What is it?
Heart attack also known as myocardial infarct is usually caused by a blockage in blood supply to the heart muscles when the blood vessels supplying the heart (coronary arteries) are occluded. The most common causes are from atherosclerotic plaques (fatty deposits) built up within the lumen of the blood vessels, or from blood clots that block off the heart's blood supply. (Please see section on Coronary Artery Disease) Prompt treatment is of the essence to prevent progression to permanent damage to large areas of the heart.
Scar tissue will replace the heart muscle that dies as a result of the myocardial infarct.
How is it diagnosed?
Your doctor will diagnose a heart attack based on
The symptoms you are experiencing (see below)
Your medical history
Risk factors, eg. known history of heart disease, smoking, diabetes, family history of heart attacks
Test results, eg. ECGs, blood tests for cardiac enzymes, chest X rays (to look for fluid in the lungs, a sign of poor cardiac function)
A combination of all of the above will lead to a definitive diagnosis of a heart attack.
What are the symptoms?
The most common presenting symptom is central chest pain, which can occur both at rest and on exertion. The nature of this pain is more severe, and lasts longer than the normal chest pain. The pain can travel up the jaw, to the left or both arms. It is often associated with sweating, shortness of breath, nausea, and/or vomitting. The patient may look pale as well. A smaller heart attack can be very similar to an episode of heartburn.
About one fifth of patients, often the elderly and the diabetic, have no pain at all, and only present with symptoms of compromised heart function, such as shortness of breath, low blood pressure, palpitations/irregular heart rhythms (Please see section on Heart Arrythmias).
A very severe heart attack can cause some patients to suddenly collapse and die.
What is the treatment?
If you are outside of a hospital:
Once in a hospital:
The heart muscles that were affected during a myocardial infarct do not die off immediately. If the flow of blood and hence oxygen is restored to these muscles as soon as possible (within a few hours), much of the muscle cells will survive. This is the reason for prompt treatment. There are two ways in which this can be achieved:
Thrombolysis: This method uses medications that can break down any clots that are the cause of the myocardial infarct, and in doing so allow reperfusion of the infarcted heart muscles. These agents can achieve reperfusion in 50-70% of patients if administered as soon as possible, to reduce mortality and morbidity. Thrombolysis carries with it risks, including increased risks of haemorrhage (bleeding). Therefore, it will be unsuitable in patients who have had a recent major bleed, stroke, uncontrolled hypertension, recent surgery or bleeding disorders.
: A thin wire with a ballon at the end will be passed into the blocked coronary artery via a vessel in the groin or arm. The balloon is then inflated inside the blocked/narrowed artery to widen it, allowing blood to flow again. A stent may be placed as well to keep the vessel widened.
Because of the increased risks of fatal heart arrythmias developing after a heart attack, you may be transferred to a Coronary Care Unit (CCU) for closer monitoring and intervention if required. ECGs and blood tests will be carried out over the course of your stay to monitor your progress.
Once you are fit for discharge, you will need to control risk factors of heart disease, such as stopping smoking, optimising diabetic control, and controlling the cholesterol levels in the blood. Drugs are also commonly prescribed to prevent a further myocardial infarct, and examples of them are aspirin (to make the blood "thinner" to prevent blood clots from forming), and a beta blocker (slows the heart rate down).