Definition and Overview

Myocardial infarction, or heart attack in simpler terms, occurs when the heart has been deprived of oxygen usually due to a blockage on one of its arteries, causing the death of the cardiac muscle. Myocardial infarction is derived from the words myocardium, which is the heart’s muscle tissue, and infarc, which means the death of a localized tissue.

Heart disease is currently one of the leading causes of death in the United States. According to the Heart Foundation, at least 780,000 people died of cardiovascular disorder in 2011 while around 720,000 people have experienced heart attack for the first time. A heart attack also occurs every 34 seconds in the country.

The heart is central to the body’s circulatory system. It is the only organ that has its own type of muscle, called cardiac muscle, which is responsible for pumping volumes of blood 24 hours a day, 7 days a week.

The body has different types of blood vessels which main function is to distribute blood around the body. These include the arteries, which supply oxygenated blood from the heart to the rest of the body. The oxygen is necessary for vital metabolic functions of the cells. The heart itself also has arteries such as the aorta, which is the biggest of them all.

As the blood’s pathway, the arteries should remain open at all times. However, there are cases when they get blocked severely that they prevent the flow of blood to the body, including the heart. When the heart doesn’t receive the much-needed oxygen, the heart’s cells, which make up the muscles, begin to die (necrosis). The person can then go through cardiac arrest, where the heart stops pumping blood, as well as experience stroke, aneurysm (weakening of the arteries that can lead to rupture), heart failure, and blood clot formation.

Causes of Condition

  • Atherosclerosis – This is a condition characterized by the narrowing of the arteries due to plaque buildup and is normally associated with weakened or damaged arteries. Substances such as cholesterol can accumulate, and platelets try to repair the damage by forming a blood clot. This blood clot can potentially block the artery, or it can rupture, spilling the substances into the bloodstream and blocking blood flow.

  • Spasm of the artery – This refers to the tightening of the arteries, including those that do not experience stenosis (narrowing). This is less common and typically caused by high levels of emotional and physical stress, smoking, and intake of illicit drugs like cocaine. Spasm can also happen when a person is exposed to frigid weather or very cold temperatures.

  • Spontaneous coronary artery dissection (SCAD) – This involves the tearing of one of the blood vessels of the heart, in this case, the arteries. This may then lead to a complete blockage and cardiac ischemia, wherein the heart is totally deprived of oxygen. Since this occurs suddenly or spontaneously, it is treated as an emergency situation, but it rarely occurs.

Other factors that can also increase the risk of a heart attack include the following:

  • Diabetes
  • High blood pressure or hypertension
  • Obesity
  • Age
  • Gender (heart attack is more common among men than women)
  • Heredity and family history
  • High levels of LDL (low-density lipoprotein) cholesterol and triglycerides
  • Sedentary lifestyle
  • Smoking and alcohol
  • Stress

Key Symptoms

One of the classic symptoms of a heart attack is chest pain (angina). It is often described as a feeling of tightening or discomfort of the chest. The major difference between a heart attack and a regular chest pain is that the latter subsides—the former doesn’t.

Other symptoms include:

  • Fatigue
  • Breathlessness or difficulty in breathing
  • Stomach pain
  • Profuse sweating
  • Nausea
  • Lightheadedness
  • Pain in the upper torso such as the neck or jaw
  • Pain in the arms and back


It’s essential to note that although men and women can share these symptoms, there are differences. For example, women tend to experience them in a subtler manner, which may prevent them from immediately seeking the necessary help.

Who to See and Types of Treatments Available

A cardiologist is an expert in any heart-related problems. To diagnose the condition, the patient is advised to undergo different tests, such as the following:

  • Electrocardiogram (ECG), which monitors the heart’s electrical activity
  • Blood tests - Studies show that when the heart is damaged, it releases C-reactive proteins into the bloodstream.
  • Angiography, an X-ray imaging exam that uses a contrast dye to locate the artery’s problematic area.


Regardless of the condition’s severity, all heart attacks are treated as an emergency. This is because it takes only around 30 minutes for the organ’s cells to die.

Immediate treatment includes the use of aspirin, a common medication that prevents the formation of blood clots, as well as nitroglycerin, which eases the heart’s workload while the blood flow is being improved.

The doctor may also provide some extra oxygen through a nasal cannula or by performing a procedure called transtracheal oxygen therapy, where an incision is made in the trachea, a tube is attached, and oxygen is delivered through the tube.

For the long term, the cardiologist may carry out percutaneous coronary intervention (PCI), also known as angioplasty, which is usually accompanied by stenting. This procedure requires the insertion of a balloon catheter into the blocked artery. The balloon is inflated to push the plaque toward the arterial walls. Meanwhile, a stent is added to keep the arteries open. Drugs such as ACE inhibitors, anticoagulants, and statins may also be prescribed.

Many risk factors are modifiable, and a lifestyle change is necessary to succeed in living a healthy life after an episode of a heart attack. These include:

  • Weight management
  • Stress management
  • Proper nutrition
  • Quitting alcohol and smoking
  • Increasing physical activity


People with existing conditions like diabetes should go through regular heart screenings as they may be prone to “silent ischemia” or asymptomatic heart attack.
References:

  • Amsterdam EA, Wenger NK, Brindis RG, Casey DE Jr, Ganiats TG, Holmes DR Jr, Jaffe AS, Jneid H, Kelly RF, Kontos MC, Levine GN, Liebson PR, Mukherjee D, Peterson ED, Sabatine MS, Smalling RW, Zieman SJ. 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;64:e139-228. PMID: 25260718 www.ncbi.nlm.nih.gov/pubmed/25260718.

  • Anderson JL. ST segment elevation acute myocardial infarction and complications of myocardial infarction. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 73.

  • Giugliano RP, Cannon CP, Braunwald E. Unstable angina and non-ST elevation myocardial infarction In: Mann DL, Zipes DP, Libby P, et al. eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 10th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 53.

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