Heart attack

What is a heart attack?

A heart attack (also known as myocardial infarction) occurs when at least one coronary artery closes completely. A blood clot which attaches itself to an arteriosclerotic constriction is generally responsible for the obstruction. As a result, a part of the heart muscle no longer receives oxygen. If this circulatory disorder is not treated immediately, this part of the heart muscle quickly dies.　

Scar tissue also forms in the heart muscle after a heart attack. This can cause cardiac arrhythmias or cardiac insufficiency.

Cause

A heart attack is usually caused by arteriosclerosis. The main risk factors for the occurrence of arteriosclerosis are:

• Smoking
• High blood pressure
• High cholesterol

If an already calcified coronary artery is completely closed by a blood clot, this causes a myocardial infarction.　　

Symptoms of a heart attack

Heart attack patients often suffer from angina pectoris with temporary circulatory disorders of the heart before a heart attack, the cause of which is calcification (arteriosclerosis) of the coronary arteries.

However, unlike angina pectoris, the symptoms of a heart attack are generally much stronger:　

• Severe chest pain or a feeling of tightness in the chest. This is accompanied by shortness of breath, nausea, sweating and fear of death. Doctors also call these clinical symptoms acute coronary syndrome.　　
• Milder pain which does not improve when a patient keeps still and lasts longer than 15 minutes. The pain also often radiates into the neck, the shoulders and the arms.

Diagnosis

If you suspect that someone is having a myocardial infarction, they must be immediately admitted to hospital. The doctor can quickly make the diagnosis with an ECG examination and by determining the troponin level in the blood. Troponin is a substance which occurs if the cells of the heart muscle are damaged. If a patient has an infarction, increased troponin levels will already be detectable in the blood soon after the event.

You can find out how to recognise a heart attack and what you can do at Heart attack: emergency first aid.

Treatment

It is vital that blood flow is restored to the heart muscle quickly after a diagnosis has been made. There are various options available. Depending on the situation, the blood clot responsible for the infarction can be dissolved with medication (thrombolysis), or the blocked blood vessel can be opened surgically.

Find out more about the surgical treatment methods using balloon dilatation, stent or bypass surgery in the section about Coronary arteries: operations and procedures.

After a myocardial infarction, existing risk factors usually require life-long treatment to prevent further attacks. Depending on the constellation, these include antihypertensives, cholesterol-reducing medication and blood thinners.