Arrhythmias

Question 1

What is the 6-step rule for suspected cardiac arrhythmia’s?

Answer 1

1. ABC, IV access, O2, Cardiac monitor (Min 3-lead ECG and continuous monitoring), Take bloods
2. Defibrillator to the bedside
3. Unstable or stable? Basic obs, history, exam
4. Are there p- waves?
5. Is the rate regular or irregular?
6. Is the QRS complex narrow or wide?

Question 2

What are signs of instability?

Answer 2

Sweating
Confusion
Reduced GCS
Hyperventilation 
Low BP
Tachycardia
Pulmonary oedema

Question 3

Why do you look for p-waves?

Answer 3

If p-waves are present

Likely sinus rhythm

Question 4

What comprised the basic history?

Answer 4

Chest pain
SOB
Previous cardiac history: IHS, arrhythmia

Question 5

What are you looking at more specifically with regards to p-waves?

Answer 5

12 lead ECG and rhythm strip

Is there a p wave before every QRS?

• lots of p waves and few QRS = atrial flutter
• absent = AF

Is the axis of the P wave normal?
- upright in Lead II, can be neg in aVR

Question 6

What rhythm is seen in AF?

Answer 6

Irregularly irregular

Different R-R intervals

Question 7

What does an irregular rhythm mean?

Answer 7

Arrhythmia originates above AV node
Supra-ventricular tachycardia
VT can not be irregular

Question 8

What defines a narrow QRS complex and what does this mean?

Answer 8

Narrow < 0.12s (3 little squares)

Indicates arrhythmia originates above AV node

Question 9

What do different QRS complezes men

Answer 9

Narrow regular - above AV node

Narrow irregular - above AV node

Wide regular - below AV node, VT

Wide irregular - above AV node

Question 10

What Narrow regular

Answer 10

SVT

• AV nodal re-entry tachycardia
• Atrial flutter with regular block
• WPW

Question 11

What is the acute treatment of SVT?

Answer 11

Block AV node
Adenosine
6mg, 12mg
Warn patient, causes bronchoconstriction

CI: Asthma or 2nd/3rd degree HB

Short acting: shows underlying rhythm

Question 12

What is definitive treatment for SVT?

Answer 12

Flecanide
Betablockers
Amiodarone

DC cardioversion if unstable
- needs to be synchronised to R-wave to avoid ventricular fibrillation
(100J, 200J or 360J)

Question 13

What causes Narrow irrregular QRS complexes?

Answer 13

AF
A-flutter
Atrial tachy

Question 14

What is wide and regular?

Answer 14

V-tach
WPW
SVT w/ BBB

Question 15

How do you treat wide and regular

Answer 15

If in doubt treat as VT esp if unstable
More serious

Hx of IHD
Poor LV function
Haemodynamically unstable
Looks similar across leads

Question 16

Wide, regular QRS treatment?

Answer 16

Check U+E
DC cardioversion if unstable
Synchronicity does not matter - originates below AV node

Question 17

What treatment should be avoided for wide irregular QRS?

Answer 17

Torsades de pointes
- avoid amiodarone

WPW w/ pre-excited AF
- do not use AV nodal blockers e.g. betablockers and verampil

Question 18

What is a quick way to assess axis?

Answer 18

Lead I and aVF - away from eachother = left axis deviation

Lead I and aVF - towaRds = right axis deviation

Question 19

What is the treatment for fast AF (stable)?

Answer 19

Rate control - betablocker

Anti-coag - LMWH

Question 20

How do you assess stroke risk?

Answer 20

CHADSVASc score

But not in acute setting

Question 21

When do you seen hypotension in cardiogenic shock?

Answer 21

Late sign

Sign of instability

Question 22

What would show some signs of above AV and some below AV causes?

Answer 22

WPW w/ pre-excited AF
Young male
Broad, tachy, irregular rhythm

Need to cardiovert
AVOID beta-blockers, cannot slow AV node even more

Question 23

Unstable, regular rhythm, p-waves present: likely diagnosis?

Answer 23

Ventricular tachycardia