Ischaemic Heart Disease Flashcards
What two main classifications can ischaemic heart disease be divided into? what do they both consist of?
chronic IHD and acute coronary syndrome
chronic - stable angina, variant angina, silent myocardial ischaemia
ACS - unstable angina, MI
Explain briefly the pathophysiology underlying IHD
Build up of fatty plaques w/in coronary artery walls leading to:
- gradual narrowing - less blood = less O2 reaching myocardium when there is increased demand
- risk of sudden plaque rupture, can cause sudden occlusion of an artery
Explain briefly how fatty plaques are formed
- endothelial dysfunction (big RFs = smoking, HTN, hyperglycaemia)
- Fatty infiltration by LDL particles
- Macrophages phagocytose oxidised LDL, turn into foam cells
- Smooth muscle proliferation and migration from tunica media into intima -> formation of fibrous capsule covering the plaque
What are unmodifiable RFs for IHD?
- age
- m > f
- FHx
What are modifiable RFs for IHD?
- smoking
- DM
- HTN
- Hypercholesterolaemia
- Obesity
What is stable angina
angina induced by effort and relieved by rest
What is unstable angina?
angina of increasing frequency or severity, occurring on minimal exertion or rest
What is decubitus angina?
precipitated by lying flat
What is prinzmetals angina?
angina due to coronary artery vasospasm
How does angina usually present?
- central chest tightness or heaviness
2. may radiate to arm (usually L), neck, jaw or teeth
What are precipitants of angina other than exercise?
emotion
cold weather
heavy meals
What sx is angina associated w?
SOB
nausea
sweating
faintness
What are the Ix for angina?what may they show?
- ECG - usually normal, may show inverted/flat T waves, ST depression or signs of past MI
- Exercise ECG
- Cardiac CT
- Coronary angiogram
What is the pharmacological management of stable angina?
i. Sx relief
ii. Prevention
Sx relief: 1. GTN spray 2. beta-blockers or CCB e.g. diltiazem 3. Long acting nitrate e.g. isosorbide 4. Nicorandil Prevention: 1. Aspirin 75mg OR clopidogrel 2. ACEi (esp in DM) 3. Statins (irrespective of lipid levels)
What is the conservative management of stable angina?
stop smoking
exercise
weight loss
What is the surgical management of stable angina?
Percutaneous transluminal coronary angioplasty
What clinical features point to a diagnosis of unstable angina?
- Increase then decrease in cardiac biomarkers - troponin
- ECG ischaemic changes
- Sx of ischaemia
- Pathological Q waves
What is the presentation of unstable angina?
chest pain
SOB, sweating, N+V
Signs:
pallor, tachycardia, 4th HS, HF (raised JVP, basal creps), pansystolic murmur
What groups of pts are prone to silent MIs?
elderly and diabetic
what post-MI changes are seen on an ECG after:
i. hours
ii. days
i. tall T waves, ST elevation, new LBBB
ii. T wave inversion, pathological Q waves
NB there can also be ST depression or it may be normal
What cardiac enzymes are used to help detect an MI? What changes would you expect to see in their levels post MI including when they peak and return to baseline
- Troponin (T + I):
- increase w/in 3-12hrs from onset of chest pain
- peak at 24-48hrs
- decrease to baseline over 5-14 days - creatine kinase:
- increase w/in 3-12hrs from onset of chest pain
- peak at 24hrs
- return to baseline after 48-72hrs
Give the management of a STEMI
- Aspirin 300mg (consider clopidogrel or ticagrelor)
- Morphine 5-10mg IV
- GTN
- O2
- Resolve perfusion of arteries:
i. Primary PCI - within 12hrs
ii. Thrombolysis - ideally <30m from admission
When is thrombolysis contraindicated in the management of STEMIs
beyond 24hrs
Give the management of an NSTEMI
- ASPIRIN
- nitrates or morphine to relieve pain
- Antithrombin rx - fondaparinux, unfractionated heparin
- Antiplatelet: ticagrelor, prasugrel if PCI (continue either for 12m)
- IV glycoprotein IIb/IIIa receptor antagonists - eptifibatide or tirofiban if increased risk of CV events
- Coronary angiography w/in 96hrs of 1st admission
