Types of Heart Attack and its Causes

Types of Heart Attack and its Causes


Heart attacks are one of the most common forms of cardiovascular diseases and affects millions of people yearly around the globe. In fact, heart disease is the number 1 killer in Malaysia and according to Columbia Asia, Malaysians are now suffering from heart attacks much earlier than before with many in their 20’s and 30’s being victims. 

Well known as a serious medical emergency – heart attacks are not only extremely dangerous; they can oftentimes be fatal. This is because during a heart attack, blood flow to the heart is cut off, leading to severe oxygen deprivation and a condition called ischemia. Without a constant supply of blood and oxygen, the heart muscles weaken and eventually dies. When this happens, the heart is no longer able to pump blood to the rest of the body. Depending on the length and severity of the heart attack, this can eventually cause permanent brain and organ damage, and ultimately death. 

Types of Heart Attacks: NSTEMI & STEMI

Divided into 2 classes, heart attacks can be categorized as either the “classic” milder and more common NSTEMI (non-ST-segment elevation myocardial infarction) or the more severe STEMI (ST-segment-elevation myocardial infarction). While they may sound complicated, the names NSTEMI and STEMI actually come from the change or lack of change to the heart’s electrical activity between heartbeats called the ST Segment in an electrocardiogram (ECG). When there is a high elevation change in the ST segment of the ECG, it indicates a large amount of damage in the heart muscle.

 

ECG Diagnosis Example Diagram from Cleveland Clinic

 

But what causes a heart attack (myocardial infarction)?

In most cases, a heart attack is caused by a blockage in the coronary artery (blood vessel that supplies oxygen-rich blood to the heart muscle) due to an obstruction such as a build-up of fatty deposits called plaque, a blood clot, or other conditions such as a spontaneous coronary artery dissection  (tear in the artery walls) and a coronary artery spasm (muscle constriction that causes the blood vessels to narrow). The main culprit, however, is coronary heart diseases (CHD), sometimes called coronary artery disease (CAD)*.

  • NSTEMI (Non-elevated): Partial blockage of a major coronary artery or a complete blockage of a minor coronary artery, leading to partial heart damage. Treatment is typically focused on restoring blood circulation while preventing further formation of blood clots.

  • STEMI (Elevated): Complete blockage of a major coronary artery, leading to extensive heart damage, serious health complications, and potential death.

*CAD and CHD are not necessarily the same as CAD refers to the disease process affecting the coronary arteries while CHD can apply to other diagnoses such as angina, myocardial ischemia, coronary microvascular disease, and many others.  In most cases, CHD is usually the result of CAD. These days, however, due to their high correlation with one another, they are often used interchangeably.  

What is coronary heart disease  (CHD) and how am I at risk?

Coronary heart disease  (CHD) is the narrowing of the blood vessels that supply blood and oxygen to the heart. It is often caused by atherosclerosis, an inflammation and build-up of materials and fatty deposits called atheromatous plaque (atheroma) within the coronary arteries that cause a thickening or hardening of the artery walls. At times, pieces of plaque can also break off, triggering the body’s blood clotting response and causing further blockages.

For many people, plaque can begin sticking to the lining of the artery walls as early as childhood. There, it continues to build up over time with various controllable and uncontrollable risk factors playing a role. These include:

  • Family history

  • Age

  • Ethnicity

  • High blood pressure

  • High cholesterol

  • Metabolic syndrome

  • Smoking

  • Diabetes

  • Being overweight

  • Lack of physical activity

  • Unhealthy diet

  • Stress and poor mental health

  • Alcohol

While some factors such as family history, age, and ethnicity are beyond control, ensuring a healthy lifestyle is key in helping keep other risk factors at bay. An additional way to mitigate the risks of a sudden heart attack is through the regular tracking of your blood pressure. This is because any sudden increase or decrease in blood pressure may indicate a blockage or an oncoming attack. Abnormal blood pressure readings can also indicate other health issues which may increase your risk.

So why not measure your own blood pressure daily? Get your own electronic blood pressure monitor today.

Remember, all forms of heart attacks are dangerous – and even a short amount of time can cause irreversible damage. If you feel any discomfort or chest pains, or suspect you may be at risk of developing a heart attack, hurry to your nearest hospital or doctor. 


References/Sources: Yayasan Jantung Malaysia, British Heart Foundation, Centers for Disease Control and Prevention, NHS UK, WebMD, Health Direct, Texas Heart Institute, NIH, Animal Models for the Study of Human Disease (Second Edition), 2017, Cleveland Clinic, Verywell Health,

 

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