients are first diagnosed with physical examination by the doctor and by asking the symptoms that the patients experienced. Further confirmation will be made to identify angina by using tests such as electrocardiogram (EKG), stress test and coronary angiography.11

EKG is a painless test that detects and records the heart's electrical activity which the detections come from the electrical impulses generated from the heart. The patterns of the heartbeats will show the condition of the artery such that whether the blood flow has been blocked or slowed down. These result obtained are the evidence of heart damage due to coronary heart disease (CHD) and sign of previous or current heart attack. 11,12

Next, stress test is a test where patients have to do exercise such as walking on a treadmill or pedalling a stationary bicycle as angina is easier to be identified when the heart is working harder.11 Through out the exercise the blood pressure and the EKG reading are being noted which will show the possible symptoms of CHD. These include abnormal changes in heart rate, blood pressure or heart rhythm and also shortness of breath or chest pain.11,12

Lastly, coronary angiography is done by injecting a dye into the heart's blood vessels so that the inside of the arteries can be examined through X-ray imaging. A procedure known as cardiac catheterization is carried out in the test to get the dye into the blood vessels. By undergoing this test, the blockage of coronary arteries due to artherosclerotic plaque can be visualized through a series of images taken by X-ray machine with more detailed look at inside of arteries.5,11,12


Angina attacks can be prevented by several drugs or pharmacologic agents. These agents are used to reduce the myocardial oxygen needs by decreasing the cardiac workload. Generally, there are three classes of medications such as the organic nitrates, B-blockers and calcium antagonists involved in the treatment.5

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Firstly organic nitrates are one of the oldest treatments for angina which can relieve chest pain primarily through vasodilatation, particularly in systemic veins. The mechanism begins at or near the plasma membrane of vascular smooth muscle cells where the administered drug is converted to nitric oxide. The converted nitric oxide will then activate guanylate cyclise to produce cyclic GMP. As the cyclic GMP builds up, the smooth muscle will relax. Besides that, one of the most commonly used organic nitrates known as nitroglycerin will produce greater dilation of veins then arterioles at low dose. Due to venodilation, blood will accumulate in the veins, reduces the flow back of blood to the heart and thus decrease right and left ventricular filling. Because of this the cardiac output may fall and pressure stretching the ventricle will be reduced. As a result, myocardial oxygen consumption will be lowered and the oxygen imbalance in the state where the blood is restricted will be counteracted.5

On the other hand, B- blockers such as propanolol, esmolol and metoprolol will produce antianginal effect by reducing myocardial oxygen need. B-blockers act towards B-receptor which can be divided into two classes which are B1 and B2 adrenergic receptor. B1 adrenergic receptors can be found in myocardium while B2 adrenergic receptors are located through out peripheral blood vessels. Basically, B-blockers are able to reduce the heart rate, blood pressure and contractility of the heart. Other than suppressing chronic angina, studies have shown that they decrease the frequency of recurrent infarction and mortality following an acute myocardial infarction.5

Lastly calcium antagonists are known as vasodilation drugs. One of the major groups of calcium antagonist is called dihydropyridines including nifedipine, nitrendipine and felodipine. They antagonize voltage-gated L-type calcium channels located in the vascular smooth muscle and cardiac muscle. However the actions of individual drugs will act differently at different part such that some are more active on blood vessels while some are more active on the heart.5,13 Dihydropyridines are the most potent vasodilators among the others. One of the two effects cause by this vasodilator is that it decreases oxygen demand through venodilation and arterial dilatation which reduces ventricular filing, size and also the resistance exerted against the left ventrical of the heart during contractions respectively. Another effect is that it increases the myocardial oxygen supply through coronary dilatation. Coronary artery spasm can also be managed because of the latter effect that calcium antagonist give.5

Clinical scenario 1

A 52 year old man has been presented to his doctor with a chest pain on exertion, which has occurred over the previous two weeks. He is diagnosed with angina. He received the following prescription

