Cardiac Biomarkers

Question 1

Muscle types

Answer 1

• Skeletal = striated
• Cardiac = striated & branched
• Smooth = non-striated

Question 2

Creatine kinase

Answer 2

An enzyme that catalyses the reversible reaction converting creatine into phosphocreatine

Phosphocreatine is a high energy molecule that can be used when there is a high ATP requirement

Question 3

Isoforms of creatine kinase

Answer 3

BB = found in the brain 
MB = found in the myocardium 
MM = found in skeletal muscle & the myocardium

Question 4

Aspartate aminotransferase (AST)

Answer 4

An enzyme that catalyses the reaction between glutamate and oxaloacetate into a-ketoglutarate

Found in both the liver and myocardium

Question 5

Lactate dehydrogenase (LD)

Answer 5

An enzyme that catalyses the conversion of lactate to pyruvate

Two subunits; the H subunit catalyses the forward reaction & the M subunit catalyses the reverse

The LD-1 isoform is found in the heart

Question 6

Troponins

Answer 6

Play a role in muscle contraction

There are 3 isotypes; T, I & C

Only T & I are specific to the myocardium

Question 7

Atherosclerosis

Answer 7

An accumulation of fatty plaques in arteries

May cause narrowing of the artery and subsequently result in a heart attack or angina

Question 8

Treating a heart attack

Answer 8

A heart attack requires hospitalisation

Blood flow must be restored to the myocardium, this can be carried out by angioplasty or using clot-eliminating drugs

Question 9

Biomarkers for a myocardial infarction

Answer 9

AST = increases 
LD = increases 
CK = increases 
Myoglobin = increases in the serum 
Troponins = increases