Acute Myocardial Infarction Flashcards
What is Acute Coronary Syndrome? (ACS)
acute presentation of coronary artery disease – covers a spectrum of conditions, it is a provisional diagnosis
- dynamic stenosis
What is Chronic Stable Angina?
leads to fixed stenosis
demand led ischaemia
What is stenosis?
Narrowing of the heart valves
What are ACS?
Myocardial Infarction
Unstable Angina
Cardiac Death
What is the difference between ACS and Chronic Angina?
ACS = dynamic stenosis
Chronic Angina = fixed stenosis
What factors affect plaque rupture?
lipid content of plaque
thickness of fibrous plaque
sudden changes in intraluminal pressure or tone
bending and twisting of an artery during each heart contraction
plaque shape
mechanical injury
What are the assoicated symptoms of MIs?
nausea
vomiting
sweating
What ECG changes would you see in a STEMI?
ST elevation would be flat
T wave inversion
Always a Q wave
What does Left Bundle Branch block usually signify?
STEMI
What protein and enzyme tests can you do to diagnose a STEMI from a NSTEMI?
Enzyme CK – creatinine kinase (not used anymore)
Protein Marker – Tn Troponin: highly specific for cardiac muscle damage can detect tiny amounts of myocardial damage
What Antiplatelet drugs may be used in an MI?
Aspirin (300mg)
Clopidogrel (300mg)
Give examples of reperfusion surgery?
PCI and thrombolysis
What are the indications that a patient should undergo reperfusion surgery?
Chest pain suggestive of acute MI
ECH changes – ST elevation and Left Bundle Branch Block
No contraindications
What are the risks of thrombolysis?
Failure to re-perfuse
Haemorrhage – minor, major, intracranial haemorrhage
Hypersensitivity
If you cannot access PCI in 20 minutes what should you do?
Community thrombolysis
Outline the early STEMI treatment?
- analgesia – diamorphine IV
- anti–emetic – iv
- Aspirin and Clopididogrel – 300mg
- GTN if BP > 90mmHg
- Oxygen – if hypoxic
- Primary Angioplasty
- Thrombolysis – if angioplasty is not available
What are the complications of an acute MI?
- Death
- Arrhythmic complications
- Structural complications
- Functional complications
Give detail on the structural complications of an acute MI?
left ventricular aneurysm formation inflammation acute pericarditis dresslers syndrome mural thrombus
Give detail on the functional complications of an acute MI?
Acute ventricular failure (left, right and both)
chronic cardiac failure
cardiogenic shock
What is the KILLIP Classifications of in hospital heart failure mortality?
- No signs of heart failure
- Crepitations <50% lung fields
- Crepitations >50% lung fields
- Cardiogenic shock
Describe the 3 types of troponin? Which two show he microscopic zone of myocyte necrosis?
I – cardiac specific isoforms – in absence of Ca binds to actin, inhibits actin-myosin ATPase induced contraction
C – identical heart and skeletal muscle - binds to calcium
T – cardiac specific isoform – links troponin complex to tropomyosin, facilitates contraction
TnI and TnT
When is TnT also elevated?
CCF Hypertensive crisis renal failure pulmonary embolism sepsis stroke/TIA pericarditis myocarditis post arrhythmia
