Myocardial Infarction

Question 1

Define myocardial infarction

Answer 1

Myocardial infarction (MI), commonly referred to as a heart attack, occurs when there is a prolonged lack of blood flow to a part of the heart muscle, leading to tissue damage.

Question 2

Define acute coronary syndrome

Answer 2

Acute coronary syndrome (ACS) is a term used to describe a range of conditions that involve sudden, reduced blood flow to the heart, including unstable angina, non-ST segment elevation MI (NSTEMI), and ST-segment elevation MI (STEMI).

Question 3

What is Ischaemia?

Answer 3

Ischemia refers to a reduced blood flow to a part of the heart muscle, which can cause symptoms such as chest pain or discomfort, shortness of breath, and fatigue.

Question 4

Angina

Answer 4

Angina is a type of chest pain or discomfort that occurs when the heart muscle does not receive enough oxygen-rich blood.
Angina can be stable or unstable, depending on whether it occurs predictably with exertion or at rest, respectively.

Question 5

What are some risk factors of cardiac disease?

Answer 5

smoking, high blood pressure, high cholesterol, diabetes, and family history of heart disease

Question 6

Name two cardiac markers of damage

Answer 6

Creatinine kinase
Troponin

Question 7

Define POCT in A&E setting

Answer 7

Point-of-care testing (POCT) devices are portable, easy-to-use diagnostic tests that can be performed at the bedside or in the accident and emergency setting.
POCT devices can be used to rapidly diagnose conditions such as MI, by measuring cardiac markers such as troponin.
The use of POCT devices in the accident and emergency setting can help to facilitate rapid diagnosis and treatment of acute coronary events, leading to improved patient outcomes.

Question 8

WHO classification of myocardial infarction?(3)

Answer 8

2/3 must be met
Ischaemic symptoms
ECG changes
Increased serum biomarkers

Question 9

Clinical features of MI

Answer 9

Chest pain
Breathlessness
Nausea and vomiting

Question 10

Unstable angina - criteria

Answer 10

Caused by ischaemia (reduced blood supply)
No muscle death
No ECG changes
No elevation of cardiac markers

Question 11

Name two commonly used cardiac biomarkers

Answer 11

Troponin
Creatinine kinase

Question 12

5 factors for an ideal biomarker diagnostically

Answer 12

1. High sensitivity
2. High specificity
3. Rapid release to detectable concentration
4. Long t1/2
5. Correlate efficiently with extent of damage

Question 13

3 factors that make an ideal biomarker for analysis

Answer 13

1. High sensitivity
2. High specificity
3. Easy, inexpensive and rapid to test

Question 14

Two enzyme cardiac markers

Answer 14

Creatinine kinase
Lactic dehydrogenase

Question 15

3 prognostic markers and risk stratification markers for cardiac disease

Answer 15

CRP
MPO, homocysteine
Troponin

Question 16

Troponin

Answer 16

Integral for muscle contraction
Present in cardiac and skeletal muscle
Types of TPN differ
Complex of three proteins

Question 17

Some _________ is present in skeletal muscle

Answer 17

Troponin T

Question 18

Which two Troponin are used as cardiac markers?

Answer 18

Tpn I (more specificity) and Tpn T (levels can persist for up to 10 days after MI)

Question 19

Troponin I

Answer 19

3 homologous isoforms
Highly bound to the tropo-myosin complex in the sarcomere

Question 20

Troponin T

Answer 20

Cardiac Troponin T has 4 isoforms
Foetal skeletal muscle: + cardiac Troponin isoform
Muscle injury, myopathy, renal failure: re expression of cardiac Troponin T in muscles
Possible false positives in renal failure

Question 21

3 preanalytical factors that effect Troponin

Answer 21

Fibrin clots
Rheumatoid factor
Elevated ALP

Question 22

Creatinine kinase

Answer 22

Mainly 3 isoforms part from mitochondrial form

CKMM - skeletal muscle
CKMB - cardiac muscle
CKBB - Brain

Question 23

How is creatinine kinase measured?

Answer 23

Photometry

Question 24

Total CK includes:

Answer 24

CKMM and CKMB
CKBB is not normally detected

Total CK can be raised in non-cardiac causes

Useful in diagnosing re-infarction

Question 25

Heart-type fatty acid binding protein

Answer 25

Small cytoplasmic protein
Sensitive early marker
Prognostic marker