Arrhythmias

Question 1

Atrial fibrillation

Answer 1

Irregularly irregular QRS complexes
Absent P waves
Chaotic isoelectric baseline
QRS<120ms
Fibrillatory waves

Question 2

Atrial flutter

Answer 2

regular sawtooth-like atrial flutter F waves with P wave after P wave

Question 3

First degree AV block

Answer 3

Delayed AV conduction through AV node but every atrial impulse leads to ventricular contraction

PR interval > 0.2s

Question 4

Mobitz type 1/ Wenckebach

Answer 4

Atrial input becomes weaker until it doesn’t pass through AV node.

Increasing PR interval culminating in a dropped QRS complex, before PR interval resets.

Question 5

Mobitz type 2

Answer 5

Disease of His-Purkinje system causes intermittent failure of AV conduction.

Intermittently dropped QRS complex but constant PR interval

Question 6

Third degree AV block

Answer 6

Complete heart block. Associated with bradycardia, hypertension, apnoea.

P wave and QRS complex completely dissociated

Question 7

Left bundle branch block

Answer 7

Deep S wave in V1, tall late R wave in V6

Question 8

Right bundle branch block

Answer 8

Wide, slurred S wave in V6, tall late R wave in V6

Question 9

Wolff Parkinson White

Answer 9

Short PR
Slurred upstroke (delta wave)
Wide QRS