Myocardial Ischemia

Question 1

What’s the underlying mechanism of a myocardial infarction?

Answer 1

The complete blockage of a coronary artery caused by a rupture of an atherosclerotic plaque

Question 2

What is the basis for injury curent associated with myocardial ischemia?

Answer 2

Measures the potential difference between intracellular compartments of the ischemic and nonischemic cells at any part of the cardiac cycle

NOTE: The injured tissue has a negative voltage compared to the central part of the body.

Question 3

What three areas can be identified in a myocardial infarction?

Answer 3

• Area most severly damaged, heals with scar of conenctive tissue
  
  • Area that surrounds this area is called the area of injury
• Ischaemic area
  
  • Between area of injury and nromal muscle tissue

Question 4

Ischaemia alters only ___________ (repolarization/depolarization)

Answer 4

Repolarization

• Results in an abnormal T wave, typically negative pointed

Question 5

During diastole, where does the injury current come from and why?

Answer 5

From the injury area because it is more depolarized thatn the normal muscle

Question 6

During systole, where does the injury current come from and why?

Answer 6

From normal tissue because it is more depolarized than the injury area

Question 7

The injury current results in a shift of the _______ segment.

Answer 7

ST