ACS / MI Flashcards
What 3 things does ACS include?
- STEMI
- NSTEMI
- unstable angina
How is unstable angina different to stable angina?
- increasing severity
- recent onset
- unpredictable
- occurs at rest (unlike stable angina)
- may be previous deterioriation of stable angina
What are clinical features of unstable angina?
- chest pain daily/several times per day
- increasing severity of chest pain
- retrosternal chest pain radiating to jaw, arm, neck
- sweating
- nausea
- tachycardia
- dyspnoea
- 4th heart sound
- carotid bruit
What are the symptoms of an acute STEMI?
- acute central chest pain (can last for hours)
- pain radiating to arms, neck, jaw, back + epigastrium
- dyspnoea
- nausea/vomiting
- sweating
- restlessness
- palpitations
- 20% of pts have no pain (silent) eg. elderly, diabetics or post-transplant pts - this goes unnoticed or may be present with hypotension, syncope, arrhythmias, pulm oedema, epigastric pain, acute confusion, stroke
What are signs of an acute STEMI?
may present with no physical signs unless complications develop athough patient often appears:
- anxious
- pale
- grey
- inc BP
- signs of HF
What investigations are done for STEMI?
- bloods - FBC, U+Es, glucose, lipids
- ECG
- cardiac markers - troponin, CK, AST + LDH
- CXR -> cardiomegaly, pulm oedema, wide mediastinum
- coronary angiogram -> thrombus present w/ occlusion
What might happen in an ECG days later following an MI?
- ST segment usually returns to normal
- T wave may return to upright
- however, Q wave remains - sign of prev MI
What ECG leads give rise to what kind of MIs? Also give the blood vessels involved
Necrotic cardiac muscle releases several enzymes and proteins into the systemic circulation.
When are these measured and what do these include?
- done at 0h, 6h and 12h after admission
- troponin T + I - regulatory proteins, highly specific + sensitive for cardiac muscle damage (myocardial necrosis), serum levels inc within 3-12h from onset of chest pain, peak at 24-48h and return to baseline over 5-14days
- CK - also produced by sk muscle + brain, is less sensitive than troponin. CK-MB however is specific for heart muscle damage, it’s a myocardial-bound isoenzyme fraction of CK + the size of enzyme rise is broadly proportional to infarct size. Serum levels inc within 3-12hrs from onset of chest pain, reaches peak values within 24hr and returns to baseline over 2-3 days
For a further episode of chest pain >3 days after first episode, CK-MB is the most useful marker. Troponin levels will remain elevated since first episode and won’t provide info regarding a new episode.
What is the diagnostic criteria for an acute MI?
Rise + fall of serum cardiac biomarkers such as troponin and CK-MB, accompanied w/ at least one of the following:
- symptoms of ischaemia
- ECG changes of new ischaemia (ST/T changes or new LBBB)
- development of pathological Q waves
- coronary artery intervention
- imaging evidence of new loss of viable myocardium
What is the immediate management of a pt having an acute myocardial infarction?
- ABCDE!
- oxygen 2-4L, aim for SaO2 >94% (unless COPD pt)
- brief history + exam, 12-lead ECG, BP, bloods (cardiac enzymes, FBC etc)
- aspirin 300mg PO unless already given and clopidogrel 300mg PO
- morphine 5-10mg IV + antiemetic eg. metaclopramide 10mg IV
- GTN sublingually 2puffs or 1 tablet PRN
- reperfusion: primary PCI or thrombolysis w/ dalteparin for 24-48hr (LMWH/UFH)
- beta blocker eg. atenolol 5mg IV (unless asthma or LVF)
- high intensity statin
MENUMONIC: MONARCH (morph, o2, nitrates, aspirin, reperfusion, clopidogrel, heparin)
The time frame for door-to-needle thrombolytic administration should be within 30 mins, whereas the door-to-balloon PCI time should be less than 90 minutes.
What are contraindication for thrombolysis?
- ABSOLUTE:
- any active bleeding from any site within body
- any recent history of haemorrhagic stroke
- pregnancy
- taking warfarin
- RELATIVE:
- active liver disease
- peptic ulcer disease
What is the long-term management for STEMI?
- education + lifestyle advice
- beta-blocker, atenolol 5mg unless CI
- atorvastatin
- ACEi
- dual antiplatelet therapy for 1 yr - clopidogrel 300mg
- aspirin
What is the specific management for NSTEMI?
- beta-blocker, atenolol 5mg unless contraindications
- LMWH
- IV nitrates
- consider for coronary angiography and PCI
- grace score
- assess for low risk or high risk and treat appropriately:
LOW-RISK (no further pain, flat or inverted T or normal ECG + negative troponin) -> maybe discharge if repeat troponin is negative after 12hr
HIGH-RISK (persistent or recurrent ischaemia, ST dep, diabetes, inc troponin) -> infusion of glycoprotein 2b/3a antagonist + clopidogrel
What factors to assess and intervene on are important to touch up on post-MI, in a primary care setting?
-
Assessment of:
- attitude + psychological state
- exercise + abilities and propensities
- dietary habits + knowledge
- smoking habits
- blood pressure
- full lipid profile (cholesterol will be lower than usual for 6weeks post MI)
-
Intervention:
- cardiac rehab
- stop smoking (record smoking status + advice)
- dietary advice w/ weight control if indicated
- control BP - tx threshold is 140/90
