Myocardial Infarction or Heart Attack

The Coronary arteries
The Coronary arteries

Myocardial Infarction(MI) or Heart Attack

what is a myocardial infarction?

A myocardial infarction(MI) or heart attack is the death(infarct) of a portion of heart muscle due to sudden loss of blood supply.

Heart and coronary arteries.

The heart has four major arteries. Blood is pumped out through the largest of these arteries, the aorta, which circulates it through the body. The pulmonary artery supplies blood to the lungs. The right and left coronary arteries bring oxygen rich blood to the heart itself.

Like any other muscle, the heart muscle needs a good blood supply.The coronary arteries take blood to the heart muscle. The main coronary arteries branch off from the aorta.The main coronary arteries divide into smaller branches which takes blood to all parts of the heart muscle.


Causes of myocardial infarction.

The most common cause is atherosclerosis ("hardening of the arteries"), a build-up of fatty deposits called plaque. Over time, plaque clogs and narrows the arteries and other blood vessels, and slows or blocks the flow of blood to the heart and elsewhere. Sometimes, the surface of plaques can rupture or tear, which can cause blood clots to form that block the arteries. A complete or near-complete blockage of the coronary arteries blocks the blood flow to a part of the heart which results in MI.

Other causes:Various other uncommon conditions can block a coronary artery and cause an MI. For example: inflammation of the coronary arteries (rare); a stab wound to the heart; a blood clot forming elsewhere in the body (for example, in a heart chamber) and travelling to a coronary artery where it gets stuck; cocaine abuse which can cause a coronary artery to go into spasm; complications from heart surgery; and some other rare heart problems.


Symptoms of myocardial infarction.

Many heart attacks start slowly, usually with a feeling of pain or discomfort in the chest that lasts more than a few minutes, or goes away and returns. Pain from an MI generally lasts for more than 30 minutes, and may continue for several hours. The longer the pain lasts, the greater the risk of muscle damages.Chest pain due to a reduced blood supply to the heart is called angina.(Angina usually goes off after a few minutes. MI pain usually lasts more than 15 minutes - sometimes several hours.)

People may feel different symptoms during a heart attack or MI - and some people feel no unusual symptoms.Usually described symptoms are;

An intense pain in the left side or center of the chest. The pain may also travel up into the neck, back, arms or jaw.A feeling of extreme pressure, fullness, or tightness in the chest. Nausea, dizziness, weakness, shortness of breath, or a cold sweat also can be experienced.

Not everyone experiences acute chest pain and some may have a combination of symptoms. Other MI survivors report a vague feeling that their heart or health is "not quite right." There may be only a slight discomfort. About one-quarter of all heart attacks occur without producing any noticeable warning signs. These "silent" heart attacks may go undiscovered until they show up during routine heart tests such as an electrocardiogram (ECG).

How serious is a myocardial infarction.

An MI is potentially very serious. It can lead to a chronic disabling condition because it can cause heart failure, or it can lead to full recovery. In some, it is rapidly fatal mainly because if the heart’s rhythm is disturbed, permanent brain damage and death can occur unless blood flow is quickly resumed.In many cases only a small part of the heart muscle is damaged (infarcts or dies) which heals as a small patch of scar tissue. The heart can usually function normally with a small patch of scar tissue. A larger MI is more likely to be life-threatening or cause complications.

How is myocardial infarction treated.

Medical treatment is aimed to open the blocked artery and restore blood flow to the affected area of heart muscle (doctors call this reperfusion). Treatment is also aimed at preventing further damage and the chance of repeat heart attacks in the future.

The part of the heart muscle starved of blood does not die ('infarct') immediately. If blood flow is restored within a few hours, much of the heart muscle that would have been damaged will survive. This is why an MI is a medical emergency, and treatment is given urgently. The quicker the blood flow is restored, the better the outlook. There are two treatments that can be done to restore blood flow back through the blocked artery.

Emergency angioplasty is, ideally, the best treatment if it is available and can be done within a few hours of symptoms starting. In this procedure a tiny wire with a balloon at the end is put into a large artery in the groin or arm. It is then passed up to the heart and into the blocked section of a coronary artery using special x-ray guidance. The balloon is blown up inside the blocked part of the artery to open it wide again. A stent may be left in the widened section of the artery. A stent is like a wire mesh tube which gives support to the artery and helps to keep the artery widened.

An injection of a 'clot busting' drug is an alternative to emergency angioplasty. In reality, this is the more common treatment as it can be given easily and quickly in most situations. Commonly used drug is streptokinase.

Once the artery is open, the heart attack is generally halted and the patient becomes pain free.

The patient is most likely to make a good recovery if reperfusion can be established in the first 4-6 hours of a heart attack.

Anti-platelet medicines, for example aspirin, reduce the tendency of platelets (a type of blood cell) in the blood to clump and clot. These medicines help to prevent the arteries from becoming blocked again.

Nitroglycerin, a vasodilator (blood vessel dilator), widens the blood vessel by relaxing the muscular wall of the blood vessel.

ACE (angiotensin converting enzyme) inhibitors, another type of vasodilator, improve the heart muscle healing process. They do this by blocking the production of a hormone (chemical signal carried in the blood) called angiotensin II.

Beta-blocking agents interfere with the nerves controlling the heart by blocking the action of a chemical they release called noradrenaline. They also block a hormone (chemical carried in the blood) called adrenaline. This makes the heart beat more slowly and less forcibly, which decreases the amount of muscle damage and can help to prevent serious arrhythmias.

A statin drug to lower the cholesterol level in your blood.

