MI Flashcards
What is chronic stable angina?
Fixed stenosis
Demand led ischaemia
Predictable
Safe
What is an acute coronary syndrome?
Acute presentation of coronary artery disease (is a provisional diagnosis)
What are the 2 types of acute MI?
STEMI
NSTEMI
What is the pathogens is of acute coronary syndromes?
Normal Fatty streak Atherosclerotic plaque Fibrous plaque Plaque rupture/fissure & thrombosis
Risk factors for MI
Smoking Alcohol stress Hypertension Drug abuse High cholestrol Age Obesity Gender Family History
Factors that can cause an atheroma plaque to rupture?
Sudden changes in infra luminal pressure or tone
Bending & twisting of an artery during heart contraction
Lipid content of plaque
Thickness of fibrous cap
Plaque shape
Mechanical injury
What are the stages of the platelet cascade?
Initiation (vascular damage) Adhesion Activation Release of activators Surface receptors Amplification of platelet activation Activation triggers inflammatory cascade
Clinical presentation of MI
Severe crushing central chest pain Radiating to jaw and arms (esp. left) Similar to angina but more severe, prolonged Not relieved by GTN Sweating Nausea Vomiting
What changes does a STEMI cause in an ECG?
ST elevation (first few hours) Q wave formation and T wave inversion (first day)
What leads does a inferior STEMI affect?
II
II
aVF
What leads does an anterior MI affect?
V1 - V6
What leads does anteroseptal MI affect?
V1 - V4
What leads does am anterolateral MI affect?
I
aVL
V1 - V6
Investigations to diagnose MI
CK
troponin T
How does an MI affect CK?
Peaks in 24 hours
Also in skeletal muscle and brain
How does an MI affect troponin T?
Highly specific for muscle damage
Raised after MI
Early treatment of STEMI
Analgesia - diamorphine IV Anti-ometic IV Aspirin 300mg and clopidogrel 300mg GTN - if BP > 90 mmHg Oxygen if hypnosis Primary angioplasty Thrombolysis (if angioplasty not available within 90 mins)
What are the indications for reperfusion therapy?
Thrombolysis or PCI
Chest pain suggestive of acute MI
ECG changes (ST elevation - NEW LBB)
No contraindications
What are the risks of thrombolytic therapy?
Failure to re-perfuse
Haemorrhage
Hypersensitivity
Complications of an MI
Death
Arrhythmic complications
Structural complications
Functional complications
Most common arrhthymic complication of an MI
Ventricular Fibrillation
Structural complications of an MI
Cardiac rupture Ventricular septal defect Mitral valve regurgitation Left ventricular aneurysm Inflammation Acute pericarditis Dressler's syndrome
Functional complications of an MI
Acute ventricular failure (left, right, both)
Chronic cardiac failure
Cardiogenic shock
What are the 4 phases of cardiac rehab?
Phase 1 - in-patient
Phase 2 - early post discharge period
Phase 3 - structured exercise programme (hospital based)
Phase 4 - long term maintenance of new lifestyle (community based)
