acute myocardial infarction

Question 1

pathophysiology

Answer 1

usually due to thrombotic occlusion of coronary vessel caused by rupture of plaque - ischaemia

or ischaemia caused by increased oxygen demand eg HTN or decreased supply eg coronary artery spasm, embolism, arrythmia, hypotension

Question 2

epidemiology

Answer 2

2. 46% in men

0. 87% in women

Question 3

clinical presentation: signs

Answer 3

dizziness
nausea 
sob
sweating 
no sign at all! 
chest pain

Question 4

clinical presentation: symptoms

Answer 4

chest pain - radiates to left arm 
sob
sweating
nausea
vomiting 
fatigue

Question 5

characteristic ECG changes for MI

Answer 5

complete coronary occlusion : ST elevation -> Q waves (at 3days)

partial coronary occlusion : ST depression, T wave inversion, may be normal -> No Q waves (at 3days)

Question 6

other diagnostic aids for MI

Answer 6

blood tests - check troponin, immediate point of care test

check Hb, kidney function, cholesterol

Question 7

classification

Answer 7

type 1 : spontaneous MI
type 2 : MI secondary to ischaemia 
type 3 : post-mortem
type 4a : percutaneous coronary intervention
type 4b : stent thrombosis
type 5 :  bypass

Question 8

type 1

Answer 8

spontaneous and the ‘typical’ MI

atherosclerosis originates from damage to endothelium and build-up of cholesterol

Question 9

type 2

Answer 9

secondary to ischaemia
common event in hosp where patients with SCAD +/- previous coronary intervention are unwell and put additional stress on heart that’s not normally not present
sufficient imbalance between supply of blood and demand for blood then myocardium becomes ischaemic without plaque rupture event

Question 10

type 3

Answer 10

post-mortem

Question 11

type 4

Answer 11

related to percutaneous coronary intervention - ie caused by angioplasty procedure blocking side branch or damaging main coronary artery -> ischaemia

related to stent thrombosis
if patients stop anti-platelets early post-angioplasty or continue to smoke, stents can occlude (STEMI - if complete sudden thrombosis or NSTEMI if gradual re-stenosis over time)

Question 12

type 5

Answer 12

related to bypass graft (CABG) operation

Question 13

STEMI

Question 14

non-STEMI

Question 15

diagnosis

Answer 15

detection of cardiac cell death : +ve cardiac biomarkers
AND one of :
symptoms of ischaemia
new ECG changes
evidence of coronary problem on coronary angiogram or autopsy
evidence of new cardiac damage on another test

Question 16

aetiology

Answer 16

main = coronary heart disease

Question 17

coronary heart disease

Answer 17

major blood vessels that supply heart are occluded with fatty deposits of cholesterol, known as plaques
before a heart attack, 1 bursts, causing a blood clot to develop at site of rupture - may block supply of blood to heart -> ischaemia -> heart attack

Question 18

treatment

Answer 18

GTN spray (glycerol trinitrate)
vasodilator
sub-lingual or as IV infusion

opiates (eg morphine)

• relieve anxiety
• venodilate - haemodynamic benefits ?

Question 19

thrombolysis

Answer 19

very strong blood thinning med
given in back of ambulance
often prompt transfer to cardiac centre with cath lab

Question 20

risks of thrombolysis

Answer 20

bleeding

contraindications = previous stroke, previous intracranial bleed

caution = recent surgery, on warfarin, severe HTN

Question 21

reperfusion therapy

Answer 21

mechanical = cath lab with balloons and stents = primary pci

pharmacological = strong blood thinner

Question 22

risk factors

Answer 22

male
age
known CV disease
HTN
high cholesterol
diabetes
smoking
FH

Question 23

other causes of chest pain

Answer 23

pulmonary = PE, pneumonia, pleurisy, pneumothorax

emotional = anxiety/depression

GI = ulcer disease, hiatal hernia, pancreatitis

MSK = costochondritis, arthritis, muscular spasm, bone tumour

Question 24

coronary disease is ___ most common cause of ____ in scotland

Answer 24

2nd

death