What is a heart attack?
The heart is a fist-sized organ lying in the centre of the chest. Its main function is to pump blood and supply oxygen to the rest of the body. For the heart to function well, the heart muscle requires oxygen as well.
Coronary arteries are blood vessels designated specifically for the heart muscle to receive oxygen-rich blood.
In coronary artery disease, the lumens within the coronary arteries are narrowed due to plaques which are composed of cholesterol, calcium and inflammatory cells deposited within the arteries, resulting in reduced blood flow.
If the narrowing is significant, the amount of blood supply may not be able to meet the demand of the heart muscle, especially during exertion or exercise. In such instances, the heart muscle suffers myocardial ischemia and signals to the person through ‘chest pain.’ When the exercise or exertion stops, the pain is relieved as the person rests. This is a form of stable angina, which is not life threatening.
On the other hand, when a plaque suddenly ruptures, platelets in blood that aid clotting, form blood clots around the plaque, and if this results in a total occlusion or complete blockage of the artery, the heart muscle will be deprived of oxygen. Within a short time, heart muscle cells start to die – this is a heart attack, or also known as myocardial infarction, and it can be fatal.
Figure 1: Plaque rupture and Muscle death during Heart attack
Is every chest pain a sign of heart attack?
Figure 2: Symptoms of Heart Attack (Thomas, 2015)
The most obvious and common symptom of a heart attack is severe chest pain, usually described as an uncomfortable pressure, or heavy, crushing sensation. This chest discomfort usually lasts longer (more than 20 minutes), and is not relieved with rest or medication. Sometimes, the pain may radiate to the back, jaw, neck and arms.
The feeling of chest discomfort may also be accompanied by shortness of breath, sweating and nausea. Some women may experience less central chest pain, but more of pain in the lower chest or upper abdomen, along with the feeling of dizziness and breathlessness.
However, up to 25% of heart attacks may be clinically silent; some people may have a heart attack without any symptoms (silent myocardial infarction). A silent heart attack can occur in anyone, but occurs more commonly among people with diabetes.
Yet, not every chest pain is a sign of heart attack. Severe heart burn (indigestion) may feel very much like angina and heart attack. In heartburn, stomach acids rise up into the swallowing tube (oesophagus) and may also cause chest pain that radiates to neck, throat or jaw. Chest pain may also be caused by other structures in the chest cavity, including the lungs, muscles and ribs.
So, am I having a heart attack? What should I do if I have chest pain?
To confirm the diagnosis of heart attack, one would require an ECG (electrocardiogram), blood tests, and sometimes an echocardiogram (heart scan). In event of severe chest pain, it is essential to act immediately, and not delay for too long. If indeed it is a heart attack, heart muscle cells are dying. In order to save as many of them as possible to minimize the extent of damage to the heart muscle, the diagnosis has to be made quickly, and the blocked artery needs to be opened as early as possible. This can be done relatively quickly and safely by an emergency angioplasty procedure.
If you suspect that you are having a heart attack, do not hesitate to call for emergency medical help. Do not drive to the hospital. Instead, find help to get to the nearest hospital or wait for an ambulance.
I have chest pain occasionally, is it worthy of concern?
If your chest pain occurs especially when you exert yourself or exercise, and goes away with rest, it can be stable angina, which may indicate possible significant blockage in your coronary arteries. This warrants a visit to a cardiologist, and it is advisable to get your heart checked early.