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  3. Myocardial Infarction Definition: Symptoms and Treatments

Myocardial Infarction Definition: Symptoms and Treatments

Heart Attack

What is a Myocardial Infarction?


my·o·car·di·al in·farc·tion

/mīəˌkärdēəl inˈfärkSH(ə)n/

Myocardial Infarction: The Basics

Myocardial Infarction Definition (MI) is the medical terminology for “Heart Attack,” a condition in which a portion of the heart does not receive an adequate supply of oxygenated blood (ischemia). The continued lack of oxygenated blood results in part of the heart muscle dying (myocardial necrosis). The myocardium is the heart muscle, and infarction is a term used to refer to the death of the tissue, thus a “Myocardial Infarction” is literally “death of heart muscle.”

Incidence of MI:

  • Leading cause of death of both men and women in the United States
  • Over 700,000 Americans have heart attacks annually

Risk Factors for Heart Attack:

Patients who present with Myocardial Infarction often have one or more of the following risk factors:

  • Hyperlipidemia: High levels of cholesterol are highly associated with heart attacks, as the cholesterol builds up in the arteries, creating plaques which lead to clots that block coronary arteries.
  • Hypertension: High blood pressure is associated with myocardial infarctions. The high pressure causes damage to the walls of the arteries and can also cause built up plaque to rupture and form a clot.
  • Obesity: A high BMI increases the risk of Myocardial Infarction
  • Smoking: Patients are at an increased risk for Myocardial Infarction if they smoke.
  • Sedentary lifestyle: an inactive lifestyle
  • Diabetes Mellitus: Type 1 and Type 2 Diabetes are both risk factors.
  • Age: >45 in men and >55 in women.
  • Family History of Heart Disease: An early history of heart disease in families is a risk factor.

What Causes Heart Attacks:

  • Atherosclerosis: Build up of cholesterol on the walls of the coronary arteries leading to stiffening or hardening of the arteries.
    This plaque ruptures, causing the creation of a blood clot that prevents blood flow to the hearts muscle layer. Without blood, the heart does not receive oxygen, and the muscle starves to death.
  • Emboli:
    • A clot from the left ventricle or left atrium
    • Air Emboli
    • Endocarditis
  • Non-Clot Obstruction:
    • Trauma to the chest
    • Aortic Dissection

Signs and Symptoms of MI:

The signs of a heart attack are extremely important to note, early recognition may save someone’s life.

Chest pain (Angina) is the most common symptom in a heart attack. The chest pain is usually described as a “tightness or pressure,” located in the middle of the chest, and may present moving down the left arm or up to the jaw. In elderly patients, shortness of breath may be more prominent. It is notable that women and diabetics sometimes present differently, with nausea or vomiting a common sign. Some patients express a feeling of doom.

The signs of a heart attack are similar to panic attacks, GERD (Gastroesophageal Reflux Disease), or can be attributed to a musculoskeletal cause; thus it is important to keep myocardial infarction high on the list of possible diagnoses.

List of potential Signs of a Heart Attack:

Heart Attack Symptoms when to go to the Hospital

It’s important to note that you do not need all symptoms to be present. Any sign or symptom can be present alone or in combination. If you suspect you might be having a heart attack Immediately call 911 to be evaluated at a Hospital’s Emergency room.

  • Chest Pain and Discomfort
  • Arm Pain
  • Neck Pain
  • Jaw Pain
  • Epigastric Pain (Pain above the stomach)
  • Back Pain
  • Radiating Pain to Right or Left Arm and Shoulder
  • Chest heaviness or tightness
  • Lightheadedness
  • Nausea
  • Diaphoresis (Sweating)
  • Trouble Breathing (Dyspnea)


While the diagnosis can be noticed clinically, tests such as an EKG (Electrocardiogram) and blood tests to check for cardiac enzymes are usually employed to rule out other conditions.

On the EKG, findings can be defined as “STEMI” (ST-elevation Myocardial Infarction) or “Non-STEMI” based on elevations of segments of the EKG, and this defines the treatment in most cases.

Treatment Options for an MI:

First and foremost, in an out-of-hospital situation in which a patient is possibly experiencing myocardial infarction, the American HEart Assocation recomends that anaspirin should be given to the patient with instructions to chew it. The patient should be brought to a hospital immediately.

In Hospital treatment Options for Myocardial Infarctions:

Acronym MONA

  • Morphine, to reduce the pain and decrease blood return to the left ventricle.
  • Oxygen
  • Nitroglycerin sublingually to open the vessels, but it is important to make sure the patient is not taking erectile dysfunction medications.
  • Aspirin  to prevent further clotting

Other Treatments:

  • Beta-Blockers, which have been found to decrease mortality after a heart attack.
  • Statins, to stabilize any clots and prevent the formation of new ones.
  • Anticoagulation with heparin to prevent the formation of new clots.

Definitive Treatments for Myocardial Infarctions include:

Cardiac Catherization

Angioplasty Stenting

These treatments are surgical interventions in which the vessels are opened up manually, either with a balloon or a stent.

Updated on March 16, 2019

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