What Is A Heart Attack? What Causes A Heart Attack?

Editor's Choice
Main Category: Heart Disease
Also Included In: Cardiovascular / Cardiology
Article Date: 27 May 2009 - 3:00 PST

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If the heart muscle does not have enough blood (and consequently oxygen) it dies and a heart attack occurs. Another name for a heart attack is myocardial infarction, cardiac infarction and coronary thrombosis. According to Medilexicon's medical dictionary, a heart attack is "infarction of a segment of heart muscle, usually due to occlusion of a coronary artery". (Infarction = the process whereby an area of dead tissue is caused by a loss of blood supply).

A heart attack usually happens when a blood clot develops in one of the blood vessels that lead to the heart muscle (coronary arteries). The clot, if it is big enough, can stop the supply of blood to the heart. Blood supply to the heart can also be undermined if the artery suddenly narrows, as in a spasm.

What are the symptoms of a heart attack?

• Chest discomfort, mild pain
• Coughing
• Crushing chest pain
• Dizziness
• Dyspnea (shortness of breath)
• Face seems gray
• A feeling of terror that your life is coming to its end
• Feeling really awful (general feeling)
• Nausea
• Restlessness
• The person is clammy and sweaty
• Vomiting

If you experience these symptoms, or witness another person with them, call the emergency services immediately. In the United Kingdom the telephone number is 999, in the USA and Canada it is 911, Australia 000, and New Zealand 111. Many cell phones' emergency number is 112.

A person who is having a heart attack usually feels the pain in his/her chest first. This pain then spreads to the neck, jaw, ears, arms, and wrists. With some patients, the pain also makes its way into the shoulder blades, the back, and the abdomen.

The pain does not feel any better if the patient changes position, rests, or lies down. Often it is a constant pain, but it can come and go. Patients describe the pain as one of pressure, something squeezing. The pain can last from a few minutes to many hours.

People with diabetes, and/or those over the age of 75 may experience a "silent heart attack". This is one that occurs with no pain at all.

Studies indicate that about one fifth of mild heart attacks are not diagnosed. If this is the case, there are many people who are suffering progressive heart muscle damage because it is not being treated.

What are the causes of a heart attack?

• Age - this is considered to be the largest risk factor. When a man is over 45 years, and the woman is over 55 years of age, their risk of having a heart attack starts to rise significantly.


• Angina - angina is an illness where not enough oxygen is reaching the patient's heart. This raises the risk of a heart attack. In some cases a diagnosis of angina was wrong - it could have been a mild heart attack instead. The main difference between a heart attack and angina is that the patient with angina will feel better about 15 to 30 minutes after taking medication, while the heart attack patient won't.


• Blood cholesterol levels - if a person's blood cholesterol levels are high, he/she runs a higher risk of developing blood clots in the arteries. Blood clots can block the supply of blood to the heart muscle, causing a heart attack.


• Diabetes - people with diabetes have a higher risk of developing several diseases and conditions, many of them contribute to a higher risk of heart attack.


• Diet - a person who consumes large quantities of, for example, animal fats, or saturated fats, will eventually have a higher risk of having a heart attack.


• Genes - you can inherit a higher risk of heart attack from your parents, and/or their parents.


• Heart surgery - patients who have had heart surgery have a higher risk of having a heart attack.


• Hypertension (high blood pressure) - this could be due to lack of physical activity, overweight/obesity, diabetes, genes, and some other factors.


• Obesity, overweight - as more and more people are overweight, especially children, experts believe heart attacks will become more common in future (if the overweight children become overweight adults).


• Physical inactivity - people who do not exercise have a much higher risk of having a heart attack, compared to people who exercise regularly.


• Previous heart attack - anybody who has already had a heart attack is more likely to have another one, compared to other people.


• Smoking - people who smoke heavily or regularly run a much higher risk of heart attack, compared to people who never smoked and those who gave up. Smoking regularly means smoking every day.

How is a heart attack diagnosed?

Any doctor, nurse, or health care professional, will send a patient straight to hospital if he/she suspects the person may have a heart attack. In hospital several tests may be done:

• ECG (Electrocardiograph)
  
  An ECG is a medical device that monitors the electrical activity of the heart muscles. Our hearts produce a small electric signal at every beat. A heart specialist (cardiologist) can use this device to see how well the heart is functioning, whether there is any damage to the heart muscle, or abnormalities with the heart rhythm. A doctor can tell, when checking the data coming from the ECG, whether the patient has had a heart attack recently, or even earlier.


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• Cardiac enzyme tests
  
  When a person has a heart attack some enzymes make their way into the bloodstream. A blood test can detect these enzymes. Usually, enzyme blood levels are checked regularly over a few days.