Aspirin 75mg One tablet in the morning

Atenolol 100mg One tablet in the morning

GTN spray One dose as required for chest pain

Aspirin which is an antiplatelet drug is used to treat CAD. It inhibits platelets aggregation which will then leads to the reduction in subsequent release of platelet-derived procoagulants and vasoconstrictors.5 In this case the 52 year old male patient has to take one tablet of 75mg aspirin in the morning which can prevent further cardiovascular disease events in long term effect.14 By taking 75mg of aspirin per day the risk of heart attack can be reduced. This small dosage of aspirin is sufficient to avoid the blood flowing through the coronary arteries from clotting and thus preventing the blockage of the arteries.15 Pharmacist should teach the patient regarding the administration and precautions of the drug. For this patient, he has to take this drug by mouth and with a glass of water. It must be swallowed as a whole in enteric-coated form without chewing it otherwise the risk of side effects may increase. He should have food or milk taken along with this medication if stomach upset happens.16 Furthermore, a pharmacist must give special precaution such that he must not take ibuprofen otherwise aspirin will not work effectively. Alcohol beverages and smoking must be stop or limit to control and reduce the side effect of aspirin.15,16 Besides that, possible side effects for this drug have to be mentioned by pharmacist to the patient such as stomach inflammation, gastrointestinal bleeding and allergic reaction. If any of these happens, pharmacist must ask the patient to seek for immediate medical attention to prevent further serious effect. Heartburn may also be experienced by the patient. Instead of taking oral aspirin, pharmacist is responsible to give better drug such as coated aspirin or alternative like antacid for the patient whoever experience heartburn.15,16

Atenolol is one the most water soluble beta-blockers. Pharmacist should always tell the patient that the main point for taking the drug which is to treat chest pain and high blood pressure and if necessary simple explanation regarding the action of the drug must be given.14 By taking this drug the heart rate and strain on the heart will be lowered, as the drug works by blocking the action of certain chemical in the body like epinephrine on the heart and blood vessels. As a pharmacist, ensuring the patient to keep his medication on track is very important as his condition may be exacerbated if he suddenly stops taking it. Moreover, pharmacist needs to remind him to take this drug regularly on time so that he will not forget and get the benefits from it. The ineffectiveness to take this drug when chest pain occurs must be mentioned by pharmacist. There are some side effects which he may experience which include dizziness, diarrhea and nausea. This may be due to the adaptation of the body towards the drug. Cold sensation should be expected as this drug will reduce the blood flow to the hands and feet. In this case, pharmacist need to give appropriate suggestion to the patient like dress warmly and refrain from smoking as tobacco use can make the condition worse. If serious side effects which are unlikely to occur such as slow heartbeat and numbness in the hand and feet happen, pharmacist should ask the patient to seek for doctor immediately.17

GTN spray is also known as lingual glyceryl trinitrate which is one of the most effective nitrates drug to treat angina as it provides rapid indicative relief. This fast acting drug will have its maximal action occurring within three minutes as it is absorbed into the bloodstream through the oral mucosa very quickly.5,14 It relieves the chest pain by relaxing and dilating the blood vessels so that the blood can flow smoothly and more easily to the heart. Before using this medication, method of administration and warnings must be given by a pharmacist. He has to hold the container firmly with the index finger on the grooved button, bring it near to his mouth and spray the medication under the tongue once in sitting position. After that he needs to close his mouth without swallowing or inhaling the spray. Eating, splitting and rinsing the mouth are not allowed for 5 to 10 minutes, so that the medicine is absorbed under the tongue into the bloodstream. If the pain still persists or worsened 5 minutes after spraying the medication, he must call emergency medical help. Pharmacist must tell him the maximum dosage he can only take which is three times during an attack. Headache is usually experienced by patients who take this drug which indicates that the medication is working. For this patient, he should not worry as the low dose aspirin he is taking can counter alleviates the headache. Last but not least, pharmacist should ask him to take note some of the allergic symptoms and side effects such as rashes, itchiness and severe dizziness.18

Clinical scenario 2

A 79 year old lady with a history of congestive heart failure and angina receives the following prescription:

