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What is a Heart Attack and How Does it Happen?

What is a Heart Attack and How Does it Happen?

Causes & Risk Factors

A heart attack or myocardial infarction (MI) is a medical emergency that requires immediate treatment. It happens when a section of the heart doesn’t receive adequate oxygen (cardiac ischemia) due to a blockage in blood flow. If the oxygen supply is not restored quickly, the affected cardiac muscle begins to die, resulting in a heart attack.


What is a heart attack, and how does it happen? At this point, we already know that a heart attack occurs when the cardiac muscle is starved of oxygen due to blocked circulation; but how does the blockage happen?

Atherosclerosis and Coronary Artery Disease (CAD)

The blockage usually occurs due to atherosclerosis, a process wherein the coronary arteries (blood vessels that supply the heart with oxygen) become clogged with plaque, a substance primarily made up of fat and cholesterol. Atherosclerosis then causes coronary artery disease or ischemic heart disease, in which the arteries are narrowed.

what is a heart attack and how does it happen

But, heart attacks don’t usually happen immediately after having atherosclerosis or CAD. Most cases of myocardial infarction take place after a plaque buildup ruptures or bursts, causing damage to the lining of the blood vessel.

To repair the damage, a blood clot forms on site. If the blood clot becomes too large, it may completely block the artery and prevent oxygen from reaching a section of the heart.

Spasm of the Coronary Artery

Cases of coronary artery spasm may be rare, but it still answers the question, how does a heart attack happen. Sometimes, people without CAD or atherosclerosis suffer from MI because their artery spasms or constricts on and off, depriving the heart of oxygen.

10 Ways to Prevent Atherosclerosis

Risk Factors

A heart attack is more likely to occur if a patient has the following risk factors. Notice that some of the risk factors below are modifiable, meaning you can control or eliminate them.

  • Age
  • Family history
  • Preeclampsia, a pregnancy-related condition characterized by high blood pressure and protein in the urine
  • Cigarette smoking
  • Overweight and obesity
  • Hypertension
  • High blood cholesterol
  • High blood sugar
  • Unhealthy diet
  • Sedentary lifestyle

People who have hypertension, high blood cholesterol, and obesity at the same time have a condition called metabolic syndrome. Patients with metabolic syndrome are twice more likely to suffer from a heart attack.

Signs & Symptoms

Now that we answered the question, how does a heart attack happen, let’s talk about its signs and symptoms. The most common symptoms of myocardial infarction include:

  • Chest pain that may radiate to the left arm, shoulder
  • Shortness of breath
  • Cold sweat or diaphoresis
  • Lightheadedness or dizziness
  • Tiredness or fatigue
  • Rapid or irregular heartbeat

Please note that the warning signs of a heart attack vary from person to person. Some patients suffer from excruciating chest pain, while others only have mild discomfort or do not feel anything at all.

Women, the elderly, and those with diabetes are also less likely to experience chest pain, but may present other symptoms like abdominal pain, shortness of breath, nausea, or vomiting. People who’ve had MI before do not necessarily experience the same symptoms if they suffer from another attack.

What are the Pre-Warning Signs of a Heart Attack?

When to Seek Medical Help

If you suspect a heart attack, seek medical help immediately. Do not resort to sleeping or resting to see if the symptoms will go away. The quicker your act, the earlier the treatment can start.

Treating MI within an hour after the onset of symptoms reduces the risk of long-lasting and possibly irreversible complications, such as cardiac arrest, arrhythmias, and heart failure.

Treatment & Management

Besides shedding light on the questions, what is a heart attack, and how does it happen, it’s also essential to learn about MI treatment.

After the doctor runs tests like ECG and blood tests to diagnose a heart attack, the immediate treatment goal is to restore oxygen supply and reduce damage through medications, medical procedures like coronary angioplasty, or surgery.


Patients suffering from MI might need:

  • Aspirin and other blood thinners to promote blood flow by reducing clots and preventing the blood from becoming too “sticky”
  • Thrombolytic to dissolve blood clots and reduce blockage in circulation
  • Nitro-glycerine and other pain relievers to improve chest pain and blood circulation
  • ACE inhibitors and beta-blockers to improve hypertension
  • Statins to improve blood cholesterol


If medications are not enough to treat or prevent another heart attack to happen, the doctor may recommend surgeries such as coronary angioplasty with stenting and coronary artery bypass surgery.

Coronary angioplasty with stenting

In this surgery, the doctor inserts a thin tube with a balloon in the groin area and into the heart’s affected artery.

Once it’s in the affected area, the doctor inflates the balloon, opening the narrowed vessel. To keep the artery open for a long time, the surgeon may also insert a metal mesh with slow-releasing medication.

Coronary artery bypass surgery

Should a heart attack happen and two or more major arteries are totally blocked, the doctor may perform coronary artery bypass surgery. This operation takes an artery from another part of the body and attaches it in the heart to “bypass” a blocked artery. This surgery aims to reroute the blood and ensure that it will reach the affected area.

Lifestyle Changes & Prevention

If you haven’t had a myocardial infarction before and want to prevent it, regular check-ups and screening (blood tests, ECG) are necessary as they allow your doctor to determine your risks.

The following measures likewise help lower your risk of MI:

  • Avoid smoking or work on quitting if you’re a smoker
  • Maintain a healthy weight
  • Perform regular exercise, preferably 30 minutes of moderate-intensity aerobic workouts daily
  • Have a healthy diet, with many servings of fruits, vegetables, and whole grains
  • Control your blood pressure and cholesterol
  • Manage stress as studies show that chronic stress increases the risk of MI
  • Limit alcohol intake

Lifestyle Changes to Improve Your Heart Health

In case you’ve suffered from a previous MI and are recovering, the above practices also reduce the risk of repeat attacks. However, the doctor may give you specific instructions on diet, exercise, medications, and other activities such as sex.


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Hello Health Group does not provide medical advice, diagnosis or treatment.

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Written by Lorraine Bunag, R.N. Updated Mar 11, 2021
Medically reviewed by Mia Dacumos, MD
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