Acute Coronary Syndromes- Myocardial Infarction

Question 1

What is myocardial infarction?

Answer 1

Heart muscle tissue/cell necrosis due to it lack of blood therefore oxygen supply

-acute coronary syndrome and ischaemic heart disease

Question 2

What is mi caused by?

Answer 2

Blokage of coronary arteries by a thrombosis/ ruptured plaque/ cholesterol therefore blood isn’t delivered to heart tissue

Question 3

What are the symptoms of MI?

Answer 3

Can vary.

• central chest pain spreading to left shoulder, jaw and neck
• nausea
• pallor
• nausea
• sweating
• syncope
• dyspnoea

-TREAT ASAP

Question 4

What can MI be classified as?

Answer 4

• STEMI (ST elevation or new onset left bundle branch block)

- NSTEMI, NSTEMI can still cause serious necrosis

Question 5

How to diagnose an MI?

Answer 5

• cardiac biomarkers (troponin rises, creatine kinase but is less specific)
• symptoms
• posterior MI with V7-V9 leads)
• ECG. STEMI showing ST elevation or new LBBB and NSTEMI - ST depression, flat/inverted T waves

pathological Q waves hours later,

Question 6

How to differentiate MI from unstable angina?

Answer 6

MI releases troponin whereas unstable angina doesn’t

Question 7

What are less common features of stroke?

Answer 7

• W/o chest pain= syncope, vomiting, stroke, confusion

Question 8

What are signs of MI?

Answer 8

Pallor, increased or decrease pulse, increase or decreased BP, anxiety, S4.

• Pansystolic murmur shows signs of papillary muscle disruption

Question 9

What would heart failure show?

Answer 9

• Increased jvp, S3, Basal crepitations

Question 10

What are other investigations you would carry out?

Answer 10

• ECG
• U&E
• Glucose test
• FBC
• CXR
• Cholesterol

Question 11

What is the treatment for STEMI?

Answer 11

• Dual anti platelet therapy (Aspirin 300mg, then one of Ticagrelor (180, #1), Prasugrel (60), Clopidogrel (300, less preferred).)
• Oxygen (if SaO2 <95, breathless, acute LVF)
• Morphine (5-10mg) + Anti emetic Metoclopramide
• Beta blockers (not in those with asthma/COPD, heart block, heart failure, cardiogenic shock)
• PCI (Angioplasty- catheter via femoral or radial artery, balloon, then stent.) Identify blockage via angiography
• Anticoagulants (injectable, BIVALIRUDIN (#1), if not Enoxaparin +- GP 11b/111a blocker)

Question 12

What if PCI for STEMI is not available? (e.g. the patient cannot get PCI within 2 hours)

Answer 12

• Fibrinolysis/thrombolysis
• dissolves the clot
• plasminogen attaché to plasmin enzyme which is activated and breaks down the clot.
• TISSUE PLASMINOGEN ACTIVATORS e.g. tenecteplase as single IV bolus)

-then transfer to Primary PCI centre for rescue PCI if fibrnoylsis has been unsuccessful or for angiography

Question 13

What is the treatment for NSTEMI?

Answer 13

• Stabilise with medical therapy and risk assess those in need of further help, get an angiography.
• LLOW FLOW O2 (Sao2<90%, breathless)
• MORPHINE (5-10 mg IV + metoclopramide 10mg IV)
• NITRATES( GTN sray or sublingual tablets as required)
• ASPIRIN (300mg PO, 75mg for afterwards ones)
• THEN. Measure troponin and clinical parameters to risk assess via the GRACE score

1. INVASIVE STRATEGY, intermediate -> high risk GRACE score. (rise in troponin, or dynamic ST or T changes, diabetes, CKD, LVEF <40%, early angina post MI, recent PCI, prior CABG)
   a) - Fondaparinux (Factor Xa inhibitor 2.5 mg OD SC or LMWH Enoxaparin 1mg/hr) Continue until discharge.

b) -Second anti platelet agent (ticagrelor 180, prasugrel 60 if going for PCI, CLOPIDOGREL 300 for lower risk)
c) Nitrate (IV)
d) Oral Beta blocker (Bisoprolol 2.5)

e- final step.

• Cardiologist review for angiography.
• 1. Urgent (<120 min, ongoing angina and ST changes, signs of Cardiogenic shock or life threatening arrhythmias
• 2. Early (<24hrs). GRACE >140, high risk
• 3. Within 72 hrs if low risk

2. CONSERVATIVE STRATEGY
   - NO recurring chest pain, heart failure, normal ECG)
   - Discharge but check troponin interval and arrange investigations outpatiently e.g. Stress test)

Question 14

What is the management of STEMI after initial treatment?

Answer 14

1. protect the heart - dual antiplatelet therapy(Aspirin 75mg + Ticagrelor or Prasugrel or Clopidogrel), and anticoagulants for a year post MI
2. change the lifestyle- smoking cessation, healthy diet, Gp support for mental health, daily exercise, treating Diabetes, Hypertension, hyperlipidaemia
3. control the symptoms- GTN and opiates

Question 15

How to treat STEMI patients who have not received reperfusion (presenting symptoms >12hrs)

Answer 15

• Fondaparinux or Enoxaparin/unfractionated heparin if fondaparinux isn’t available.

Question 16

What are contraindications to tenecteplase?

Answer 16

• previous intracranial haemorrhage
• ischaemic stroke <6months
• cerebral malignnancy
• recent major trauma/surgery <3weeks
• GI bleeding
• known bleeding disorder
• aortic dissection
• anticoagulant therapy
• pregnancy <1week
• advanced liver disease
• infective endocarditis

Question 17

What are contraindications for oral beta blockers? Therefore what are alternatives?

Answer 17

• heart failure, heart block, cardiogenic shock, asthma.COPD,
• Rate limiting calcium antagonist Verapamil (80-120mg/8hr)
• Diltiazem (60-120mg/8hr)

Question 18

Following acute management of NSTEMI, what is the management thereafter?

Answer 18

• Dual antiplatelet therapy, ace inhibitors, statin and beta blocker.

Question 19

Ticagrelor is the preferred second AP agent for higher risk groups. What are the higher risk groups?

Answer 19

Previous MI, CABG, TIA, stroke, >60 yrs, coronary artery stenosis >_50% in >_2 vessels, peripheral arterial disease, chronic kidney disease

Question 20

What should you do alongside giving ACEi?

Answer 20

monitor renal function