1. Cardiac enzymes. 2 – Non enzyme proteins The Troponins
Dr Muhammad Ramzan

2. Cardiac Troponin – the definition A muscle protein
Cardiac Troponins are the regulatory proteins that control the Calcium mediated interactions B/W Actin and Myosin
Cardiac Troponin consists of 2 subunits and include Troponin I (cTnI) and Troponin T (cTnT))
– Webster.com – J Clin Pathol.2004

3. Cardiac Troponins (cTn) – the background non enzyme proteins
Troponin is a muscle protein of 3 subunits (cTnI, cTnT and cTnC) and a part of native Tropomycin (Tc is for Ca binding .SK muscles)
Cardiac Troponin are low/absent in smooth muscles
Have different AA sequence for their detection through Monoclonal antibody assay
Troponins are released into the plasma in response to cardiac (MI) and skeletal muscle damage
Alpert et al,2000

4. Cardiac Troponins – the properties bound and free floating
cTn are coded by specific genes and are unique to Cardiac muscles
Have shorter half life of 90 min. appears 3-4 hours after symptoms
Majority of the cTn are bound to myofilaments but remainder is free floating in the cytoplasm
This is in comparison to the CKMB which is fully Cytosolic
cTn levels are normally too low to be detected in plasma
Have no base line
Alpert et al,2000 (Tunstall- Paedo et al. 1994) –

5. Cardiac Troponins – 2 Peaks and clearance
cTn has 2 peaks – an early and late
Early Peak / Cytosolic pool of cTn is released first in the blood
Late peak / level is maintained by the degradation of myofilaments
cTn has no base line with slow clearance (7- 14 days),
to the CKMB which get cleared in 3- 4 days
Neumayr et al,2001

6. Elevation of Troponins in MI

7. Release of cTn – the mechanism injury to the car. Cell membrane
Cardiac injury occurs when membrane of normal cardiac myocyte is damaged ( Ischaemic cell death)
It results in the loss of intracellular and structural proteins like Troponins; CK, LDH,blood, and Myoglobin into :
Extra cellular space - the biomarkers
The subsequent release is maintained by the degradation of the Actin and Myosin filaments

8. Injury to Card. Cell - Release of cTn

9. Cardiac Troponin – 2 Types
There are 2 types of Troponins, present in cardiac muscles with certain differences
Cardiac Troponin T - cTnT
Cardiac Troponin I - cTnI
Major cause for their elevation is CAD/ MI

10. Elevated cTn – Non CAD conditions1
Elevated levels of cTn are also found in non coronary artery (CAD) related conditions Like:
Critically ill patients with non CAD – 50%
Tachycardia %
Pancreatitis/heavy exercise %
Heart failure %
Bakshi et al; 2002 – Korff et al;2006

11. Diagnostic value of cTn
Detection and monitoring of the cTn is the new standard in the differential diagnosis of the of the :
Unstable angina and non ST elevation MI in ACS patients
It is also significant in the following conditions:
Acute MI; Myocardial re- infarction, post procedural MI and 2
diagnosis of MI after non cardiac surgery
Braunwald et al;2000 -

12. Cardiac biomarkers - significance the features
These are the molecules released into blood after myocardial damage and enhance the ability of the clinician:
to manage the patient after chest pain (blood, urine and tissues)
The important cardiac biomarkers are :
The Typical rise and gradual fall in cTn or :
A more rapid rise and fall in CKMB and others
Rama Chandran Vasan ;2006

13. Myocardial infarction (MI) - the definition
It is the death of an area of myocardium as a result of sudden and complete obstruction of blood supply
Most common cause of the MI is the occlusion of the coronary artery or one of its branches
MI is characterized by the history; Physical examination,ECG, cardiac imaging and cardiac biomarkers

14. Criteria for MI – 2 Classes Expert consensus document
Criteria for the diagnosis of MI is divided into 2 according to the Expert Consensus Document
This document was agreed upon by the experts from the :
European Society of Cardiology (ESC), American College of Cardiology (ACC) and American Heart Association (AHA)
1. Criteria for an acute, evolving or recent MI
2. Criteria for the established MI

15. Diagnosis of MI - acute /recent / evolving MI. A. one of the biomarkers
Criteria for acute, evolving or recent MI
Either one of the following criteria, satisfies the diagnosis for acute/evolving/recent MI
1. Cardiac Biomarkers:
Typical rise and gradual fall of cTn or
More rapid rise and fall (CKMB)
(one of cardiac bio markers- cTn – CKMB )

16. Diagnosis of MI . Acute/recent. B ECG changes/symptoms
At least one of the followings:
1.Ischaemia symptoms – severe pain/pressure in the chest
2. Development of pathological Q waves on ECG,
3. ECG changes indicative of Ischaemia like ST segment elevation or depression
4.Coronary artery intervention (Coronary angioplasty)
J Am Coll Cardiol Sep;36(3): –ESC/ACC/AHA

17. Normal Electrocardiogram - ECG

18. Pathological Q wave

19. MI – ST segment elevation

20. MI- ST segment depression

21. Diagnosis of MI - Established MI 2 ECG and structural heart changes
Criteria for the established MI
Any one of the following criteria satisfies the diagnosis for the established MI
1.Patient may or may not remember the symptoms
2.. Development of new pathological Q waves on serial ECG 2
3.Biochemical markers of MI may have normalized-with time
4. Pathological findings of a healed/healing MI (Echo .Imaging) 3
(1. New patho.Q wave 2. echo +imaging of healed infarcts)

22. Difference B/W Cardiac Troponins (cTn) and Creatine Kinase (CK- CKMB)
Serial NO
Cardiac Troponins
CKMB 1
Are non enzyme proteins
Are enzyme proteins 2
Are specific to cardiac myosites
Also present in skeletal muscles 3
Normal serum levels are too low to be detected, has no base line
Normal serum levels are detected – has base line 4
Majority is bound to cardiac myofilaments
Majority is unbound and fully Cytosolic 5
Rapid rise and gradual fall with
Late clearance
Rapid rise and fall in MI
early clearance 6
Elevated levels Predicts the adverse out come in CAD
No such property 7
Predicts the infarct size
Do not predict

23. Cardiac biomarkers- the time table