Aspirin 75mg One tablet in the morning

Imdur 60mg One tablet in the morning

GTN tablets 500mcg One tablet as required for chest pain

A pharmacist must influence a patient's compliance with a drug treatment regimen. In order to achieve that, pharmacist should be responsible and competent enough to dispense drugs safely by checking the correct labels and dosage. It is also very important for a pharmacist to educate the patient route of administration of particular drugs, special warnings and proper storage. For this patient, she needs to take aspirin in tablet form that released the medication slowly over some time once a day to reduce the risk of angina attack or stroke. She must not chew this drug but swallow it as a whole with a full glass of water. Besides that, Ibuprofen which is used to treat fever or pain must not be taken to prevent any interactions of drugs. In case she misses a dose in the morning, she has to take the medication once she remembered on that day. The dose can only be skipped when the time for next dose in the next morning is near. On the other hand, she may also experience some side effects which can be serious like vomiting, nausea, stomach pain and heartburn. In that case, she should call the doctor for help and advice. Other than being cautious towards the side effects, the storage of the drug must not be ignored. The medication must be kept in the container that it came in and tightly closed. It has to be stored in room temperature and avoid the exposure of excessive heat and moisture. Any outdated tablets must not be consumed no matter how good they are stored but to be disposed. Lastly, she must asked from pharmacists for drug refill with the prescription together.19

Imdur which is known as isosorbide mononitrate belongs to a nitrate group. This medication is very appropriate for this patient as it can prevent angina attack in patient which has congestive heart failure. It works generally the same as other nitrate drugs such that widening and relaxing the blood vessels to allow the blood flow smoothly to the heart.20 Just like aspirin, imdur is an extended-release tablet which is only needed once a day. The administration of imdur is almost the same as aspirin. This patient should refrain from chewing the tablet but swallow it as a whole with half a glass of water. She must take this drug with an empty stomach at least 1 or 2 hours before the meal. The main purpose of this medication is to control chest pain instead of curing it. She must take correct dosage prescript by the doctor without stopping it even when she is feeling well. Other than preventing angina attack, this medication is also used to treat congestive heart failure. The missing dose should also be ignored if it is almost time for the next dose otherwise it must be taken as soon as she remembered it. She may also experience some adverse effects including headache, stomach upset and chest pain. If that is the case she must let her doctor know immediately. Basically, this drug is stored just like the aspirin. Any exposure of excess heat and moisture must be prevented. She should only open the container when she needs to take the medication. Tablets that have outdated or more than 12 months must be thrown and should not be consumed. 21

Nitroglycerin which comes in sublingual is known as GTN tablets. These tablets are used to treat episodes of angina or chest pain and they are taken as needed which is either 5 to 10 minutes before physical activity that may cause angina or when the pain is felt in the chest. Other than educate the patient with drug knowledge, pharmacist have to let the patient understand that the medication she is taking is to control and prevent angina but not cured. Based on this patient's case, she must take the correct dose without changing the amount when angina attacks. She must put the tablet under her tongue without breaking it in sitting position. It will be normal for her to feel burning and tingling in the mouth as the tablet dissolves which indicates that the drug is working fine. However, she should not concern too much if this is not the case. Generally, 3 tablets are the maximum amount that can be taken to relieve chest pain. If the first dose is enough to treat the pain, second dose is unnecessary; otherwise she can take second tablet 5 minutes after the first tablet. Emergency call must be made if the pain persists after 3 doses are taken. There are some side effects cause by this tablet such as flushing, dizziness and light-headed. She also needs to tell her doctor if she experience any other symptoms which are unknown.2


In conclusion, angina is one of the most common disorder suffer from patients with coronary artery disease. Many people have misunderstood it as a heart attack. In fact, chest pain is just one of the major symptoms associated to angina. It can leads to chronic heart disease if the condition is not treated and manage well. Death may happen if angina is neglected or proper treatment or medication is not given. To achieve this, it definitely requires special attention from healthcares providers such as doctors and pharmacists. Pharmacists should be able to identify self-medicating angina patients and help them to relieve the associated symptoms with the over-the-counter medications. Any drugs refilling and information about drugs must get from the pharmacists. However, if patients experience any adverse effects or unknown symptoms, they are advised to seek consultation with doctors.