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
