Peri-arrest arrhythmias

Question 1

Which adverse features when found with an arrhythmia indicate the need for urgent treatment?

Answer 1

• Shock (hypotension, signs of shock)
• Syncope
• Heart failure (APO/RHF)
• myocardial ischaemia
• extremes of HR

Question 2

When does a synchronized shock deliver a shock?

Answer 2

synced with the R wave

worst is a shock on the T wave - “R on T” -leads to VF

Question 3

what energies should be used for broad complex tachy? AF, narrow complex, flutter?

Answer 3

broad+AF = 120-150
narrow+fluter= 70-120

Question 4

pad position for synced cardioversion of AF/flutter?

Answer 4

AP if possible

Question 5

If there are adverse features and the first three shocks fail to terminate the arrhythmia what should be done?

Answer 5

amiodarone 300mg over 10-20 min and further shocks

can follow with maintenance infusion of amiodarone 900mg over 24hours

Question 6

treatment for broad-complex tachycardia?

Answer 6

can be ventricular in origin or supraventricular with aberrancy (AF+BBB). either way if unstable then sync shock

if stable take 12 lead

if regular and thought to be VT then amiodarone, if thought to be supraventricular + aberrancy treat as narrow complex

if irregular seek cardio help, could be AF with aberrancy (Tx as narrow), could be AF with WPW (consider amiodarone), polymorphic VT (torsades). if torsades cease all QT prolonging agents, correct electrolytes and give 2g Mg IV over 10min and get help. Amiodarone is much less likely to cause torsades compared to other QT prolonging drugs

Question 7

treatment for narrow-complex tachycardia?

Answer 7

12 lead
regular could be sinus tachy, atrioventricular nodal re-entry tachy (AVNRT) (most common), atrioventricular re-entry tachycardia (AVRT) (WPW) AVNRT and AVRT are usually benign but can cause symptoms, flutter (2:1)

irreg could be AF, flutter with variable block, multifocal atrial tachycardia

regular Tx
if unstable - shock. can do vagal maneuvers or adenosine while preparing for shock.
if stable - vagal, adenosine 6mg, 12mg, 12mg (with flush into large IVC in large vein), warn pt. if fails to terminate this is likely flutter or adenosine is given too slowly or too peripherally. if adenosine doesnt work or is contraindicated can give verapamil 2.5-5mg IV over 2 min

irreg Tx
if unstable - anticoag (clex/hep) and shock
if stable can:
- rate control
- chemical cardioversion
- electrical cardioversion
- treatment to prevent complications 

if AF >48hrs need to be fully anticoag before shock and/or TOE excludes atrial thrombus. (can still do it if needed, give something tho).

After shocking AF need anticoag for minimum 4 weeks, often longer

Rate with IV/oral metoprolol, can use dig in HF, amiodarone, diltiazem, flecanide (seek help first - bad with HF/IHD/prolonged QT)

Question 8

What should be done if there is a rapid narrow complex tachycardia with impaired CO, no pulse, impaired consciousness?

Answer 8

Treat as PEA and start CPR

this is an exception to the non-shockable limb of ALS as this is likely to be treated with DC cardioversion

Attempt to deliver a 200J synchronized shock if possible, if not able to sync deliver a shock as normal in ALS

Question 9

Causes of bradycardia

Answer 9

physiological - athletes, sleep
cardiac origin- AV block, sinus node disease, post-cardiac surg, MI
non-cardiac origin - vagal, hypothermia, hyperkalaemia, haemochromatosis, rheumatic fever, hypothyroidism
drugs- beta blockers, diltiazem, dig, amiodarone

Question 10

Treatment of bradycardia

Answer 10

if adverse features give 500-600mg atropine IV, if no response can give up to 3mg, can pace or can use alternative drugs such as isoprenaline or adrenaline (if pacing or running other infusions arrange transvenous pacing)

if no adverse features, is there a risk of asystole? (recent asystole, mobitz II, CHB with broad QRS, ventricular pauses >3s) if yes treat as above, if no continue to observe