Chapter 4: Cardiac Causes of Cardiac Arrest Flashcards

1
Q

How can acute coronary syndrome be split up?

A

ST elevated myocardial infarction

Non ST Elevated acute coronary syndromes:

  • NSTEMI
  • Unstable angina
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2
Q

What can be used to determine between STEMI and NSTEMI?

A

ST elevation or new LBBB = STEMI

Other ECG changes = NSTEMI/Unstable angina

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3
Q

How do you differentiate between unstable angina and NSTEMI?

A

Troponin release

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4
Q

What may indicate that a non-ST elevated ACS may be high risk?

A
ST depression
Dynamic ECG changes (different from baseline)
Unstable rhythm
Unstable haemodynamics
Diabetes
High GRACE score
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5
Q

Which groups of people may present with ACS less typically?

A

Females
Elderly
Diabetics

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6
Q

What are some atypical symptoms of ACS?

A

Indigestion type pain
Pain radiate to throat, into one or both arms, into back or upper abdomen
Asymptomatic

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7
Q

What ECG changes can an NSTEMI/unstable angina show?

A

Normal
ST Depression
Non specific abnormalities - t wave inversion

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8
Q

When is risk of progression from NSTEMI to full occlusion highest?

A

First few hours, days and months

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9
Q

What is there a substantial risk of in the acute phase of a STEMI?

A

VF
VT
Sudden death

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10
Q

What ECG changes may be seen in a STEMI?

A
ST elevation
New LBBB
Pathological q waves
T wave inversion
Hyperacute t waves (v early)
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11
Q

How quickly do you aim to give PCI in a STEMI? What should you do if this can not be achieved?

A

Within 120 minutes of onset of chest pain

Fibrinolytic therapy

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12
Q

Which leads indicate where an infarct may be?

A

Anterior - V1-4 = LAD
Inferior - II, III, AVF = RCA
Lateral - I, AVL, V5-6 = Left Circumflex
Posterior - Reciprocal changes to anterior (ST Depression in V1-4) = RCA

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13
Q

What is important to know about posterior MI’s?

A

Must confirm with posterior leads

Risk of bradycardia as SAN may be affected

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14
Q

What other conditions can cause acute ST depression or t wave inversion?

A

Subarachnoid haemorrhage
Traumatic brain injury

Major PE - t wave inversion

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15
Q

Why is echocardiography useful in acute ACS?

A

Confirm LV systolic function - related to prognosis

Can prompt diagnoses of cardiomyopathy, valve disease, pericardial disease, aortic dissection and PE

Can confirm RV dilatation and impairment

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16
Q

What are the GRACE and CRUSADE scores?

A

GRACE - predict risk of adverse outcome

CRUSADE - Risk of major bleeding during hospital admission following ACS

17
Q

Within what time frame should reperfusion be post STEMI without delay?

A

If presenting within 12 hours - PCI or fibrinolysis

18
Q

What anti-thrombotic therapy should patients having a PCI be given and what dose?

A

Aspirin 300mg + 1 of

  • Clopidogrel 600mg
  • Prasugrel 60mg (not if >75, <60kg or hx of bleeding/stroke)
  • Ticagrelor - 180mg

Anticoag with heparin is given in Cath lab - Bivalirudin is alternative

In high-risk, glycoprotein IIb/IIIa inhibitor may be given

19
Q

What are the typical indications for fibrinolytic therapy?

A

1 of:
- STEMI >0.2mV in 2 adjacent chest leads or >0.1mV in 2 adjacent limb leads

  • Dominant R waves and ST depression in V1-3 (post MI)
  • New onset LBBB
20
Q

What is given alongside fibrinolytic therapy for STEMI?

A
  • Aspirin 300mg loading dose AND
  • Clopidogrel 300mg loading dose AND
  • Antithrombin therapy: LMWH, unfractionated heparin or fondaparinux
21
Q

Describe the repercussion flow diagram for a patient with a STEMI

A

Hospital provide PPCI - immediate PPCI

No PPCI available within acceptable time frame –> fibrinolysis

Fibrinolysis fail –> transfer to PCI hospital
Fibrinolysis successful –> angiography ± PCI during same admission

22
Q

What are the absolute contraindications for fibrinolytic therapy?

A
  • Previous haemorrhage stroke
  • Ischaemic stroke during last 6 months
  • CNS damage/neoplasm
  • Recent major surgery, trauma or head injury (<3wk)
  • Active internal bleeding (not menses) OR GI bleed within past month
  • Known/suspected aortic dissection
  • Known bleeding disorder
23
Q

What are the relative contraindications for fibrinolytic therapy?

A
  • Refractory HTN >180 mmHg
  • TIA <6months
  • Oral anticoagulant treatment
  • Pregnancy or <1wk post partum
  • Traumatic CPR
  • Non-compressible vascular puncture
  • Active peptic ulcer disease
  • Advanced liver disease
  • Infective endocarditis
  • Previous allergic reaction to fibrinolytic drug
24
Q

What may suggest that fibrinolytic therapy has failed?

A

Record ECG 60-90mins post.

Failure for ST elevation to resolve by >50% compared to pre-treatment

25
Q

How are patients with a non ST elevated ACS treated to prevent thrombus formation?

A
  • SC LMWH therapeutic dose 12hr or Fondaparinux OD
  • Aspirin 300mg loading then 75mg daily

If NSTEMI or planned for angiography ± revascularisation

  • Clopidogrel 300mg (or 600mg loading) then 75mg daily
  • Prasugrel 60mg then 10mg daily
  • Ticagrelor 180mg then 90mg BD

Can consider glycoprotein IIb/IIIa inhibitor

26
Q

How are patients with a non ST elevated ACS treated to reduce myocardial O2 demand?

A
  • Beta blockers - diltiazem if BB CI
  • Avoid DHAP Ca2+ blockers
  • IV nitrate infusion if angina persist
  • Consider ACE inhibitor - LV impairment or heart failure
  • Treat complications
27
Q

How quickly should a patient with an NSTEMI have coronary angiography?

A

Within 72h of presentation

28
Q

Which ventricular arrhythmia’s can complicate ACS?

A

Cardiac arrest with VF or pulseless VT - presentation

If VF/pVT occur within 48h of STEMI and recovery uncomplicated - risk of recurrence low

VF/pVT in context of Non ST elevated ACS - risk of further ventricular arrhythmia

If ventricular arrhythmia late complication - see by rhythm specialist for ICD implantation

29
Q

Which other arrhythmia’s may occur in context of ACS?

A

AF - indicate left ventricular failure

AV block - inferior AMI

30
Q

How should AV block in context of ACS be managed?

A

Treat bradycardia with atropine

Consider temporary pacing if this fails

PCI typically resolve heart block

31
Q

What are the complications of ACS?

A

Arrhythmia
Heart Failure
Cardiogenic Shock

32
Q

How can cardiogenic shock due to ACS be managed?

A

Inotropic therapy - adrenaline
Intra-aortic balloon pumping
Mechanical circulatory/ventilatory support

33
Q

What are some other causes of sudden cardiac death and how do they cause cardiac arrest?

A

Long QT - Torsades, VT, VF
Brugada
Short QT - Torsades, VT, VF
Catecholaminergic polymorphic VT - Torsades
Arrhythmogenic RV cardiomyopathy - VT, VF
HOCM - VT, VF
WPW - AF transmit to ventricles - VT, VF
High grade AV block - asystole (can Torsades/VT/VF)
Aortic stenosis - HF, VT, VF
Dilated cardiomyopathy - VT, VF