Chapter 4: Cardiac Causes of Cardiac Arrest Flashcards by Ronan Docherty

How can acute coronary syndrome be split up?

ST elevated myocardial infarction

Non ST Elevated acute coronary syndromes:

NSTEMI
Unstable angina

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What can be used to determine between STEMI and NSTEMI?

ST elevation or new LBBB = STEMI

Other ECG changes = NSTEMI/Unstable angina

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How do you differentiate between unstable angina and NSTEMI?

Troponin release

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

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

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Which groups of people may present with ACS less typically?

Females
Elderly
Diabetics

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What are some atypical symptoms of ACS?

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

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What ECG changes can an NSTEMI/unstable angina show?

Normal
ST Depression
Non specific abnormalities - t wave inversion

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

First few hours, days and months

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

VF
VT
Sudden death

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What ECG changes may be seen in a STEMI?

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

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

Within 120 minutes of onset of chest pain

Fibrinolytic therapy

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Which leads indicate where an infarct may be?

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 and dominant R wave in V1 AND V2)= RCA

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What is important to know about posterior MI’s?

Must confirm with posterior leads

Risk of bradycardia as sinoatrial node may be affected

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What other conditions can cause ST elevation or depression, not related to the heart?

Subarachnoid haemorrhage
Traumatic brain injury

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Why are ECHOs useful in acute ACS?

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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What are the GRACE and CRUSADE scores?

GRACE - predict risk of adverse outcome

CRUSADE - Risk of major bleeding during hospital admission following ACS

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

If presenting within 12 hours - PCI or fibrinolysis

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

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

Also give GTN and morphine PRN, may need anti-emetics too.

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What are the typical indications for fibrinolytic therapy?

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

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What is given alongside fibrinolytic therapy for STEMI?
Also the treatment for NSTEMI/ACS

Aspirin 300mg loading dose AND
Clopidogrel 300mg loading dose/ticagrelor 180mg loading dose AND
Antithrombin therapy: LMWH, unfractionated heparin or fondaparinux

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Describe the repercussion flow diagram for a patient with a STEMI

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

What are the absolute contraindications for fibrinolytic therapy?

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

What are the relative contraindications for fibrinolytic therapy?

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

What may suggest that fibrinolytic therapy has failed and now the need for resuce PCI?

Record ECG 60-90mins post.

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

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

- SC LMWH therapeutic dose 12hr or Fondaparinux OD - Aspirin 300mg loading then 75mg daily PLUS ONE OF - - Clopidogrel 300mg (or 600mg loading) then 75mg daily - Prasugrel 60mg then 10mg daily - Ticagrelor 180mg then 90mg BD Can consider glycoprotein IIb/IIIa inhibitor

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

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

How quickly should a patient with an NSTEMI/high risk unstable angina (high grace/ecg changes) have coronary angiography?

Within 72h of presentation

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

AF - indicate left ventricular failure Bradycardia - posterior or inferior MI due to SA node dysfunction | AV block - inferior AMI

How should AV block (causing bradycardia) in context of ACS be managed?

Treat bradycardia with atropine Consider temporary pacing if this fails PCI typically resolve heart block

What are the complications of ACS?

Arrhythmia Heart Failure Cardiogenic Shock

How can cardiogenic shock due to ACS be managed?

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

What are some other causes of sudden cardiac death and how do they cause cardiac arrest? (8 causes)

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

What % of people survive CPR in hospital and community respectively

Hospital -24% Community 9%

What are the 4 key non-technical skills

Situational awareness Decision-making Teamwork and leadership Task management

Causes of airway obstruction

Mostly neuro due to loss of reflexes - Cerebral oedema Hypercapnia Medication - alcohol, anaesthetic etc Others - Infection - epiglottitis and anaphylaxis Trauma - swelling, vomit or blood

Causes of breathing failure

Fractured ribs Pneumothorax ARDS Infection Opioids Pulmonary oedema Neuro - GBS, MS, MND

Causes of circulatory failure

Tamponade Thrombosis Arrhythmia Electrolyte abnormalities Valve disease Medication - tricyclics, digoxin Hypothermia Electrocution

4 features that indicate a high probability of arrhythmic syncope

In a supine position During or after exercise No or brief prodromal symptoms Repeated episodes FH of cardiac sudden death

What is crescendo angina

Angina on exertion occuring with increased frequency over a number of days and provoked by less exertion - type of unstable angina

What is shown on an ECG from a massive PE

Major PE - t wave inversion in V1-V4.

Other causes of raised troponin

Renal failure PE Aortic dissection CKD Myocarditis CHF Arrhythmias - rate-related Sepsis

Secondary prevention for ACS rx (8 things)

ECHO for HF and valve disease Low dose aspirin Antiplatelet - clopidogrel or ticagrelor If AF - DOAC over aspirin Beta blocker if even ifnot tachycardic Statin - high dose Lifestyle advice Antihypertensive

How is CHF managed

Loop diuretic - furosemide GTN ACEI Beta blockade - chronic not acute If LVEF dysfunction - spironolactone

What is Sudden arrhythmc death syndrome (SADS)

When sudden death occurs and there is no structural or molecular abnormalities seen on autopsy then could be an "electrical" fault and thus possibly inherited.

Ways to prevent SADS

Usually a defib inserted.

3 main things to do at start of cardiac arrest

Chest compressions Get defib on Get airway in and bag valve mask

What is waveform capnography for

Confirming tracheal tube is in patients airway, can monitor CPR quality.

How often should a rhythm check be done

Every 2 minutes

How is a respiratory arrest identified and managed (not breathing but has pulse)

Airway - might not tolerate but try anyway Breathing - bag valve mask approx 10/min Circulation - check pulse every minute and CRT If lose pulse - start CPR

If VT or pVF what to do first after CPR started and defib and airway sorted

3 stacked shocks then back to 2 mins of cpr and consider adrenaline etc