myocardial infarction Flashcards
What happens during a myocardial infarction?
- Accumulation of fat (cholesterol) in the intima = atherosclerotic plaque = atherosclerosis
o Intima = layer underneath the top layer of cells in arteries. - The accumulation of fat results in the lumen becoming smaller (creating a higher blood pressure).
- At some point, an ulcer forms on top of the (ruptured) atherosclerotic plaque.
- Our body reacts to this by forming a blood clot on top of it – increasing the risk of the artery getting blocked.
- If the artery gets blocked by a blood clot (thrombosis), oxygen can’t reach certain places in the heart – resulting in a myocardial infarction.
What are the uncontrollable risk factors of a myocardial infarction?
Increasing age – male gender – family history – genetic abnormalities
> this doesn’t mean you are going ot get it for sure, there are tihngs you can do to prevent it
What are the lesser, uncertain and unmodifiable risk factors of a myocardial infarction?
Obesity – physical inactivity – postmenopausal oestrogen deficiency – high carbohydrate intake – hardened unsaturated fat intake – chlamydia pneumoniae infection – high LDL
What are the potentially controllable risk factors op a myocardial infarction?
- hyperlipidaemia
- hypertension
- cigarette smoking
- diabetes
- C reactive protein
Explain hyperlipideamia in regards to myocardial infarction
= excess of fats/lipids in blood
o Cholesterol is important but only in certain amounts.
o We have 2 different types of cholesterol in our body.
1. LDL:Cholesterol produced by the liver that gets sentout to all our organs.
2. HDL:cholesterol that returns to the liver.
o The optimal situation = Low LDL and high HDL
o Factors that determine cholesterol levels:
1. Polyunsaturatedfats+omega-3 fatty acids + sports + limited alcohol consumption -> reduction of LDL cholesterol
2. Unsaturated fats(trans) +obesity +smoking -> LDL accumulation
What are the three types of atherosclerotic plaque build-up
- Aneurysm and rupture: rupture of the coronary artery
- Occlusion(blockage) by thrombus
- Critical stenosis: full blockage of the artery
Zone of necrosis
If blood doesn’t reach the designated areas in the heart, that heart-tissue can die
transmural infarct
along the endocardium (=the inner surface layer)
ischemia
a condition in which blood flow is restricted/reduced in certain parts
IHD
ischemic heart disease
Patients with IDH fall into two large groups:
1=chronic
2=acute
- CAD = coronary artery disease
= Commonly present with stable angina pectoris (chest pain)
» Episodic clinical syndrome
» Usually crescendo-decrescendo in nature
» Typically lasts 2-5 minutes.
» Caused by exertion or emotion. - Acute coronary syndromes
a. NSTEMI = unstable angina pectoris and non-ST-elevation.
» Myocardial ischemia with no evidence of muscle death
» Can occur at rest.
» >10 minutes
» Severe and of new onset (within last 4-6 weeks)
» Occurs with a crescendo pattern (gets worse)
b. STEMI=acutemyocardialinfarctionwithST-elevation.
» Irreversible necrosis
» Commonly known as heart attack.
What are the signs of an infarction?
» Pain, discomfort in chest (Levine’s sign = grab to thorax, very typical)
» Dizzy, vomiting, lightheaded, diaphoresis
» Pain jaw, neck, back
» Pain in arm/shoulder (usually left)
» Shortness of breath (dyspnoea)
» 20-30% no symptoms: sudden and silent death (often diabetic, elderly, hypertension)
How do we clinically assess if someone had a myocardial infarction?
- ECGchanges:STsegmentelevation
2.Blood levels :waste materials of the cardiac tissue increase (we don’t use this to diagnose, rather to rule out the myocardial infarction)
Treatment of a myocardial infarction (medication)
o Statins:i nhibit formation of atherosclerotic plaques -> Inhibits cholesterol metabolism
o Aspirin: less blood clotting (not a drug that’s made for that but the side effect of the drug helps)
What (surgical) procedures can be done after a myocardial infarction?
**1.Angioplasty: **insertion of catheter through the groin towards the blocked artery via a bloodvessel - once in place, the balloon gets inflated -> presses plaque against sides of the artery -> widening the lumen .
2. Coronary artery by pass (CABG): healthy blood vessel get removed from leg/arm/chest -> blocked vessel gets replaced by new one.
3. Transmyocardial laser revascularization
… % of the cases die from a myocardial infarction due to …
33%
cardiac arrythmias
why is a myocardial infarction a chronic disease
because it’s a progressive condition characterised by the build up of plaque in arteries over time
LDL
the primary cholesterol that builds up in the intima
HD
HDL
ensures that excess cholesterol is transported back to the liver
talk about alcohol consumption and a myocardial infarction
drinking a bit of alcohol is good for this situation!!
smoking one pack of cigarettes a day increases the myocardial death rate by … %
200%
talk about hypertension in regards to myocardial infarction
it’s worse for a brain infarction than a myocardial infarction
o 60% higher risk of atherosclerosis and eventually also myocardial infarction.
o Must be treated; if not, large portion will eventually die (to blockage of blood vessels, or heart failure)
o Gradually increases; slumbering, silent killer (from the age of 20!); you only notice it during critical stages
“Episodic clinical syndrome” explain in regards to CAD
the artery isnt completely closed but occasionally the blood doesn’t flow through properly, causing occasional short pains
what does unstable angina tell us
it usually indicates that a myocardial infarctoin is nearby and is treated very seriously
what does nonST elevation tell us
that a myocardial infarction hasn’t happened YET
diaphoresis
excessive sweating
palpitations
rapid pounding heartbeats
dyspnoea
shortness of breath
explain troponin levels in regards to myocardial infarction
if you have an infarction, troponine increases, the higher troponine, the worse the infarction