After having a myocardial infarction.

After recovering from an MI, it is natural to wonder if there are any 'dos and don'ts'. In the past, well-meaning but bad advice to "rest and take it easy from now on" caused some people to become over-anxious about their hearts. Some people gave up their jobs, hobbies, and any activity that caused exertion for fear of 'straining the heart'. However, quite the opposite is true for most people who recover from an MI. Regular exercise and getting back to normal work and life is usually advised.

How to prevent myocardial infarction.

Everybody has a risk of developing atherosclerosis which can lead to an MI. However, certain 'risk factors' increase the risk and include:

Preventable or treatable risk factors: Smoking, hypertension, poor diet, lack of exercise, high cholesterol level, obesity, excess alcohol.

Having diabetes. But if you have diabetes, the increased risk of heart disease is minimised by good control of the blood sugar level, and reducing blood pressure if it is high.

Briefly, if you can reduce any risk factors, it reduces your risk of having an MI (or of having a further MI if you have already had one).

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Comments 20 comments

gopi 2 years ago

good to see something useful for our health after a long search. I appreciate your effort of making this page. I love writing too. Please recommend me some useful tips to be a good writer.


Vinaya Ghimire profile image

Vinaya Ghimire 4 years ago from Nepal

Useful and informative. Thanks for sharing.


dinkan53 profile image

dinkan53 4 years ago from India Author

@sweetie2 You are absolutely right, smoking, both active and passive is extremely dangerous to health. Appreciate your visit and feedback, thanks.


sweetie2 profile image

sweetie2 4 years ago from Delhi

Very informative hub and smoking not only cause cancer as many people think but also cause many more diseases too.


dinkan53 profile image

dinkan53 4 years ago from India Author

@girishpuri value your comments, thanks for your visit.


girishpuri profile image

girishpuri 4 years ago from NCR , INDIA

Very much useful share about hart problems, generally people does not have the basic knowledge, useful hub, thanks.


dinkan53 profile image

dinkan53 4 years ago from India Author

@KoffeeKlatch Gals MI is really a life changing event. I think you already change your lifestyle and having medicines, most probably for the whole life time. Don't miss your medications and try to have it on the same time every day. Be physically active and get regular medical check-ups. Be positive and god bless you. Thanks for your read, comment and votes.


KoffeeKlatch Gals profile image

KoffeeKlatch Gals 4 years ago from Sunny Florida

Very good advice. I had an infarction about a year ago. I am now on a ton of medicine but I have to say I am living my normal life and feeling fine. Up, and useful.


sandeep 4 years ago

such informative article, we have to protect our heart.


conradofontanilla 5 years ago

You are right. We should be able to discover more about heart disease. I am inspired with what Salk did on the polio bug. He improved upon the killed-virus concept started by Dr. Park and Maurice Brodie and now only a few cases of polio are reported although the bug is still around. I believe if free radicals were dealt with properly, heart disease, arrhythmia, heart failure, stroke, hypertension and other free radical diseases could be prevented, treated and cured. I scorn the fact that heart disease is the top killer in the world; we should be able to lick it. The tools and knowledge are now in our hands. We only have to resist other forces holding us from what should be done. The commercial interests are powerful. I am reminded of what Dr. Samuel Epstein did on occupational health as he wrote in his book "The Politics of Cancer."


dinkan53 profile image

dinkan53 5 years ago from India Author

wow, this is the first time that some one is giving a long comment on my hub. I went through some of your hubs too. We hope for more discovories in heart disease sphere, because it has became one of the leading killer disease. You can make more hubs about heart and heart problems and I think it will be my pleasure to go through those hubs. thank you.


conradofontanilla profile image

conradofontanilla 5 years ago from Philippines

Hi Dinkan53. My ischemia forced me to do literature research to stay on top of it. My first cardiologist was schooled on risk factors so he said I was a candidate for heart surgery. I have found out that risk factors are inadequate in analyzing heart disease that lead to inadequate treatment and cure.It was believed in 1977 by Dr. DeBakey and Dr. Gotto that plague is irreversible and still largely believe it so in 1997 as they wrote in their book "The New Living Heart." However, they said that plaque may be reversed by changes in lifestyle and cholesterol-lowering drug. I am now undergoing infusion chelation therapy and am improving. I have read that stem cell therapy also cures heart disease.This emerging therapy recognizes free radicals as causes of heart disease. Free radicals can be neutralized by antioxidants that provide primary prevention of heart disease. I have Hubs "Heart Disease: Conventional View Versus Free Radical Theories" and "Chelation and Stem Cell Therapies Completely Repair the Heart."


Harry Watson profile image

Harry Watson 6 years ago from Indianapolis, Indiana

Great hub! This confirms for me the depth In which I should write. This is a question I have asked myself so much. Thanks, feel free to critique my first hub. It wasn't ready. I knew it still needed checking. "Publish" was selected by mistake. Harry Watson


pappu 6 years ago

great article. our young generation building up having lot of fast foods should be aware of their health.


Amin Uddin 6 years ago

Your article is very informative i got lot of knowledge thanks


chinnu 6 years ago

what an informative page, more articles like this will make me happy


NADEEM SHAMSI 6 years ago

Good Knowledge provide by you !


ahmadraza212 profile image

ahmadraza212 6 years ago from Pakistan

hi dear very nice information thanks for such type of information


soni2006 profile image

soni2006 7 years ago from New Delhi, India

Thanks dinkan for the latest info on myocardial infarction.


amit luthra profile image

amit luthra 7 years ago from New Delhi, India

thanx for all the information.

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