Chapter 4: Cardiac Causes of Cardiac Arrest Flashcards
How can acute coronary syndrome be split up?
ST elevated myocardial infarction
Non ST Elevated acute coronary syndromes:
- NSTEMI
- Unstable angina
What can be used to determine between STEMI and NSTEMI?
ST elevation or new LBBB = STEMI
Other ECG changes = NSTEMI/Unstable angina
How do you differentiate between unstable angina and NSTEMI?
Troponin release
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
Which groups of people may present with ACS less typically?
Females
Elderly
Diabetics
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
What ECG changes can an NSTEMI/unstable angina show?
Normal
ST Depression
Non specific abnormalities - t wave inversion
When is risk of progression from NSTEMI to full occlusion highest?
First few hours, days and months
What is there a substantial risk of in the acute phase of a STEMI?
VF
VT
Sudden death
What ECG changes may be seen in a STEMI?
ST elevation
New LBBB
Pathological q waves
T wave inversion
Hyperacute t waves (v early)
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
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
What is important to know about posterior MI’s?
Must confirm with posterior leads
Risk of bradycardia as sinoatrial node may be affected
What other conditions can cause ST elevation or depression, not related to the heart?
Subarachnoid haemorrhage
Traumatic brain injury
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
What are the GRACE and CRUSADE scores?
GRACE - predict risk of adverse outcome
CRUSADE - Risk of major bleeding during hospital admission following ACS
Within what time frame should reperfusion be post STEMI without delay?
If presenting within 12 hours - PCI or fibrinolysis
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.
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
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
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