• Chest x-ray
  
  This can be useful to see if the heart has any swelling.

What are the treatments for a heart attack?

The faster the heart attack patient can be treated, the more successful his/her treatment will be. These days, the majority of heart attacks can be treated effectively. It is crucial to remember that the patient's survival depends largely on how quickly he can be taken to hospital.

Treatment during a heart attack

• CPR (cardio-pulmonary resuscitation)
  
  Some heart attack patients stop breathing; they do not move or respond when spoken to or touched, they may also be coughing. If this is the case CPR should be started straight away. This involves:
  
  Manual chest compressions and mouth-to-mouth
  30 chest compressions to the heart
  followed by
  two mouth-to-mouth resuscitation breaths (mouth-to-mouth)
  
  Defibrillator
  This is a CPS medical device. It sends electric shocks across the patient's chest - the aim is to use electricity to shock the heart back into proper activity.


• 300mg of Aspirin
  
  A 300mg dose of aspirin is often given to patients during a heart attack. Aspirin will help stop the clot in the artery from growing.


• Thrombolytics
  
  These dissolve the blood clots. These include alteplase and streptokinase. They should be injected into the patient as soon as possible. If the blood supply to the muscle can be restored soon enough, much of the affected heart muscle will survive.


• Painkillers
  
  Morphine is sometimes injected into the patient to control the pain and discomfort. Experts say this also reduces anxiety.

Treatment after the heart attack

Most patients will need several different medications after their heart attack. The aim being to prevent future heart attacks from occurring.

• Aspirin and other Anti-platelets
  
  Our blood has platelets. These are tiny particles that help the blood to clot. They can eventually, if they are very sticky, stick to fatty deposits, or plaques, and form a thrombosis. A thrombosis is a clot. A thrombosis in a coronary artery can cause a heart attack. Anti-platelets reduce the stickiness of the platelets.
  
  Patients are often prescribed a daily 75mg dose of aspirin - this is called low-dose aspirin. Those who have stomach ulcers may be given medication to prevent the aspirin from damaging their stomachs. Patients who suffer from asthma may be prescribed clopidogrel, rather than aspirin.


• Beta-blockers
  
  These drugs make the heart beat more slowly and with less force, thus easing the heart's workload. They also stabilize the heart's electrical activity. Examples include metoprolol, propranolol, timolol, and atenolol.


• ACE (Angiotensin-converting enzyme) inhibitors
  
  These drugs help ease the workload on the heart by opening up blood vessels and lowering blood pressure. Experts say ACE inhibitors also protect the heart from further damage. Patient will have a blood test to make sure their kidneys are working properly before starting on this type of medication. Then, about ten days after starting treatment, the patient will undergo further tests to make sure his/her kidneys are still working fine. Over a period of about 3 weeks the patient's dose is gradually increased. Examples of ACE inhibitors include lisinopril, perindopril and ramipril.


• Statins
  
  Statins make the liver produce less cholesterol, consequently lowering blood cholesterol levels. Patients with high cholesterol levels have a higher risk of developing fatty deposits in their blood vessels, especially their arteries. Statins include atorvastatin, fluvastatin, pravastatin, rosuvastatin and simvastatin.


• Surgery after a heart attack
  
  If the patient's heart has been severely damaged he/she may need to be operated on. The most common surgeries performed on heart attack patients are:


• Angioplasty
  
  This can be performed either after the heart attack, or in some specialist units during the attack. Angioplasty opens up the coronary artery. A small wire goes up the artery from the patient's groin or arm and is pushed until it reaches where the clot is in the coronary artery. There is a small balloon, shaped like a sausage, at the end of the wire. The balloon is placed at the narrowest part of the artery and is then inflated, squashing the clot away. A flexible metal mesh, called a stent, is then placed there to keep that part of the artery open.


• CABG (Coronary artery bypass graft)
  
  The damaged blood vessel is by-passed with grafts taken from blood vessels elsewhere in the body. The bypass effectively goes around the blocked area of the artery, allowing blood to pass through into the heart muscle.

Convalescing/recovering after a heart attack

Recovery from a heart attack can be a slow and gradual process. It may involve liaising with various types of health care professionals, including doctors, dieticians, nurses, physio therapists, pharmacists, and personal trainers. The patients' recovery will generally start in hospital, and then continue at home.

• Physical activity
  
  Experts say it is vital that a recovering heart attack patient try to stay active. Exercise is a crucial part of recovery, as it strengthens the heart muscles, and significantly lowers the risk of another heart attack. Most patients will be given some kind of exercise program while they are still in hospital. It is important that any exercise program is devised by an exercise specialist who is part of the patient's health professional team. Most initial exercise programs will be about 12 weeks long.
  
