(P4) Cardiac: Myocardial infarction

Question 1

Myocardial infarction

Define:

Answer 1

Defined as necrosis of the heart muscle

resulting from ischemia

The most important form of ischemic heart disease (IHS)

One of the leading causes of death in the world

Question 2

Myocardial infarction

Caused by what?

Answer 2

Caused by coronary artery occlusion usually due to acute thrombosis on a surface of unstable atheromatous plaque

Question 3

Myocardial Infarction

is

characterized by what?

Answer 3

Characterized by

myocardial coagulative necrosis

Question 4

Myocardial infarction

What are its patterns: (2)

Answer 4

– Transmural – involve entire wall of the heart muscle

– Subendocardial ‐ affects the inner 1/3 of the left ventricule usually as a consequence of general hypoperfusion (heart failure, haemorrhagic shock)

Question 5

Myocardial infarction

localizaton:

Answer 5

– Left anterior descending (LAD) branch > right coronary artery (RCA) > left circumflex (LCx) branch

Question 6

Myocardial infarction

Macro:

Answer 6

• 1. First abnormalities visible after 4‐12 hours*
• 2. After 18‐24 hrs – infarcted tissue changes color‐ grossly is discretely pale*
• 3. During first week: lesions are more defined and yellow in color*
• 4. After week: infarcted area is yellow and surrounded by congested red border*
• 5. After few weeks there is grey‐white scar, which is well developed after 3‐6 months*