What is a heart attack?
A heart attack happens when blood flow to part of the heart is suddenly blocked — usually because of a blood clot. Without blood, that part of the heart muscle is starved of oxygen and begins to die. The faster blood flow is restored, the more of the heart can be saved.
Heart attacks are a medical emergency. If you or someone nearby experiences symptoms, call 000 immediately.
What causes a heart attack?
Most heart attacks are caused by coronary artery disease — a condition where the arteries that supply blood to the heart gradually become narrowed by a build-up of fatty deposits called plaque. This process, known as atherosclerosis, can develop silently over many years.
A heart attack typically occurs when a piece of plaque ruptures, triggering the formation of a blood clot that partially or fully blocks the artery. When blood can't get through, the heart muscle downstream begins to suffer damage.
Some heart attacks can also occur when an artery goes into sudden spasm, temporarily cutting off blood flow, though this is less common.
What's the difference between a heart attack and cardiac arrest?
These terms are often used interchangeably, but they're not the same thing.
A heart attack is a circulation problem — a blockage stops blood reaching the heart muscle. The heart usually keeps beating, but it's being damaged.
Cardiac arrest is an electrical problem — the heart suddenly stops beating altogether. Cardiac arrest can be triggered by a heart attack, but can also happen for other reasons. It requires immediate CPR and defibrillation.
What are the symptoms?
Heart attack symptoms vary from person to person. The classic warning signs include chest pain or pressure — often described as a heaviness, tightness or squeezing sensation — that may spread to the arm, jaw, neck or back. Other common symptoms include shortness of breath, nausea, light-headedness and breaking out in a cold sweat.
Not every heart attack feels dramatic. Some — particularly in women and people with diabetes — can present with more subtle symptoms such as fatigue, nausea or upper back pain, without the classic chest pain. This is sometimes called a "silent" heart attack.
If something feels wrong, don't wait to see if it passes. Call 000.
Who is at risk?
Some risk factors are things we can't change — getting older, being male, and having a family history of heart disease all increase the risk. But many of the most significant risk factors are ones we can act on, including high blood pressure, high cholesterol, type 2 diabetes, smoking, physical inactivity, being overweight and chronic stress.
Having one risk factor raises your risk. Having several multiplies it considerably.
Can heart attacks be prevented?
Many heart attacks can be prevented — or at least significantly delayed — through a combination of lifestyle changes and, where appropriate, medication.
Eating a heart-healthy diet, staying physically active, not smoking, maintaining a healthy weight and managing stress all play an important role. If you have high blood pressure, high cholesterol or diabetes, working with your doctor to keep these under control is one of the most effective things you can do.
How is a heart attack treated?
Time is critical. The sooner a blocked artery can be reopened, the less damage occurs. In hospital, treatment typically involves either a procedure called a percutaneous coronary intervention (PCI) — where a small balloon is used to open the blocked artery and a stent is placed to keep it open — or clot-dissolving medication called thrombolysis.
After a heart attack, recovery includes medication, cardiac rehabilitation and lifestyle changes to reduce the risk of another event.