ECG

Question 1

What makes a rhythm ‘SINUS’?

Answer 1

50-100BPM HR
P wave after every QRS complex
POSITIVE P WAVE IN LEAD 2
CONSTANT PR Interval

Question 2

Causes of bradycardia?

Answer 2

Sinus Brady
Sinoatrial block 
SA arrest/inhibition 
2nd/3rd Deg AV Block 
Sinoatrial node dysfunction/Sick Sinus Syndrome (Symptomatic SND)

Question 3

Causes of Tachycardia - NARROW QRS?

N.B. - Rarely cause circulatory compromise or collapse

What is Narrow QRS Duration?

Answer 3

Sinus Tachy
SA re-entry Tachy 
AF
Atrial Flutter
Multifocal Atrail Tachy 
AVNRT 
AVRT(WPW)

QRS duration <0.12s

Question 4

Causes of Tachycardia - BROAD QRS?

What is Wide QRS Duration?

Answer 4

Ventricular Tachy
Sinus Tachy with LBBB

QRS complexes become wide due to abnormal ventricular depolarisation

QRS duration >=0.12s

Question 5

Which leads should P-Wave always be positive in?

Answer 5

LEAD 2, 3 AND AVF

Question 6

What is the Normal P-wave duration, amplitude and PR interval?

Answer 6

<0.12 (all leads)

Question 7

QRS Complex Checklist?

Answer 7

Duration <0.12s (0.07-0.10)
At least 1 limb lead with R-Wave amplitude >5mm + 1 Chest lead with R-Wave amplitude >10mm [Low Voltage]
R wave progression present (V1-V6)?
Pathlogical Q waves?
Normal electrical axis? (Between -30 to 90 deg)

Question 8

What is the amplitude of QRS would mean High voltage?

Answer 8

S-Wave V1 or V2 + R-Wave V5 >35mm

Question 9

Reasons for a wide QRS?

Answer 9

LBBB
RBBB
Hyperkaleimia 
Class 1 Antiarrhytmic drugs
TCA antidepressants 
Articifical ventricular pacemaker
WPW (Pre-excitation)