Acute Coronary Syndrome Flashcards by Philip Meakin

What three conditions make up ACS?

STEMI
NSTEMI
Unstable Angina

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What is the difference between ischaemia and infarction?

Infarction is when there is death of tissue due to low oxygen supply
Ischaemia is when there is a low oxygen supply but not tissue death

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What causes the pain in ischaemia?

Production of lactic acid leads to the pain experienced

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What is the underlying pathology in a myocardial infarction?

Rupture of an atherosclerotic plaque causes thrombus formation, this then obstructs the flow of blood leading to ischaemia distally

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Briefly describe the blood supply to the heart

RCA and LCA are the first branches of the Aorta and arise from the aortic sinus
LCA divides into Circumflex and LAD
RCA sometimes gives off Posterior Descending Artery (80%) or this may come from the Circumflex (15%) or from both (5%). Termed left/right or co dominant.

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What does the RCA supply?

Right atrium and ventricle

If Posterior descending- Inferior and posterior walls

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What are the inferior leads?

II, III, aVF (think F in inferior)

RCA/Posterior descending

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What does the LAD supply?

Anterior aspect of LV
Anterior aspect of septum
Apex

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What does the circumflex supply?

Lateral wall of LV

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What are the lateral leads?

V5 and V6 and aVL and I-

Circumflex Artery

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What are the anterior leads?

V3 and V4

LAD

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What are the septal leads?

V1 and V2-

LAD and RCA

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What is the blood supply to the SA node?

RCA gives sinoatrial node off in 60%

Can arise from left circumflex

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What is the blood supply to the septum?

LAD- Anterior septum

RCA- Posterior Septum

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Which group of patients might have an atypical presentation for an MI?

Diabetic and elderly

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How might patients with an atypical presentation present?

Dyspnoea- due to pulmonary oedema
Epigastric pain
N and V
Pallor
Sweating
Syncope- poor cerebral perfusion

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How do the three ACS presentations differ from each other?

Unstable Angina- No troponin rise, ECG normal or ischaemic changes
NSTEMI- Troponin rise, ECG normal or ischaemic change
STEMI- Troponin rise and ST elevation on ECG

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What is a troponin rise indicative of?

Myocardial infarction and the death of myocytes

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Which troponins are measured?

Troponin T and I

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What are some other causes of a raised troponin?

Renal failure
Sepsis
Anaemia
PE
Aortic dissection

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Why can a single troponins not be used in isolation?

It is the troponin rise that is important, baseline is taken and then another 6-12 hours apart

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For patients presenting with an ACS picture, what immediate investigations would you request and why?

Bloods-
Troponins
FBC Anaemia, Infection
U and Es Renal Function, Important for anti-hypertensive meds too
LFTs- before starting statins
Lipids- risk factor profile
HBA1c/Fasting Glucose- risk factor profile
TFTs- Tachycardia from hyperthyroidism can trigger chest pain

ECG- Ischaemic Changes
Minutes- Hyper acute T Waves
Hours to Days to Weeks- ST Depression/ST Elevation/T Wave Inversion
Days- Pathological Q Waves

ECHO-
Assess myocardial function and for valve disease if suspected

CXR-
Rule out other causes of acute chest pain

CT Angiogram- Gold standard for investigating vessel disease in the heart

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What are some signs of ischaemia on ECG?

ST Elevation
ST Depression
T wave inversion
Pathological Q Waves

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What would you check for on examination of an ACS patient?

This is a medical emergency so requires an A to E approach

A- Airway
B- Auscultate- bi-basal crackles, percussion and palpation for chest expansion
C- Blood pressure, HR, Heart Sounds, CRT, JVP, Temperature, Pulse, Urine output

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How many leads must ST elevation be present in for it to be classed as a STEMI?

At least two or more sister leads

What are some features that suggest pain is more cardiac in origin?

Central- behind the sternum Poorly localised (if they can point to a specific point it is more likely to be MSK) Radiation down the L arm and into the jaw/neck Crushing/Dull in nature Associated dyspnoea, N+V, pallor, sweating Risk factors present- FHx, Diabetes, Smoking, HTN, Hyperlipidaemia, Male gender

What type of cardiac pathology pain eases with leaning forward?

Pericarditis

What type of cardiac pathology pain feels like a tearing sensation with radiation to the back?

Aortic dissection

What ECG findings might be seen for a NSTEMI?

ST Depression T Wave Inversion Or may be normal

Can both STEMIs and NSTEMIs be localised to an anatomical area?

No only acute STEMIs can be localised | NSTEMIs cannot as the ischaemia changes do not correspond to the ischaemic vascular territory

What areas are infarcted in NSTEMIs and STEMIs?

