ACS + MI Flashcards
What is Acute coronary syndrome (ACS)?
encompasses unstable angina, non-ST elevation myocardial infarction (NSTEMI) and ST-elevation myocardial infarction (STEMI).
typically manifests as sudden, new-onset angina, or an increase in the severity of an existing stable angina.
What is Acute coronary syndrome (ACS)?
encompasses unstable angina, non-ST elevation myocardial infarction (NSTEMI) and ST-elevation myocardial infarction (STEMI).
typically manifests as sudden, new-onset angina, or an increase in the severity of an existing stable angina.
Epidemiology of ACS
- STEMI = 5/1000 per annum in UK
- M>F
RFs for ACS
- Age (>65 years of age)
- Male
-
Family history of premature coronary heart disease
Smoking
Diabetes
HT
Obesity
Drugs
Atherosclerotic plaque formation
- Thefirst stageof atherosclerotic plaque formation involves the accumulation of low-density lipoprotein cholesterol in the inner layer of the blood vessel
- Leukocytes adhere to the endotheliumand gain entry into theintima, where they combine with the lipids to becomefoam cells
- Artery remodellingandcalcification, alongside the presence offoam cells, causes atherosclerotic plaques to form
- Rupture of a plaquecauses platelet activation, thrombus formation and coronary artery occlusion. (The thrombus is mainly made up of platelets)
- This results in ischaemia and infarction
What happens in unstable angina and NSTEMI
Occlusion is partial
What happens in STEMI
Occlusion is complete
STEMI, ischaemia is initially just subendocardial, but eventually becomes transmural.
Signs of ACS
- Hypotension or hypertension
- Reduced 4th heart sound
- Signs of heart failure: e.g. increased JVP, oedema; **red flag symptom
- Systolic murmur: if mitral regurgitation or a ventricular septal defect develops
Symptoms of ACS
- Shortness of breath
- Sweating and clamminess
- Nausea and vomiting
- Palpitations
-
Anxiety: often described as a ‘sense of impending doom’
Chest pain
Primary investigations for ACS
First line: ECG - perform every 10 minutes
Troponin:for a STEMI and NSTEMI, troponin levels will begin to elevate 4-6 hours after injury and will remain elevated for roughly 10 days. In unstable angina, there isnoelevation in troponin.
ECGs for ACS
Thyroid function tests
HbA1C and fasting glucose
FBC
U&Es
LFTs
CXR
Immediate management for unstable angina + NSTEMI
Oxygen
Analgesia: Morphine & Sublingual glyceryl nitrate
Dual antiplatelets: Aspirin + Prasugrel, ticagrelor or clopidogrel
Anticoagulation: Fondaparinux + unfractionated heparin
BBs
MONA: Morphine oxygen nitrates aspirin
STEMI immediate management
Oxygen
Analgesia: Morphine & Sublingual glyceryl nitrate
Dual antiplatelets: Aspirin + Prasugrel, ticagrelor or clopidogrel
What is a PCI
first-line method of revascularisation; insertion of a catheter via the radial or femoral artery to open up the blocked vessels using an inflated balloon (angioplasty), and a stent may also be inserted
Symptom onset within 12 hours AND access to PCI within 2 hours for STEMI management
PCI
- Anticoagulation and further antiplatelet therapy
- Unfractionated heparinand aglycoprotein IIb/IIIa inhibitor
- Bivalirudinmay be used as an alternative to unfractionated heparin
Management for STEMI if ineligible for PCI
-
Thrombolysis e.g. alteplase or tenecteplase
- IV administration of a fibrinolytic agent
- Offered if symptom onset is greater than 12h OR PCI not available within 120 mins
-
Anticoagulation
- An antithrombin agent such as unfractionated heparin is usually given alongside thrombolysis
- ECG:if the ECG shows residual ST elevation after 60-90 minutes of thrombolysis, offer immediate angiography and PCI
Early complications for ACS
Post - MI pericarditis
Cardiac arrest/ tachyarrhythmias
Cardiogenic Shock
MR
Ventricular septal defect
Late complications of ACS
- Dressler’s syndrome:presents similarly to post-MI pericarditis but occurs2-6 weekspost-MI, and reflects anautoimmuneprocess against neo-antigens formed by the heartDiagnosis:ECG(global ST elevationandT wave inversion),echocardiogram (pericardial effusion) and raisedinflammatory markers(CRPandESR).Management:NSAIDs(aspirin/ibuprofen) and in more severe cases steroids (prednisolone). May needpericardiocentesisto remove fluid around the heart.
- Heart failure:ventricular dysfunction following extensive damage can lead to chronic heart failure
- Left ventricular aneurysm: bulge or ballooning of a weakened area of the heart
Prognosis of ACS
Unstable anginahas a better outcome than anNSTEMIorSTEMI.
NSTEMIs and STEMIs have similar long-term outcomes. 5-10% of patients with ACS are predisposed tore-infarction.
Poor prognostic factorsinclude: increasing age, the magnitude of troponin rise, arrhythmias, left ventricular dysfunction,renal impairment, diabetes, anaemia, cerebrovascular disease
What is a myocardial infarction?
Death of heart muscle cells via necrosis due to lack of blood flow
Pathophysiology of MI
MI happens when coronary circulation becomes blocked
Mostly due to endothelial cell dysfunction relating to inflammation of tunica intima - toxins from tobacco can cause this
Damage becomes site for atherosclerosis
How does an atherosclerotic plaque form
Starts with fibrous cap
In core of atherosclerotic plaque T lymphocytes, smooth muscle cells, macrophages, lipids
NSTEMI MI pathophysiology
LAD blocked > Inner 3rd of myocardium first area affected
Blockage suddenly breaks down + blood flow returns damage is limited to the inner 3rd
Called subendocardial infarct - ECG shows no ST elevation
NSTEMI MI features
Causes of subendothelial infarct and hypotension
Pathophysiology of STEMI MI
3-6 hours zone of necrosis extends through entire wall of thickness - transmural infarct
Shows ST segment elevation
Complications of of STEMI MI
HF
Arrhythmias
Pericarditis
Cardiogenic shock
Granulation tissue
Treatment for MI
Fibrinolytic therapy - medication to breakdown Fibrin in blood clots
Angioplasty - Deflated balloon inserted into blockage then inflated to open the artery
PCI - catheter used to place stent in coronary artery to open up blood vessels
What is reperfusion injury
Tissue damaged by returning blood
Medications for MI
Antiplatelets - Aspirin
Anticoagulatn - Heparin or LMWH
Nitrates - relax coronary arteries - lower preload
BB
Pain medication
Statins
Symptoms of MI
Chest pain/ pressure
Diaphoresis
Dyspnoea
Nausea
Fatigue
Left arm/ jaw pain
3 most commonly blocked arteries in MI
LAD: Anterior wall + interventricualr septum 40/50% of cases
RCA : Posterior wall, septum + Papilary muscles of LV - 30/40% of cases
LCA: Lateral wall of LV - 15/20% of cases