Myocardial Infarction & ACS Flashcards
What is acute coronary syndrome? (ACS)
Umbrella term covering: -ST elevation myocardial infarction (STEMI) -non-ST elevation myocardial infarction (NSTEMI) -Unstable angina
Risk factors for ACS?
*Increasing age *male gender *FHx *Smoking *Diabetes *Hypertension *Hypercholesterolaemia *Obesity
What is the pathophysiology of ACS?
- Initial endothelial dysfunction is triggered by: smoking, hypertension and hyperglycaemia
- Results inchanges to the endothelium including pro-inflammatory, pro-oxidant, proliferative and reduced nitric oxide bioavailability
- fatty infiltration of the subendothelial space by low-density lipoprotein (LDL) particles
- monocytes migrate from the blood and differentiate into macrophages. These macrophages then phagocytose oxidized LDL, slowly turning into large ‘foam cells’. As these macrophages die the result can further propagate the inflammatory process.
- smooth muscle proliferation and migration from the tunica media into the intima results in formation of a fibrous capsule covering the fatty plaque.
- Once plaque formed = blockage or may rupture causing complete occlusion
What is the presentation of ACS?
- Central/left sided chest pain
- Radiates to jaw or left arm
- ‘Heavy” “elephant sat on chest
- Dyspnoea
- Sweating
- Nausea and vomiting
What are the important investigations in ACS?
- ECG
- Cardiac markers e.g. troponin
What is the difference between an NSTEMI and a STEMI?
STEMI =occluding thombus of coronary arteries leading to a full thickness infarct
NSTEMI =subendocardial infarct
What is the difference between unstable angina and NSTEMI/STEMI?
- Unstable angina pain at rest but typically less than 20minutes
- NSTEMI and STEMI pain lasts longer than 20 minutes
What does the mnemonic ROMANCE stand for in the initial management of ACS?
- R eassure
- O xygen (15L)
- M orphine
- A spirin 300mg PO
- N itrate GTN 2 sprays
- C lopidogrel 300mg PO
- E noxaparin 2.5mg SC /Fondaparinux
What is the management of a STEMI?
- A-E assessment + initialy investigations to get diagnosis
- ROMANCE
- Aspirin 300mg PO
- Sublingual GTN
- IV morphine
- Clopidogrel / Ticagrelor
- LMWH Enoxaparin
- Coronary agiography + PCI if
- present within 12hours of onset of symptoms
- can be delivered within 120mins of time when fibrinolysis could have been given
- >12hours but ongoing MI
- PCI treatment (gold standard)
- Give Prasugrel 10mg
- Bivalirudin (direct thrombin inhibitor)
- Fibrinolysis:
- tissue plasminogen activator best or
- Streptokinase/Alteplase/Retaplase/Tenecteplase
- ECG 90 mins following to asses whether greater than 50% resolution
*
What is the secondary prevention of a MI if they have had a previous MI? Consider drugs and lifestyle
Meds
- Dual antiplatelet therapy = aspirin and second antiplatelet i.e. prasugrel or ticagrelor) -can stop 2nd antiplatelet after 12months
- ACEi
- Beta-blocker
- Statin
Lifestyle
- Diet: mediterraneon diet
- Exercise 20-30mins a day
- Sexual activity may resume 4 weeks after uncomplicated MI
What are the complications of a myocardial infarction?
- Cardiac arrest
- Cardiogenic shock
- Chronic heart failure
- Tachyarrhythmia
- Bradyarrhythmias
- Pericarditis
- Left ventricular aneurysms
- Left ventricular free wall rupture
- Ventricular septal defect
- Acute mitral regurgitation
What is the management of an NSTEMI?
- A-E assessment + investigations to give diagnosis
- ROMANCE
- Oxygen
- Morphine
- Aspirin 300mg PO
- Nitrate
- Clopidogrel/Ticagrelow/Prasugrel
- CHASVAS + HAS BLED score
- Use GRACE score to assess future risk
- Fondaparinux antithrombin therapy (if not having angiography in 24hrs)
- IV glycoprotein IIb/IIIa receptor antagonist given to patients with intermediate/higher risk and schedules for angiography
- Coronary agiography within 96hours if predicted 6 month mortality above 3.0%
- Can complete PCI if necessary
ECG changes in which leads corolate to which coronary artert?
Anterior
- Leads V1-V4 = left antertior descending
Inferior
- Lead II, III, aVF = Right coronary
Lateral
- Lead I, V5, V6 = left circumflex
