Chapter 11: Peri-Arrest Arrhythmias

Question 1

If a patient has a tachyarrhythmia with adverse features (unstable and at risk of deterioration), what do you do?

Answer 1

1. Synchronised Cardioversion
2. Amiodarone 300mg IV (if not responding) over 10-20 mins then 900mg infusion over 24hr

Question 2

What does a synchronised cardioverter synchronise the shock with?

Answer 2

1. The R wave

An unsynchronised shock can coincide with the t wave and cause VF

Question 3

What energy to use for synchronised cardioversion of - Broad-complex tachyarrhymthia, AF & atrial flutter:

Answer 3

1. Broad complex tachycardia - 120-150J and then increase
2. Atrial flutter - 70-120J and increase as req.
3. AF - max output

Question 4

If a patient has a broad complex tachyarrhythmia with adverse features, what do you do?

Answer 4

1. Synchronised cardioversion

Question 5

If a patient has a broad complex tachyarrhythmia without adverse features that is regular, what do you do?

Answer 5

1. May be VT or SVT + BBB

If VT - amiodarone 300mg IV over 20-60 mins then 900mg over 24hr

If SVT + BBB - Rx as regular narrow complex tachycardia

Question 6

If a patient has an irregular broad complex tachycardia and is stable, what could it be and what do you do?

Answer 6

1. AF with BBB - Rx as for narrow complex tachy
2. Pre-excited AF - consider Amiodarone
3. Polymorphic VT - Call for expert help

Question 7

How do you treat torsades du pointes?

Answer 7

1. Stop drugs that prolong QT
2. Correct electrolytes - esp. hypoK
3. MgSO4 2g IV over 10 mins
4. Get expert help!
5. If adverse features - synchronised cardioversion
6. If pulseless - defibrillation

Question 8

How are patients with regular narrow complex tachycardias without adverse features treated?

Answer 8

1. Vagal manoeuvre
2. Adenosine 6mg > 12mg > 12mg
3. Monitor ECG

Question 9

What adverse features would warrant synchronised cardioversion in tachyarrhythmia?

Answer 9

1. Shock
2. Syncope
3. MI
4. HF

Question 10

If a regular narrow complex tachycardia doesn’t respond to adenosine, what should be done?

Answer 10

1. Control rate with BB - possible atrial flutter

Question 11

If a patient has an irregular narrow complex tachycardia but no adverse features, what should be done?

Answer 11

1. Rate control - BB or diltiazem (digoxin if HF)
2. Assess thromboembolic risk and consider anticoagulation

Question 12

What can be given for a regular narrow complex tachy if adenosine is CI or fails to terminate?

Answer 12

1. Verapamil 2.5-5mg IV over 2 mins

Question 13

If a patient has a very rapid narrow complex tachy to the point a pulse is impalpable what should you do?

Answer 13

1. Synchonised DC cardiovert

Exception to normal as PEA is non-shockable

Question 14

If a patient has had AF for >48hr what should you do?

Answer 14

1. Rate control
2. Anticoagulant prophylaxis for 3wk before cardioversion
3. Can do echo to R/O atrial thrombi and then cardiovert if req.

Question 15

What should be done in patients with AF >48 hrs with urgent need for cardioversion?

Answer 15

1. LMW heparin in therapeutic dose or IV bolus unfractionated heparin
2. Maintain APTT 1.5-2x reference
3. Continue heparin Rx
4. Cardiovert pt.
5. Start oral anticoagulation Rx

Question 16

What agents can be used for chemical cardioversion of AF?

Answer 16

1. Flecainide
2. Propafenone
3. CI - then use amiodarone 300mg 20-60min then 900mg over 24hr

CI in HF, LV impairment, IHD or prolonged QT

Question 17

What can cause bradyarrhythmia?

Answer 17

1. Physiological - athletes, during sleep
2. Cardiac - heart block, sinus node disease
3. Non-cardiac - vasovagal, hypothermia, hypothyroid, hyperK
4. Drug - Amiodarone, Beta blocker, Diltiazem, Digoxin,

Question 18

If a patient with bradyarrhythmia has adverse features, what is the management?

Answer 18

1. Atropine 500mcg IV - repeat up to total 3mg dose (6 doses)

Question 19

If atropine doesn’t resolve a bradyarrhythmia with adverse features, what can be done?

Answer 19

1. Transcutaneous pacing OR
2. Isoprenaline 5mcg/min IV
3. Adrenaline 2-10mcg/min IV

Question 20

What alternative drugs can be considered for bradyarrhythmia?

Answer 20

1. Aminophylline 100-200mg slow IV infusion - due to acute inferior MI, spinal cord injury or cardiac transplant
2. Dopamine 2.5-10mcg/min
3. Glucagon - if caused by beta blocker or Ca2+ blocker
4. Glycopyrrolate - instead of atropine

Question 21

What should be done if a patient with bradyarrhythmia is displaying no adverse features?

Answer 21

1. Assess for risk of asystole:
   - Recent asystole
   - Mobitz II
   - Complete heart block with broad QRS
   - Ventricular pause >3s
2. If risk - Atropine or transcutaneous pacing or adrenaline
3. If no risk - continue observations

Question 22

When should you not give atropine

Answer 22

1. Cardiac transplants - hearts denervated so don’t respond to vagal blockade
2. May lead to paradoxical sinus arrest or high grade AV block

Question 23

When is transcutaneous pacing used for bradycardia?

Answer 23

1. No response to Atropine or CI
2. Not due to beta blocker/ca2+ blocker - glucagon
3. Not due to digoxin - digoxin antibody

Should be initiated immediately if indicated

Question 24

When is temporary transvenous pacing considered?

Answer 24

1. Documented recent asystole
2. Mobitz type II
3. Complete AV block