Myocardial infarction (MI), biomarkers of myocardial infarction (MI), definition of biomarker, troponin I and troponin T, myoglobin, CK-MB, Creatine kinase (CK), best biomarker of myocardial infarction (MI), Laboratory investigations of myocardial infarction (MI), sepecific biomarker of, MI, sensitive, biomarker of MI, Normal range of biomarkers of MI, Elevation of biomarkers of myocardial infarction (MI) with time, Graph showing time course elevation of CK-MB, Myoglobin and Cardiac troponins, prabin kumar bam, chitwan medical college, bharatpur, nepal

1. Prabin Kumar Bam
MBBS,Chitwan Medical College
Nepal

3. LEARNING REFLECTIONS
To know the definition of biomarkers.
To understand the biomarkers of
myocardial infarction.

4. BIOMARKERS OF
MYOCARDIAL
INFARCTION

5.  Biomarker is any molecule, enzyme, hormone
or gene which is measured and evaluated as
an indicator of normal biological process or to
identify the presence of any disease of body.
 For example; body tempt. is a well known
biomarker for fever, cholesterols are
biomarkers for cardiovascular diseases.
 An ideal biomarker must be specific,
sensitive, prognostic, longer persisting,
reliable, quick & inexpensive.

6. BIOMARKERS FOR MI
Cardiac proteins
 Troponin I and Troponin T
 Myoglobin
Cardiac enzymes
 CK-MB

7. RANGE AND ELEVATION OF BIOMARKERS WITH
TIME
MARKER NORMAL
VALUES
ONSET PEAK RETURN
TO
NORMAL
CK-MB 5-
25IU/L
3-6
hrs.
18-24
hrs
36-72
hrs.
Myoglobi
n
0-
85ng/ml
1-4
hrs.
6-7
hrs.
24 hrs.
Troponin
I
4 hrs. 14-24
hrs.
5-10
days
Troponin
T
<0.01
ng/ml
6 hrs. 72 hrs. 10-14
days

8. TIME COURSE OF ELEVATION OF CK-MB &
TROPONINS IN BLOOD OF MI PATIENT

9. TROPONIN I & T
1. Troponin is a muscle protein which
helps in contraction. It consists of 3
subunits:
2. Troponin I (affinity for actin)
3. Troponin C (Calcium binding)
4. Troponin T ( Tropomyosin binding)

10. Troponin I & T are most sensitive
and specific biomarkers of MI at any
interval after the heart attack.
Troponins are specific for MI because
they are not increased in muscle injury
where as CK-MB is slightly raised in
some muscle injuries.

11. CREATINE KINASE / CK
It catalyzes the following reaction:
Creatine phosphate --------- Creatine
It has 3 iso-enzymes:

Iso-
enzyme
Tissue of
origin
% in blood
CK-MM Skeletal
muscle
80%
CK-MB Heart 5%
CK-BB Brain 1%

12.  Earlier, total serum CK was employed as a
biomarker of MI. But, nowadays only CK-
MB level is measured.
It is because total serum CK level is very
much elevated in diseases like muscular
dystrophy, fracture & cerebrovascular
accidents. So, it becomes quite unspecific
for determining MI.

13. CK-MB
 It is less specific than troponin I & T since
it is slightly elevated in skeletal muscle
injury also.
It is useful for early diagnosis and
diagnosis for re-infarction.
 However, it cannot be used in the case of
delayed admission (more than 2 days).

14. MYOGLOBIN
 It is a protein found in muscles and helps
in transportation of oxygen.
 It appears in blood earlier than other
markers i e; it has high sensitivity so it can
be used for early diagnosis.
 Since myoglobin is found in all 3 types of
muscles (skeletal, cardiac & smooth) and
in renal tissues it is not a specific
biomarker for MI.

15. RECOMMENDATIONS FOR USE OF
BIOMARKERS OF MI
 Recommended for all patients complaining
of chest pain (with ECG & clinical
examinations).
Sample: Plasma
 Sequence:
 Early marker- Myoglobin (appears in
blood early), but non-specific & doesn’t
persists for long time.

16. Definitive marker: Troponin (appears
in blood latter than Mb ) and is 100%
specific and stays longer. It is the first
choice.

17. REFERENCES
 Harper,s illustrated biochemistry
 Lippincott’s biochemistry
 Textbook of biochemistry by DM
Vasudevan
 Biochemistry by U. Satyanarayana

18. Thank you