Heart Attack

A heart attack, also known as a myocardial infarction, is a serious medical emergency where blood flow to the heart is interrupted, usually due to a blood clot in the coronary artery. This causes a lack of oxygen to the heart muscle and may affect proper functioning of the heart.

Other medical terms for a heart attack include:

• Acute myocardial infarction (AMI)
• Acute coronary syndrome (ACS)
• Coronary thrombosis

One of the leading causes of death in Singapore, a heart attack happens when blood stops flowing to a part of your heart muscle. If not attended to immediately, a heart attack could lead to permanent heart damage or even death.

There are different types of myocardial infarction (MI), based on what is seen on the ECG. The two main types of heart attacks are:

• ST segment elevation myocardial infarction (STEMI)
  Usually the classic heart attack, a STEMI is caused by a sudden complete blockage of the coronary artery from a blood clot, and a large part of the heart muscle stops receiving blood. This type of heart attack could cause significant damage to your heart.

• Non-ST segment elevation myocardial infarction (NSTEMI)
  A NSTEMI is usually due to partial blockages of the coronary artery, depriving the heart muscle of receiving enough blood for normal functioning. The degree of damage to the heart is usually less, but it is a very serious condition.

A heart attack is caused by blockages of one or more of your coronary arteries in the heart, interrupting blood flow to the heart muscle.

These blockages are commonly due to underlying coronary artery disease (atherosclerosis) — where plaque, made up of fat and other substances, collects along the lining of an artery, narrowing the passageway where blood flows. A blood clot may form which can block blood flow through the artery and cause a heart attack.

Other causes are much less common, which include spontaneous coronary artery dissection (where one or more of the coronary arteries tear, coronary vasospasm (where the coronary arteries tighten and caused blood flow to reduce), and other medical conditions that cause supply-demand imbalances of blood flow to the heart muscle.

It is important to understand your risk factors for a heart attack, as some of these are within our control and could be changed, such as certain lifestyles and habits.

• Age — Chances of getting a heart attack increase with age, with the majority of people dying from coronary heart disease being 65 years or older. However, a heart attack can happen in someone younger.
• Males — Men are at greater risk of having a heart attack than women.
• Heredity — People with a family history of heart disease are at risk of developing heart disease themselves.
• Smoking — Cigarette smoking puts one at a much higher risk of developing coronary heart disease compared to non-smokers.
• High blood cholesterol — High blood cholesterol also puts you at higher risk of heart disease.
• High blood pressure — High blood pressure puts more strain on the heart, causing the heart muscle to thicken and stiffen. This affects its ability to function optimally.
• An inactive lifestyle — A sedentary lifestyle with little physical activity may increase your risk of having a heart attack.
• Obesity — People who are obese or overweight are at a higher risk of developing heart disease.
• Diabetes — Having diabetes greatly increases your risk of developing heart disease, especially if your blood pressure is not managed properly.
• Diet — An unhealthy diet with too much processed and red meat, sugar-sweetened drinks, sodium-rich and oily food put you at higher risk of developing cardiovascular disease. Drinking too much alcohol can also raise blood pressure and, in turn, increase your risk.
• Stress — Chronic stress may pose a risk for heart attack and stroke.

Although some risk factors may not be within our control, certain factors are modifiable and manageable, such as our diet and nutrition, smoking, physical activity and environmental stressors. Prevention is always better than cure, and it would help to consult a doctor for regular physical exams in order to properly assess your risk factors and work to keep them low.

Heart attack symptoms can vary in intensity and duration. The initial signs that indicate an oncoming heart attack can include heaviness, tightness, pain or discomfort in the:

• Chest
• Shoulder
• Jaw
• Arm
• Neck
• Mid-back

These sensations may also be accompanied by cold sweats, difficulty breathing, nausea, light-headedness or tiredness.

If you experience any of these symptoms, it is paramount that you alert someone nearby and call an ambulance. It is important to get medical attention immediately because a heart attack if left untreated, can lead to serious complications or even death.

There may be instances where none of the above signs are present and you experience only a type of discomfort, akin to acid reflux or indigestion. This is called a silent heart attack and usually occurs among people with diabetes.

Damage to the tissues of the heart caused by a heart attack could lead to very serious complications such as:

• Weakening of heart muscles
• Heart failure
• Abnormal heart rhythm (Arrhythmia)
• Myocardial rupture
• Cardiac arrest
• Death

If you have chest pain that is new, severe, prolonged or causing concern, call 995 for an ambulance immediately. The ambulances are prepared to respond rapidly, and they will take you to the nearest hospital. For someone having a heart attack, every minute is important. Remember, the faster you get to a hospital, the sooner you can receive treatment.

In the hospital, your doctor will run tests such as:

• Electrocardiogram (ECG)
  An ECG is critical in diagnosing a heart attack. The ECG pattern can indicate the type of heart attack, as well as the presence of any dangerous heart rhythm (arrhythmia) caused by the heart attack.
• Blood tests
  Samples of your blood may be analysed for certain heart-specific proteins or enzymes that indicate damage to the heart muscle during the heart attack.