STEMIs- Transumaral infarcts | NSTEMIs- Subendocardial infarcts- this is the first area to undergo ischaemia when the blood supply is reduced

What features on an ECG indicate STEMI?

ST Elevation | Or NEW ONSET LBBB

What is the initial approach for suspected ACS?

Medical Emergency so A to E approach ECG confirms if STEMI or NSTEMI/Unstable Angina

What is the initial treatment if STEMI?

Follow ACS Protocol for Trust Aspirin 300mg Another Anti-platelet- Clopidogrel/ Ticagrelor Morphine 5-10mg IV repeat and titrate after 5 minutes Anti-emetic- metoclopramide 10mg IV (cyclizine increases HR) GTN Oxygen- only if their oxygen saturations are below 95% LMWH- Enoxaparin treatment dose Beta blockers- Bisoprolol ACEi- Started within 24 hours Cardiac Reperfusion- PCI or if not available within 120min thrombolysis

Within what time frame of symptom onset must patients with STEMI have presented to be considered for PCI?

12 hours

What is a contra indication to giving nitrates?

Hypotensive

What are some side effects of nitrates?

Flushing Headache N and V Hypotension

What is the mechanism of action of aspirin?

COX inhibitor that prevents platelet aggregation

What dose of aspirin is given if ACS is suspected?

300mg Stat

What does of aspirin is given for long term secondary prevention?

75mg OD

What is a side effect of aspiring, how could this be reduced?

Increased risk of gastric ulcers and upper GI bleeds- therefore a PPI may be given too Also it is nephrotoxic so close monitoring of renal function is required

What second anti-platelet (in-addition to aspirin) is now commonly used?

Ticagrelor Clopidogrel may also be used if there is a higher risk of GI bleeding as it has a reduced risk

What is the mechanism of action of Ticagrelor?

P2Y12 receptor antagonist

What are the doses of ticagrelor, loading and daily?

180mg loading dose | 90mg BD

What is the management for NSTEMI?

As with STEMI and other ACS BATMAN ``` Beta blockers- unless CI- asthma, bradycardia, never with verapamil or diltiazem Aspirin 300mg Ticagrelor 180mg Morphine + Metoclopramide Anticoagulants- Enoxapain treatment dose Nitrates- relieve coronary artery spasm ``` Then Risk assess for consideration of PCI to treat the underlying coronary artery disease

What score is used to risk assess NSTEMIs? What is it a risk of?

GRACE Score- 6 month risk of repeat MI or death

What agents are used for thrombolysis?

TPAs- Tissue Plasminogen Activator Streptokinase Alteplase Tenectaplase

What are some complications from MI?

DREAD ``` Death Rupture- Myocardium/Papillary Muscles Edema- Heart Failure Arrthymia and Aneurysm Dresslers Syndrome ```

What is Dresslers syndrome?

Pericarditis that occurs after MI due to the ongoing inflammation. Presents with chest pain and a low grade fever. A pericardial rub may be head on auscultation.

What is the treatment for a pericardial effusion caused by Dressler syndrome?

Pericardiocentesis An ECHO confirms the presence of an effusion

What features are seen on the ECG for Dressler syndrome?

Global ST elevation and T wave inversion

What is the management of Dressers syndrome?

NSAIDs Severe cases Prednisolone Pericardiocentesis if there is an effusion

What medicines are used in the secondary prevention of MIs?

6 As Aspirin 75mg OD Another Anti platelet- Ticagrelor or Clopidogrel for up to 12 months Atorvastatin- 80g OD ACEi- e.g. Ramipril Atenolol (Beta Blocker, more commonly bisoprolol) ARB- Eplerenone

Why are ACEi or ARBs particularly useful to start post MI?

They reduce ventricular re-modelling after an MI

What are some side effects of ACEi?

Hypotension | Cough

Why are beta blockers (e.g. bisoprolol, atenolol) given after MI?

Increase cardiac perfusion during diastole by reducing the HR Not to be given if bradycardia, heart block, asthma, COPD

What ARB is useful to give post MI?

Eplerenone - proven mortality benefit in heart failure and prevents ventricular remodelling like ACEi. Initiated if LVEf less than 40%

What must be checked before starting someone on a a statin>

LFTs

What blood test can check for an important complication of statins?

CK Rhabdomyolysis is the complication, monitor renal function too as myoglobin is nephrotoxic.

What is a leading side effect of statins?

Muscle aches- consider reducing the dose from 80mg to 40mg.

When is eplerenone started in patients after MI?

If there is evidence of heart failure- LVEF <40%

Acute Coronary Syndrome Flashcards

(61 cards)