Acute Coronary syndromes Flashcards
How is it defined?
Partially or totally occluded coronary artery which leads to myocardial ischaemia.
Different types of A.C.S.
- unstable angina
- STEMI
- NSTEMI
Defining characters of a STEMI?
- ST elevation
- Q waves
- hyper-acute T waves
- full myocardial cell thickness damage
- transmural MI
- complete occlusion of Coronary artery
Defining characters of an NSTEMI?
- no ST elevation
- Q wave NSTEMI or nQ wave NSTEMI
- ST depression/ T wave inversion
- Sub-endocardium MI
- Partial thickness damage
- partial occlusion of coronary artery
Diagnosis of an A.C.S.
- Chest pain: if it lasts more than 20 mins it is an A.C.S.
- ECG: ST elevation indicates STEMI
- troponin level increase indicates NSTEMI
- if no increase in troponin level- unstable angina
What could an increase in troponin also be a sign of
Pulmonary embolism
sepsis
renal failure
sub-arachnoid haemmorage
Classification of an MI
TYPE 1: sudden MI related to primary coronary artery event e.g. rupture TYPE 2: 02 demand mismatch Due to ischaemia but not C.A. event TYPE 3: Sudden cardiac death related to thrombus confirmed but after death TYPE 4: related to PCI or angioplasty TYPE 5: related to CABG
Aetiology of A.C.S.
- coronary artery atherosclerosis
- coronary artery inflammation
- vasospasm; cocaine, chemotherapy
- radiotherapy can cause fibrosis/stenosis
- embolism/thrombus down C.A.
Different types of M.I. and what vessels are they related?
inferior: R.C.A
anterior: left anterior descending
lateral : circumflex
posterior:
-difficult to detect because no posterior leads
-usually related to R.C.A.
-will show opposite events on ECG in opposite areas e.g. V1-V2
Symptoms
CHEST PAIN:
- lasting more than 20 minutes at rest
- retro-sternal
- radiating up jaw, neck, left arm
In diabetics, elderly, reduced sensitivity to pain:
- SOB
- nausea
- Syncope
- Sweatiness
When does it cause major damage?
-when proximal to the heart or when it affects a vessel which supplies major area of the heart
Sudden cardiac death:
- what are the causes
- stats
- When myocardial ischaemia lasts long enough to cause ventricular fibrillation
- Only 2% of patients survive
meaning of
- transmural
- subendocardium
Transmural: ischaemic necrosis which affects the whole heart
Subendocardium: Ischaemic necrosis which only affects part of the heart muscle wall
What is the reparative process for an M.I.
- cell death
- acute inflammation
- phagocytosis of dead cells
- granulation tissue formed
- collagen deposited
- scar formation
Most common complication within the first 24 hours of an MI?
Arrhythmia
Most sensitive protein marker for an MI
Troponin
Development of the MI
Few seconds: ATP depletion> anaerobic respiration
<2mins : decreased myocardial contractility
A few mins: microvascular changes
20-40 mins: myocardial necrosis
>40 mins: damage to microvasculature
Microbiological appearance
<4 hours: no changes
<12 hours: swollen mitochondria on electron microscope
24-48 hours: pale infarct/ red infarcts/ acute inflammation at edges
>72 hours:
-white/ yellow/red periphery in pale infarct
-little change in red infarct
-chronic inflammation leading to scarring
What is a pale infarct and where does it present
A.C.S. due to arterial occlusion
Presents in solid tissues such as the kidneys, spleen and heart
What is red infarct and where does it present
A.C.S. due to venous occlusion
Presents in loose tissue e.g.lungs, liver
What causes troponin levels to rise?
Myocyte compromise
Most common complication in following week?
myocardial rupture
Which leads show which MIs
2,3 aVF show inferior
v3,v4 show anterior
1,avL, v5,v6 show lateral