• Coronary Angiogram
  A coronary angiogram is a minimally invasive procedure where a catheter is placed through a small incision at your wrist or groin vessel to reach the opening of the coronary artery. Following injection of contrast dye through the catheter under live X-ray, the location and severity of coronary blockages are immediately determined.

A coronary angiogram is vital in the diagnosis and treatment of a heart attack due to coronary artery blockages. Depending on the ECG pattern, the coronary angiogram is done either immediately as an emergency (for STEMI), or as early as possible within the next few days (for NSTEMI).

Following the coronary angiogram, coronary angioplasty, or percutaneous coronary intervention (PCI) is usually done to open the blocked arteries and restore normal blood flow. This treatment is vital especially for STEMI to limit the extent of heart muscle damage and can potentially save your life.

The doctor may carry out further tests to get a better understanding of your condition, such as:

• Chest X-ray
• Echocardiogram
• Cardiac CT or MRI

Immediate medical attention and prompt treatment are paramount to prevent further damage to the heart by restoring blood flow as soon as possible. The type of heart attack determines the course of treatment.

Implanting a stent during PCI

Coronary Angioplasty/ Percutaneous coronary intervention (PCI)

A coronary angioplasty, or PCI, is a minimally invasive procedure following a coronary angiogram where small devices are used to unblock the coronary arteries. A small balloon is passed through the catheter into the coronary artery until the point of blockage. The balloon is then inflated and this opens up the narrowing. Following this, a stent is usually implanted to keep the vessel open. Other devices may be used during the procedure to remove blood clots.

PCI is the preferred method for the immediate treatment of STEMI and is accessible as an emergency treatment (“Primary PCI”) throughout the whole of Singapore. In countries and regions not equipped with emergency PCI services, an acceptable alternative treatment is to use a clot-busting medication called thrombolytics that dissolves blood clots.

Medications

You may receive medications such as, but not limited to:

• Aspirin, a type of antiplatelet medication which helps reduce blood clotting.
• Antiplatelet medications (such as Clopidogrel or Ticagrelor) in addition to aspirin, to prevent further blood clots and reduce the risk of another heart attack
• Angiotensin-converting enzyme inhibitors (ACE-i) helps in blood pressure, aids in the recovery of heart muscle function and improves blood flow to the body.
• Beta-blockers are used to regulate heart rhythm, reduce stress on the heart and help in blood pressure.
• Nitrates are used to dilate blood vessels and relieve chest pain or pressure.
• Statins reduce cholesterol levels and slow the progression of further cholesterol accumulation in the blood vessels.

Coronary artery bypass graft (CABG)

Coronary bypass surgery treatment following a heart attack is much less common. Coronary bypass surgery is usually reserved for patients with multiple and extensive coronary artery blockages not suitable for angioplasty, or if the results of the initial angioplasty is not good enough for the long term. Coronary bypass surgery is done under general anaesthesia. During the surgery, the surgeon takes healthy blood vessels from the chest, arm or leg to create a graft to bypass the blocked coronary arteries. This new path allows blood to flow around the blocked or narrowed artery, improving blood flow to the heart  .

Your doctor will advise you on the best treatment option based on your condition.

Yes, Singaporeans and PRs are eligible for a Medisave claim for their treatment in the event of hospital admission.

If there are no complications during or after your heart attack, you can usually leave the hospital after 3-5 days. Upon discharge, your doctor will give recommendations on your weight, diet, physical activity, medication and other lifestyle changes. It is important to follow these recommendations to aid in your recovery and to avoid any future attacks.

You may also be enrolled in a cardiac rehabilitation programme, designed to guide you in improving your cardiovascular health through education and exercise counselling and training.

Your heart will take about 4-6 weeks to repair itself and there are certain activities to note:

• Physical activity can aid in your recovery. However, you should avoid overly strenuous activities in the first few weeks and only start your activity gradually on the advice of your doctor.
• Air travel should be avoided for a month or two after a heart attack.
• Sexual intercourse may resume when you can carry out light exercises without feeling breathless or tired.
• Work can resume when the doctor certifies that you are fit to return to work.
• Minimise stressors and engage in stress management practices, such as a proper work-life balance.
• Medication, in conjunction with other healthy lifestyle practices, is vital and must be taken even after the angioplasty.

Hopefully, this article has helped better explain what a heart attack is, what signs to look out for and the treatment you can expect should you need it.  During a heart attack, timely treatment is key to restore blood flow and limit the damage to the heart. Together with essential heart medications and making healthy lifestyle changes, visit your doctor regularly to ensure a full recovery after a heart attack.

If you believe you may be having a heart attack, you must immediately call 995 for an ambulance to go to the A&E. Do inform a family member. Do not drive yourself to the hospital. Take a GTN tablet or spray if you have it with you.

If you have symptoms suggestive of coronary artery disease, have one or more risk factors, or if you are thinking of embarking on a new exercise program, do consult a Cardiologist early.