Myocardial Infarction Flashcards
Define myocardial infarction
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.
Define acute coronary syndrome
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).
What is Ischaemia?
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.
Angina
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.
What are some risk factors of cardiac disease?
smoking, high blood pressure, high cholesterol, diabetes, and family history of heart disease
Name two cardiac markers of damage
Creatinine kinase
Troponin
Define POCT in A&E setting
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.
WHO classification of myocardial infarction?(3)
2/3 must be met
Ischaemic symptoms
ECG changes
Increased serum biomarkers
Clinical features of MI
Chest pain
Breathlessness
Nausea and vomiting
Unstable angina - criteria
Caused by ischaemia (reduced blood supply)
No muscle death
No ECG changes
No elevation of cardiac markers
Name two commonly used cardiac biomarkers
Troponin
Creatinine kinase
5 factors for an ideal biomarker diagnostically
- High sensitivity
- High specificity
- Rapid release to detectable concentration
- Long t1/2
- Correlate efficiently with extent of damage
3 factors that make an ideal biomarker for analysis
- High sensitivity
- High specificity
- Easy, inexpensive and rapid to test
Two enzyme cardiac markers
Creatinine kinase
Lactic dehydrogenase
3 prognostic markers and risk stratification markers for cardiac disease
CRP
MPO, homocysteine
Troponin
Troponin
Integral for muscle contraction
Present in cardiac and skeletal muscle
Types of TPN differ
Complex of three proteins
Some _________ is present in skeletal muscle
Troponin T
Which two Troponin are used as cardiac markers?
Tpn I (more specificity) and Tpn T (levels can persist for up to 10 days after MI)
Troponin I
3 homologous isoforms
Highly bound to the tropo-myosin complex in the sarcomere
Troponin T
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
3 preanalytical factors that effect Troponin
Fibrin clots
Rheumatoid factor
Elevated ALP
Creatinine kinase
Mainly 3 isoforms part from mitochondrial form
CKMM - skeletal muscle
CKMB - cardiac muscle
CKBB - Brain
How is creatinine kinase measured?
Photometry
Total CK includes:
CKMM and CKMB
CKBB is not normally detected
Total CK can be raised in non-cardiac causes
Useful in diagnosing re-infarction
