26 CHD Flashcards
what is the difference between a heart attack and cardiac arrest
cardiac arrest is an electrical problem and they will be unconscious
while a heart attack is a circulation problem the person will probably be conscious
what is atherosclerosis
deposition of fatty plaques in coronary arteries
what does atheroma do
narrowing of the arteries lumen
what is angina
angina is a symptom of CHD which is where there is insufficient oxygen supply to myocardium caused by ischaemia
pain characterized by pain in chest arm or neck
what is the difference between stable and unstable angina
stable
predictable pain normally on exertion
almost always caused by atheroma
unstable
pain on less and less exertion or at rest
normally caused by ruptured atheroma
what is varient angina
artery spasm, associated with atheroma
what is microvascular angina
not always due to atheroma, pain often more severe
may not respond to normal treatments for angina
what are myocardial infactions also termed
acute coronary syndrome
what are myocardial infarctions caused by
coronary artery block by rupture of atheroma and thrombus formation
loss of oxygen to the area of heart supplied by the blocked artery leading to a prolonged loss of oxygen, irreversible cell death.
what is embolism
A blood clot that forms in a blood vessel in one area of the body, breaks off, and travels to another area of the body in the blood
how might an embolism form
atheroma
thrombus
ebolism
how do we diagnose a myocardial infarction
the symptoms are similar to angina attack
- palor
- pain
- etc
Traditionally 3 factors used
- patient history of chest pain
- ECG changes
- Cardiac biomarkers
Troponin >99% then classified as Myocardial infarction
How are MI classified
If St segment is elevated then termed STEMI
if St segment normal then classed NSTEMI
what drugs are used in CHD or ACS
Acute - Organic Nitrates
Prophylatic
- Organic nitrates
- Beta blockers
- Calcium Channel Blockers
- Anti-thrombolytic and anti platelet agents
- ACE inhibitors
what does glyceryl trinitrate do
relaxation of smooth muscle by liberation of nitric oxide and subsequent generation of cGMP
Dilate coronary arteries, re-distribute blood to ischaemic region
reduce cardiac oxygen consumption
prevent or relieve coronary spasm
what are the indications of Glyceryl trinitrate
Angina
Heart failure
Extravasation
Anal Fissure
what is the mechanism of action of glyceryl trinitrate
releases nitric oxide in the blood stream, produces cGMP in smooth muscle causing relaxation of all blood vessels including collateral arteries
what are the disadvantages of organic nitrates
prone to development of tolerance
action is short
shelf life short
what are calcium channel blockers
vasodilators also reduce heart rate and force of contraction
what do vasodilators
dilate collateral arteries
reduce oxygen demand on heart, dilate coronary arteries
what are the most common calcium channel blocker
diltiazem and verapamil
in coronary vasospasm what is commonly used
dihydropyridines
what should be avoided in angina
nifedipine
what are some side effects of CCB
include postural hypotension, flushing, constipation,
what is the major side effect of nifedipine
increases mortality following MI
what beta blockers should be used in heart failure and post MI
carvedilol and bisoprolol
what do beta blockers do
reduce oxygen and demand of the heart by inhibiting sympathetic drive to heart
describe the cardioselective properties of beta blockers
little effect on resting heart rate, CO, or arterial pressure
reduce effect of exercise or excitement on the heart due to lower sympathetic drive and effect so lower oxygen demand by heart
what is percutaneous coronary intervention or PCI
catheter inserted in femoral or radial arteries, stents placed in narrow coronary artery
stent is expanded increasing arterial diameter and blood flow
On first presentation of chest pain what should be done
check last episode of chest pain
eliminate non cardiac pain
assess for ACS symptoms
e. g.
- chest pain longer than 15min
- pain associated with nausea, vomiting, sweating, breathlessness or haemodynamic instability
- new onset of deteroiation of stable angina or reoccuring pain not on exertion longer than 15 mins
when should we refer as an emergency
acs suspected
have chest pain or 12 lead ECG abnormal
refer for same day assessment
no reasons for emergency
pain in last 12 hours but now pain free and normal ECG
last pain episode was 12 - 72 hours ago
how do we treat NSTEMI
aspirin 300 mg until clinical decisions made
high risk patients angiogram with follow on PCI angioplasty if required
dual antiplatelet therapy, prasugrel/ticragrelor + aspirin
low risk dual antiplatelet ticagrelor with aspirin
how do we initially treat stemi
aspirin 300 mg until clinical decisions made
most common reperfusion therapy - noramlly PCI
dual antiplatelet therapy for 12 months
