Block 2 Case 8 Answers - IHD

A man presents with crushing chest pain that is present at rest. He previously was able to releave his pain with rest but now the pain is occurring when he is sitting at his desk and work. It is escalating in frequency and   intensity. He presents to the ER concerned that he is having an MI. His initial troponin level is negative but when it is retested two hours later it is found to be elevated.

If a biopsy of his heart looked like the following slide -how long would you estimate the ischemia had been occurring?

• 12-24: Note Caugulation necrosis, few PMN, edema, hemorrhage

If a biopsy of his heart was taken in a different section it would show the following: what does this tell you?

• the scar tissue tells us that he has had a prior heart attack.

How is stable angina vs unstable angina treated? 

• stable angina will improve with rest and vasodilators
• unstable/crescendo is a sign of a complicated plaque and requires anti-coagulation

Name 3 things that can decrease risk of IHD:

• regular excercise
• folate
• ETOH/red wine
• high HDL
• estrogen
• antioxidants

IHD is caused by an inbalance between oxygen supply and demand of the myocardium. What three things does oxygen demand depend on?

• contractilty: decrease with rest, betablockers, calcium-channel blockers
• Heart rate
• Ventricular wall tension - ex: LVH

Name two reasons why there oxygen demands would not be met despite adeuqate blood-flow:

• carbon monoxide
• anemia

If there is a fixed obstruction due to atherosclerosis of a coronary artery which artery is most likley involved?

LAD>RCA>L circ

Name which artery is responsible for supplying the following areas:

• anterior left ventricle - LAD
• posterior left ventricle - RCA
• andterior 2/3 septum - LAD
• post 2/3 septum - RCA
• lateral left ventricle -  L. circumflex

Time	Gross	Micro
0-6	None	None; wavy fibers (4hrs)	normal myocardium
6-12 hr	None / mottling	Few “wavy” fibers	note: wavy fibers, the nuclei are still present, no inflammatory cells yet
12-24hr	Pallor/mottling	Caugulation necrosis, few PMN, edema, hemorrhage
24-72	Pallor	Coagulative necrosis, dense PMN infiltrate, cross striation = contraction bands
3-7days	Pallor	Macrophages! Granulation tissue at the periphery
7-10 days	Yellow-gray center	Macrophages, granulation	granulation tissue most prominent week2-3.
10-21d	gray	Increasing fibrosis	collagen deposition increases to form a scar
6wk-1yr	Scar reaches full tensile strength at 1 yr	fibrosis	note: images from http://library.med.utah.edu/WebPath/CVHTML/CV022.html