Chapter 4 Causes of cardiac arrest

Question 1

What is crescendo angina?

Answer 1

Angina on exertion, occurring with increasing frequency over a few days, provoked by progressively less exertion

Question 2

What is stable angina?

Answer 2

Exertional chest pain that is relieved promptly with rest.

Does occur at rest

Question 3

in unstable angina, the ECG may

Answer 3

Be normal
Show evidence of myocardial ischaemia (ST depression)
Non-specific abnormalities (TWI’s)

Question 4

In patients with ACS but without chest pain, what is the predominant symptom?

Answer 4

Breathlessness

Question 5

Other than chest pain, what are the features of aortic dissection?

Answer 5

Hoarse voice
Swallowing difficulty
Back pain
Hypotension
Loss of a peripheral pulse/asymmetrical pulses
Neurologicial signs
Aortic murmur

Question 6

A patient has acute chest pain, marked hypotension, no ECG evidence of AMI. What differential would you consider?

Answer 6

Aortic dissection

Question 7

A patient has a good history and typical ECG evdience of a STEMI. Should you delay reperfusion to investigate further for PE or aortic dissection?

Answer 7

No. Only delay if there is strong evidence pointing towards these differentials.

Question 8

How long do you have to provide PCI for a STEMI?

Answer 8

120 minutes

Question 9

What has a worse prognosis: anterior, inferior or lateral infarction?

Answer 9

Anterior. Large area of left ventricle is damaged.

Question 10

What vessel is occluded in an inferior infarction (II, III, aVF)

Answer 10

Right coronary artery (sometimes circumflex artery)

Question 11

What vessel is occluded in a lateral infarction ( V5, V6, I, aVL)

Answer 11

Circumflex or diagonal of the LAD

Question 12

What vessel is occluded in a posterior infarction?

Answer 12

Right coronary artery (circumflex in a left dominant person)

Question 13

What are the ECG findings of a posterior infarction?

Answer 13

Reciprocal ST depression in anterior leads

Dominant R wave V1, V2 reflects posterior Q wave

Question 14

What are of area of myocardium is affected in a posterior infarction?

Answer 14

Posterior LV

Posterior septum

Question 15

How do you confirm a posterior infarction

Answer 15

Posterior ECG leads (V6, V7, V8, V7, V9, V10). Continuate around left axilla to the right of the spine

Question 16

What type of/areas of infarction are at increased risk of ALSO having a right ventricle infarction?

Answer 16

1/3 of inferior and posterior STEMI’s involve the RV

Question 17

How to use diagnose a right ventricle infarction?

Answer 17

May see STE in V1
Do right sided ECG (different to posterior ECG)
V1R to V6R leads added on
Suspect if patient has fluid responsive hypotension or raised JVP but no pulmonary oedema

Question 18

What ECG changes can be seen in SAH or traumatic brain injury?

Answer 18

Lots.

ST elevation, depression, TWI.

Question 19

Can troponin be elevated with PE, aortic dissection or myocarditis, chronic heart failure, chronic renal disease or acute sepsis?

Answer 19

yes

Question 20

How often is S1-QTIII (Dominant S wave in Lead I, Q wave + TWI lead III) seen in PE?

Answer 20

15%

Question 21

Is there benefit from reperfusion therapy after 12 hour?

Answer 21

Little to none. Can consider if ECG evidence of ongoing ischaemia.

Question 22

What is the common action of clopidogrel, ticagrelor and prasugrel?

Answer 22

All block ADP receptor on platelets.
In STEMI
Clopidogrel 300 - 600mg or
Ticagrelor 180mg or
Prasugrel 60mg (not if > 75, < 60kg or hx bleeding or stroke)

Question 23

What are the indications for fibrinolysis?

Answer 23

Presentation within 12 hours of onset of chest pain suggestive of AMI, and:

• ST elevation > 2mm in 2 adjacent chest leads or,
• ST elevation > 1mm in 2 adjacent limb leads, or
• Dominant R wave and ST depression V1 - V3 (posterior infarction)
• New onset LBBB

Question 24

When giving fibrinolysis, what other drugs need to be given for treatment of STEMI?