  Most heart attack patients are able to go back to their normal everyday domestic activities. Of course, this will depend on the patient's physical and mental state. Doctors advise most patients to take it easy at first.


• Going back to work
  
  When a heart attack patient can go back to work depends on various factors: The severity of the heart attack, the type of job, the physical status of the patient after the heart attack, the financial situation of the patient, etc.
  
  Some people are eager to get back to work for various reasons. It is vital that people do not rush back - a proper recovery period is needed to prevent recurrences. Patients should be guided by their doctors' advice.


• Heart attack and depression
  
  According to the National Health Service (NHS), UK, about one fifth of heart attack patients go on to have a major episode of depression not long afterwards. Another quarter of all heart attack patients experience minor depression or depressed moods.
  
  The patient should understand that it is common to feel depressed or anxious after a heart attack. The worry about being able to cope, losing one's job or work status, are contributory factors.
  
  The severity of the depression can influence the patient's rehabilitation - making recovery a slower process.
  
  Heart attack patients who feel depressed or anxious should tell their doctors immediately.


• Driving
  
  In the UK it is advised that a person refrains from driving for at least 4 weeks after his/her heart attack. Most countries will not require that the patient does another driving test. Patients who have other conditions should check with their car insurance company to make sure they are still covered before they start driving again. In the UK anybody who drives large goods vehicles has to tell the DVLA about their heart attack. In most cases they will not be allowed to drive for six weeks, and will only be able to do so after passing a basic health and fitness test.


• Erectile dysfunction after a heart attack
  
  Approximately one third of all men who have a heart attack suffer from erectile dysfunction - they have problems getting, or sustaining an erection. Experts say that sexual activity does not raise a person's risk of having another heart attack. It is important that men with erectile dysfunction talk to their doctors - in the majority of cases certain medications, such as Viagra (sildenafil citrate), Cyalis (tadalafil), and Levitra (vardenafil) are very effective at restoring erectile function. Other treatments are also available.

Complications after a heart attack

There are two types of complications, those that occur pretty much straight away, and those that happen afterwards.

Immediate complications

• Arrhythmias - the heart beats irregularly, either too fast or too slowly. Patients may be given cardioversion - an electric current is passed through the heart. Most patients, with time, will return to regular rhythms. There are also medications for arrhythmias.


• Cardiogenic shock - the patient's blood pressure suddenly drops dangerously. The heart cannot supply enough blood for the body to work adequately. The following drugs will raise blood pressure and heart functioning, Dopamine, Dobutamine, Epinephrine, and Norepinephrine.


• Hypoxemia - levels of blood oxygen become too low.


• Pulmonary edema - there is fluid accumulation in and around the lungs.


• DVT (deep vein thrombosis) - the deep veins of the legs and pelvis develop blood clots which either block or interrupt the flow of blood in the vein.


• Myocardial rupture - the heart attack damages the wall of the heart. This increases the risk of a heart wall rupture.


• Ventricular aneurysm - one of the chambers (ventricles) of the heart forms a bulge.

Complications that can occur later:

• Aneurysm - scar tissue builds up on the damaged heart wall. This leads to blood clots, low blood pressure, and abnormal heart rhythms.


• Angina - Not enough oxygen is reaching the heart. Symptoms may be similar to those of a heart attack, especially the chest pain.


• Congestive heart failure - the heart can only beat very weakly. The patient feels exhausted and breathless.


• Edema - fluid accumulates in the ankles and legs (they swell).


• Future heart attacks - a person who has had a heart attack runs a higher risk of having another one, compared to other people.


• Loss of erectile function - erectile dysfunction is generally caused by a vascular problem. However, it can also be the result of depression.


• Loss of libido - this is especially the case with men.


• Pericarditis - the lining of the heart becomes inflamed, causing serious chest pain.

Patients who comply with their doctors instructions have a much better chance of recovery than those who don't. It is important that the doctor monitor a heart attack patient for several months afterwards.

How to minimize your chances of having a heart attack in the first place:

• Don't smoke
• Eat a balanced, healthy diet
• Get plenty of exercise
• Get plenty of good quality sleep
• If you have diabetes, keep it under control
• Keep your alcohol intake down
• Keep your blood cholesterol at optimum levels
• Keep your blood pressure at safe levels
• Lose weight
• Maintain a healthy body weight
• Expose yourself to less stress
• Learn how to manage stress

Written by Christian Nordqvist


Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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