Tasha (not her real name), a 45 year old lady, had been feeling some occasional left sided chest pain on and off for a few months. She had not gone to see the doctor, as she often thought that it was just a heart burn. She got concerned however, that the pains could worsen during periods of exercise such as walking or climbing the stairs, or doing aerobics at the gym. She thought to herself that probably her uncontrolled blood pressure and her weight may be contributing, as she was overweight. She planned to see the doctor for a more comprehensive medical check-up. One day however, while cleaning dishes in her house, she felt a sudden sharp pain on the left side of her chest. The pain persisted and spread to her left shoulder. It was unbearable as she was sweating and having difficulty breathing. She had such a terrible sense of impending doom. She could not stand anymore and fainted. She later found herself in hospital, and on oxygen (a close relative who was with her in the house had called for an ambulance).

When she came to her senses, the cardiologist explained to her that she had suffered a heart attack and one of the major arteries supplying blood to her heart was almost completely blocked. The doctor further said that she was lucky to have been brought to hospital in good time before the damage to her heart had gotten worse. She had never imagined herself getting a heart attack, let alone having a heart problem. An operation to unblock her coronary arteries was done as an emergency. After the surgery, she stayed on in hospital for some time but eventually recovered well.

What is a heart attack?

A heart attack is also called a myocardial infarction. It is usually caused by a blockage of one of the main arteries that supply the heart muscles. These arteries are called coronary arteries

The part of the heart muscle supplied by the blocked artery loses its blood (and oxygen) supply and is at risk of dying unless the blockage is quickly removed. When a part of the heart muscle is damaged it is said to be infarcted. The term myocardial infarction (MI) means damaged heart muscle.

If a major coronary artery is blocked, a large part of the heart muscle is affected. If a smaller branch artery is blocked, a smaller amount of heart muscle is affected. After a heart attack, if part of the heart muscle has died, it is replaced by scar tissue over the following few weeks. The scar tissue causes the heart to be weak and it can enlarge over time, and even lead to heart failure, a condition where the heart does not do its work of circulating blood properly.

Understanding the heart and coronary arteries

The heart is mainly made of special muscle (myocardium). The heart pumps blood into blood vessels (arteries) which take the blood to every part of the body. Like any other muscle, the heart muscle needs a good blood supply. The coronary arteries take blood to the heart muscle. The main coronary arteries branch off from the aorta. The aorta is the large artery which takes oxygen-rich blood from the heart chambers to the body. The main coronary arteries divide into smaller branches which take blood to all parts of the heart muscle. 

What causes a heart attack?

The most common cause of a heart attack is a blood clot that forms inside a coronary artery, or one of its branches. This blocks the blood flow to a part of the heart.

Blood clots do not usually form in normal arteries. However, a clot may form if there is some fatty patches or plaques that develop within the inside lining of arteries. These plaques form over a number of years in one or more places in the coronary arteries. The plaques are mostly associated with high cholesterol levels in the blood. A plaque can rupture and trigger the clotting mechanism causing a blood clot.

Who is at risk of having a heart attack?

Heart attacks are common. Most occur in people aged over 50 and it becomes more common with increasing age. Younger people are also getting affected these days because of lifestyle

A heart attack may occur in people known to have heart disease, such as people with chest pain called angina. It can also happen out of the blue in people with no previous symptoms of heart disease. Risk factors for a heart attack include smoking, high blood pressure, being overweight, high cholesterol, lack of exercise, unhealthy diets, diabetes, family history of heart disease

What are the symptoms of a heart attack?

The most common symptom is severe chest pain, which often feels like a heavy pressure feeling on your chest. The pain may also travel up into your jaw and down your left arm or down both arms. You may also sweat, feel sick and feel faint. You may also feel short of breath. The pain may be similar to angina (chest pain occurring during physical activity or at rest), but it is usually more severe and lasts longer. The pain can sometimes feel like indigestion or heartburn. Occasionally, a heart attack happens without causing any pain and only noted on ECG. Sudden collapse and death may be caused by a heart attack

Women who suffer a heart attack may not present with the classic heart attack symptoms experienced by men. Many women experience vague or even “silent” symptoms that they may miss.

How is a heart attack diagnosed and assessed?

• A heart tracing (electrocardiograph, or ECG). There are typical changes to the normal pattern of the ECG in a heart attack. Patterns that occur include things called pathological Q waves and ST elevation. However, it is possible to have a normal ECG even if you have had a heart attack.

• Blood tests. A blood test measures chemicals called troponin and creatine kinase and confirms a heart attack. This chemicals are present in heart muscle cells. Damage to heart muscle cells releases the chemicals into the bloodstream.

Other tests may be done in some cases include an ultrasound scan of the heart (echocardiogram) or a test called a myocardial perfusion scan. An angiography of the coronary arteries may also be performed to assess the severity of the fatty patches or plaques in the coronary arteries.

What is the treatment for a heart attack?

• Aspirin and other antiplatelet medicines, such as clopidogrel are given as soon as possible after a heart attack is suspected. They work on the blood clot to improve blood flow to the heart muscles
• Injections of anticoagulants such as heparin help prevent further blood clots from forming.
• Strong pain relief: such as morphine
• Other medicines that may be used include Beta-blockers toprotect the heart muscle, insulin to control your blood glucose and oxygen which reduces the risk of further damage to your heart muscle.

Treatment to restore blood flow in the blocked coronary artery

A heart attack is a medical emergency and treatment is given urgently to restore blood flow to the injured muscles. Treatments include:

• Emergency angioplasty is the best treatment. A tiny wire with a balloon at the end is passed up to the heart and into the blocked section of a coronary artery to widen it

• An injection of a clot-busting medicine, such as streptokinase is an alternative to emergency angioplasty. It can be given easily and quickly in most situations.

Complications of a heart attack include heart failure especially when a large area of the heart muscle is damaged then the pumping ability of the heart may be reduced. Suffering a heart attack also increases the risk of a further heart attack in future. Abnormal heart rhythms may occur if the electrical activity of the heart is affected. This is called ventricular fibrillation and is the common cause of cardiac arrest. This needs immediate treatment with an electrical shock given by a defibrillator. Otherwise, collapse and sudden death are likely.

To avoid the risk of getting a heart attack, exercise regularly, eat healthy diets low in salt, low in bad cholesterol such as red meats, high in omega-3 fatty acids and rich in vitamins from fruits and vegetables. Maintain a healthy weight, limit intake of refined sugar, manage your blood pressure, stop smoking. Finally, have regular medical check ups.