Let’s talk about myocardial infarction, which is the medical term for a heart attack. To break it down: “myo” refers to muscle, “cardio” relates to the heart, and “infarction” means death. So, myocardial infarction essentially means death of the heart muscle.

What causes this? The coronary arteries supply blood to the heart muscle and tissues, keeping the heart strong and pumping. Two main things can happen to cause a heart attack:

  1. A blockage, like a clot, in one of the coronary arteries.
  2. Severe vasoconstriction, where the blood vessels clamp down tightly.

Either way, blood flow is stopped, leading to a heart attack. Let’s get into some key terms and concepts.

Atherosclerosis and Arteriosclerosis

  • Atherosclerosis: This involves cholesterol deposits forming plaques that cause blockages. It’s essentially fat accumulating in the arteries.
  • Arteriosclerosis: This is the thickening and stiffening of the arteries, making them less elastic and less efficient at their job.

These conditions are primary risk factors for heart attacks.

Acute Coronary Syndrome (ACS)

ACS is a term you’ll hear a lot. It means something is happening to the coronary arteries right now, causing ischemia, a lack of oxygen to the heart muscle.

Acute Myocardial Infarction (AMI)

This means you’re having a heart attack right now, with heart muscle dying.

Ischemia, Injury, and Infarction

  • Ischemia is like the artery choking, with a lack of oxygen. EKG will show ST depression.
  • Injury progresses from ischemia. EKG will show ST elevation.
  • Infarction means death of the heart muscle cells. EKG will show a pathological Q wave. The Q wave is wide and approximately a ⅓ of the depth of the R wave.


  • Stable Angina: Chest pain that goes away with rest or nitroglycerin.
  • Unstable Angina: Persistent chest pain that doesn’t go away with rest or medication.
  • Prinzmetal Angina: A temporary vasospasm of the coronary artery, causing chest pain.

Heart Attack Classifications

  • STEMI: ST-Elevation Myocardial Infarction, identified by an EKG showing a heart attack, requiring immediate transport to a cath lab for a stent.
  • NSTEMI: Non-ST-Elevation Myocardial Infarction, where the EKG doesn’t show a heart attack, but blood work in the ER reveals it.
  • OMI: Occlusive Myocardial Infarction, an intermediate category based on EKG findings, patient symptoms, and history.

To summarize, here’s how we understand and treat heart attacks in four steps:

  1. What is it? A blockage or severe spasm of a coronary artery, leading to heart muscle death.
  2. Risk factors: Smoking, advanced age, diabetes, high cholesterol, high blood pressure, and family history.
  3. Signs and symptoms: Pressure, squeezing, chest pain, shortness of breath, nausea, vomiting, back pain, extreme fatigue, and syncope (fainting). Also, look for signs of heart failure, like fluid in the lungs or legs.
  4. Treatment: Aspirin, nitroglycerin, oxygen, pain medications, IV access, 12-lead EKG, cardiac monitoring, rapid transport to the hospital, and immediate cath lab intervention if necessary.

Always be ready to radio in to open the cath lab as soon as you suspect a heart attack. Ensure you understand these concepts thoroughly, as recognizing and responding to heart attacks swiftly and accurately can save lives.