A heart attack is a serious medical emergency in which the blood supply to the heart is compromised due to a blockage in one of the arteries supplying blood to the heart, usually due to a clot. Lack of blood for even small periods of time can seriously damage heart muscles, and cause them to die.
Most heart attacks occur in people with pre existing heart conditions, usually referred to as coronary heart disease. The two main arteries that supply the heart are called the coronary arteries, and coronary disease refers to disease such a deposition of cholesterol in either or both of the arteries, leading to blockage.
Risk factors for coronary artery disease include
- high fat diet
Most heart attacks occur in people who are over 45 years of age. Men are two to three times more likely to have a heart attack than women.
Over the last decade, death rates from heart attacks have fallen by around 40%. This may be related to an associated decrease in the number of people smoking cigarettes.
The outlook for people who have a heart attack is highly variable and is dependent on two important factors:
- how quickly they receive treatment after the onset of the heart attack (ideally treatment should begin within 90 minutes of the onset of symptoms)
- how well they respond to treatment within the first 28 days after the heart attack
Currently, just over half the people who have a heart attack die during the first 28 days after the heart attack. Of these deaths, 75% occur in the first 24 hours and 30% of them occur before the person is admitted to hospital.
If a person survives for 28 days after having a heart attack, their outlook improves dramatically and most people will go on to live for many years.
In those who survive a heart attack, a combination of lifestyle changes and medication is usually recommended to reduce the risk of having another heart attack.
SIGNS AND SYMPTOMS
Dial your emergency services number immediately if you suspect that yourself or someone you know may be experiencing a heart attack. The symptoms to look out for are:
- chest pain: the pain is usually located in the centre of your chest and can feel like a sensation of pressure, tightness or squeezing
- pain in other parts of the body: it can feel as if the pain is travelling from your chest to your arms (usually the left arm is affected but it can affect both arms), jaw, neck, back and abdomen
- shortness of breath
- an overwhelming sense of anxiety (similar to having a panic attack)
- feeling light headed
The level of pain can vary significantly from person to person. For many people, the pain is severe and it has been described as feeling like ‘an elephant was sitting on my chest’. However, this is not always the case. For others, the pain can be minor and is similar to that experienced during indigestion. Also, some women and older people do not experience any chest pain at all.
*If you know that you are not allergic to aspirin and aspirin is easily available, chew (do not swallow) an adult size tablet while you are waiting for the ambulance to arrive. The aspirin will help to thin your blood and restore the blood supply to your heart.
An electrocardiograph (ECG) is an important test in cases of suspected heart attacks. An ECG should be carried out within 10 minutes of being admitted to hospital.
Heart attacks can be classified by a measurement that is known as the ST segment. The ST segment is an electrical measurement that is recorded by an ECG. It corresponds to the level of damage that has been inflicted on the heart. The higher the ST segment, the greater the amount of damage that is likely to have occurred.
There are three main types of heart attack:
- ST segment elevation myocardial infarction (STEMI)
- Non-ST segment elevation myocardial infarction (NSTEMI)
- unstable angina
The damage to your heart that results from a heart attack causes certain enzymes to slowly leak into your blood, called troponins. Troponins may be ordered immediately, but they elevate over a number of hours after the heart attack, and then come down slowly over the course of the next few days.
Chest Xray may also be performed as one of the earlier tests.
Coronary angiography can help determine whether a blockage or narrowing has occurred in the coronary arteries and, if so, to locate the exact location of the blockage or narrowing.
The test involves inserting a thin tube, known as a catheter, into one of the blood vessels in the patient’s groin or arm. The catheter is guided into the caronary arteries using X-rays.
A special fluid, known as a contrast agent, is pumped through the catheter. This fluid shows up on X-rays. Studying how it flows around and through the heart can help locate the site of any blockage or narrowing.
A coronary angiogram is often performed just before surgery because the results can help guide the efforts of the surgeon.
Treatment plan will depend on the type of heart attack a patient has had. For example, for an ST segment elevation myocardial infarction (STEMI), there are two treatment options:
- a combination of medication to dissolve the blood clot and restore the flow of blood to the heart (this is known as thrombolysis)
- surgery to widen the coronary artery, which is usually done using a technique called coronary angioplasty
If the patient had a non-ST segment elevation myocardial infarction (NSTEMI) or unstable angina, thrombolysis is usually recommended as the first treatment option.
If symptoms do not improve, a coronary angioplasty can be carried out.
RECOVERING FROM A HEART ATTACK
Recovering from a heart attack can take several months and it is very important not to rush your rehabilitation.
There are two important aims of the recovery process:
- to reduce your risk of experiencing another heart attack
- to gradually restore your physical fitness so that you can resume normal activities (known as cardiac rehabilitation).
There are currently four medications that are widely used to reduce the risks of heart attacks. These are:
- angiotensin-converting enzyme (ACE) inhibitors