Answer 24

Aspirin 300mg
Clopidogrel 300 - 600mg (or ticagrelor 180mg)
Antithrombin therapy (enoxaparin or heparin or fondaparinux)

Question 25

What are the absolute contraindications to fibrinolysis?

Answer 25

1) Previous haemorrhagic stroke 2) Ischaemic stroke with 6 months 3) Central nervous system damage or neoplasm 4) Major surgery, head injury or other major trauma with 3 week 5) Active internal bleeding (menses excluded) or GI bleeding within past month 6) Known or suspected aortic dissection 7) Known bleeding disorder

Question 26

On the ECG what is suggestive of fibrinolytic therapy failure?

Answer 26

Failure of ST segment elevation to reduce by more than 50%

Question 27

What is 'rescue angioplasty'?

Answer 27

PCI post fibrinolytic therapy. | Improves survival and reduces heart failure in those with failed fibrinolytic therapy

Question 28

What are the two immediate treatment outcomes in ACS?

Answer 28

1) prevent new thrombus formation | 2) reduced myocardial oxygen demand

Question 29

How do you prevent thrombus extension in ACS?

Answer 29

Asprin Clexane or heparin And usually ADP receptor blocker if going for angiography

Question 30

How do you reduced myocardial oxygen demand?

Answer 30

``` Beta blocker ( or non-dihydropyridine calcium channel blocker) GTN +/- infusion if persistent pain Consider early ACEI introduction ``` Treat heart failure or tachyarrhythmia promptly

Question 31

A patient has reperfusion therapy for ACS, then has an accelerated idioventricular rhythm. Does this require treatment?

Answer 31

No. Is usually transient and no treatment needed.

Question 32

What are bradyarrhthmias common with inferior infarctions?

Answer 32

Right coronary artery occlusion, loss of blood supply to SA and AV nodal arteries

Question 33

A patient has an inferior infarctin and develops heart block. What is the first thing you can to do treat them?

Answer 33

Atropine

Question 34

What is the only lead that looks directly at the right ventricle?

Answer 34

V1

Question 35

In a patient with inferior STEMI (RCA occlusion), what suggest a right ventricular infarction?

Answer 35

ST elevation in V1 ST elevation in V1 and ST depression in V2 (highly specific for RV infarction) Isoelectric ST segment in V1 with marked ST depression in V2 ST elevation in III > II Confirmed by presence of STE in right sided leads ( V3R, V6R)

Question 36

How many STEMIs are complicated by an RV infarction?

Answer 36

40% | Isolated RV infarction is rare though

Question 37

Why is diagnosing an RV infarction important?

Answer 37

They are very pre-load sensitive due to poor RV contractility. Can develop severe hypotension in response to nitrates or other pre-load reducing agents. Hypotension in RV infarction is treated with fluid loading. Nitrates contraindicated.

Question 38

A patient with ACS goes into cardiogenic shock. How would you treat?

Answer 38

``` Consider frusemide (caution right ventriclular infarction) BIPAP/ CPAP Oxygen Noradrenaline for vasopressor Dobutamine as inotrope (B1 > B2 > Alpha) ```

Question 39

A patient with ACS develops cardiogenic shock. Do they have a good chance of surivial?

Answer 39

No. High mortality. May be reduced if urgent revascularisation provided.

Question 40

What are the electrical/ionopathies (ECG findings) that predispose someone to sudden cardiac death (predisposes to VF & VF)?

Answer 40

1) Long QT syndrome (inherited) 2) Acquired long QT 3) Brugada syndrome 4) Short QT syndrome (QTc < 340 + symptoms/syncope) 5) Catecholaminergic polymorphic ventricular tachycardia 6) Wolf-parkinson-White syndrome (risk of rapid AF transmitted to ventricles) 7) High grade AV block

Question 41

What are thy structural heart disease predisposing to suddent cardiac death?

Answer 41

1) Arrhythmogenic right ventricular cardiomyopathy (ARVC) 2) Hypertrophic cardiomyopathy (HCM) 3) Severe aortic stenosis 4) Dilated cardiomyopathy 5) Ischaemic/coronary heart disease 6) Anomalous coronary artery anatomy (congenital) 7) Other myocardial disease ( HTN, sarcoid, ect)