acute myocardial infarction

Question 1

what does the term acute coronary syndrome cover?

Answer 1

• unstable angina
• acute non STEMI
• STEMI

Question 2

which factors affect the rupture of a plaque?

Answer 2

• lipid content of plaque
• thickness of fibrous cap
• sudden changes in intra luminal pressure or tone
• bending and twisting of an artery during each heart contraction
• plaque shape
• mechanical injury

Question 3

what will the history of acute coronary syndrome be?

Answer 3

• severe crushing central chest pain
• radiating to jaw and arms, esp the left
• similar to angina but more severe, prolonged and not relieved by GTN
• associated with sweating nausea and often vomiting

Question 4

what are the differences in presentation from angina vs MI?

Answer 4

10 mins vs 30+ mins
on exertion vs at rest
usual pain vs more severe
relief vs no effect of GTN
no assoc symptoms vs sweating, nausea, vomiting

Question 5

what are the ST changes in acute STEMI?

Answer 5

• > 1mm ST elevtaion in 2 adjacent limb leads
  2mm ST elevatino in at least 2 contiguous precoridal leads
• new onset bundle branch block

Question 6

what are the evolving ECG changes of acute MI?

Answer 6

• ST elevation in first few hours

- Q wave formation and T Wave inversion - first day

Question 7

what cardiac enzymes and protein markers are used? NSTEMI

Answer 7

• CK creatinine kinase = peaks in 24 hours, also in skeletal muscles and brain
• Tn troponin - highly specific for cardiac muscle damage, can detect tiny amounts of myocardial necrosis

Question 8

what are the early treatment drugs used to damp down platelet reaction in STEMI?

Answer 8

• aspirin and clopidogrel

- used in order to reduce chance of vascular blockage

Question 9

what are the indications for perfusion therapy? NSTEMI(thrombolysis or PCI)

Answer 9

1. chest pain suggestive of acute myocardial infarction (> 20 mins <12 hours)
2. ECG changes - acute ST elevation, new LBBB
3. no contraindications

Question 10

what are the risks of thrombolytic therapy? - early hazard NSTEMI

Answer 10

• failure to re-perfuse
• haemorrhage
• hypersensitivity

Question 11

what are the early treatments of STMEI?

Answer 11

• analgesia - diamorphine IV
• anti-emetic - IV
• aspiriin - 300 mg and clopidogrel 300 mg
• GTN - if BP > 90 mmHg
• oxygen - if hypoxic
• primary angioplasty
• thrombolysis - if angioplasty not available within 90 minutes

Question 12

what are structural complications? NSTEMI

Answer 12

• cardiac rupture
• ventricular septal defect
• mitral valve regurgitation
• left ventricular aneurysm formation
• mural thrombus +- systemic emboli
• inflammation
• acute pericarditis
• dresslers syndrome

Question 13

what are functional complications? NSTEMI

Answer 13

• acute ventricular failure
• chronic cardiac failure
• cardiogenic shock

Question 14

why is troponin used?

Answer 14

• used to identify high risk NSTEMI patients

Question 15

when do the extrinsic and intrinsic pathways join together?

Answer 15

• factor 10