Cardiac diagnostic tests

1. Cardiac enzymes
Mrs. Srividhya.N

2. Introduction
Cardiac enzymes are markers formed in the blood.
The markers are normally present at all times, however they
are significantly elevated during a damage to heart muscle.

3. Definition
Cardiac biomarkers are protein molecules released into the
bloodstream from damaged heart muscle.

4. Types of cardiac markers
Troponin I and T
CK-MB
Lactic dehydrogenase (LDH)
Myoglobin
BNP
AST

5. Troponin
It is a contractile protein
Types Trop-I :
● Found in cardiac and skeletal muscle
● Rise -3 to 4 hrs
● Peak -24hrs
Trop T
● Found only in cardiac muscle
● Rise - 4 to 6 hrs
● Peak -18hrs

6. CPK /CK-MB
Creatinine Phospokinase
Highly specific for MI(CKMB)
Normal -15-100u/l
Rise - 4 -6 hrs
Peak 24hrs

7. Lactic Dehydrogenase (LDH)
Types LDH1 and LDH2
Normally LDH2 is greater than LDH1
In MI LDH1 is greater than LDH2
Rise 48 to 72 hrs
Normal Value- 100-200U/L

8. Myoglobin
It is a high sensitivity Muscle protein
Elevated in all muscle injury
Rise 1 -4 hrs
Peak 6-12 hrs

9. BNP
Brain type Natriuretic peptide
Excellent marker for ventricular function
Used especially in case of heart failure
Pro BNP Less than 125 pg/mL for patients aged 0-74 years. Less
than 450 pg/mL for patients aged 75-99 years.

10. AST
Aspartate transaminase
Elevated in MI
Normal value - 8-20U/L

11. Nurses responsibility
● Identify patient properly
● Check the doctor’s order
● Collect sample in sterile technique and sent to lab immediately as
it is an emergency test with proper label
● Inform the physician when the reports are ready without delay
● Make the patient comfortable and continuously monitor the
patient's hemodynamic status.