To work efficiently the heart needs a generous supply of oxygen and nutrients. These are supplied by the coronary arteries (blood vessels) and their branches.
If blood flow in one or both of the arteries is blocked, the heart is starved of oxygen and nutrients, and the cells of the heart muscle (myocardial cells) are damaged. This is a heart attack.
Fast treatment reduces heart damage
The quicker you get to the hospital the sooner you can receive treatment to re-open the blocked artery that is causing the heart attack. This helps to prevent permanent damage to your heart muscle.
What causes heart attack?
A heart attack is almost always preceded by the build-up of plaque in the arteries. This restricts the flow of oxygen-rich blood to the heart.
Factors that contribute to this narrowing and hardening of the arteries include:
- age (risk increases with age)
- gender (men are more at risk)
- family history
- lack of exercise
- being overweight
- poor diet
- high cholesterol
- high blood pressure.
Symptoms can vary
A heart attack can be mild, moderate or severe. The severity of the attack depends on how many myocardial cells are damaged or killed. Women's symptoms can be different from those in men.
Some people experience few symptoms or none at all, or confuse them with indigestion or heartburn. They can be similar to those for angina. Typical symptoms include:
- dull pain, chest tightness or discomfort that becomes more severe and does not go away; often described as ‘crushing'
- pain or heaviness in the arms, shoulders, back, throat or jaw
- nausea and vomiting
Damaged heart muscle
Even if you survive a heart attack, your heart muscle will still have been damaged. The longer an attack goes untreated, the greater the damage. This can affect your long-term health, and causes chronic conditions such as heart failure.
What is cardiac arrest?
A heart attack can ‘stun' the heart and interrupt its rhythm and ability to pump. Instead of beating normally, the rhythm can be chaotic (ventricular fibrillation) or stop the heart altogether, causing cardiac arrest.
A cardiac arrest can follow on from the symptoms of a heart attack or strike suddenly. Typically, the person falls unconscious, has no pulse and usually stops breathing.
Cardiac arrest is a medical emergency
Without immediate help, the person will die. Ambulance paramedics or hospital staff will need to use a special device called a defibrillator, which passes an electric jolt through the heart which may start it beating again.
If there is no specialised equipment, cardiopulmonary resuscitation (CPR) is crucial. This combines mouth-to-mouth resuscitation and heart massage. CPR can keep the person alive until an ambulance arrives.
If you think someone may be having a heart attack, regard this as an emergency. Do not waste vital moments. Rather than going to a doctor's clinic, take these steps:
- Dial triple zero (000) in Australia.
- Ask for ambulance service.
- Report a possible heart attack.
- Give the person an aspirin if you have any, unless they have been advised not to take aspirin.
- Make sure they rest quietly while you wait for transport or an ambulance.
- If an ambulance is not readily available (for example, in some rural areas), quickly notify the nearest hospital, health clinic or the person's usual doctor for advice.