Arrhythmias

Question 1

What are the four possible cardiac arrest rhythms?

Answer 1

shockable - ventricular tachycardia and ventricular fibrillation
non-shockable - pulseless electrical activity and systole

Question 2

What is a narrow complex tachycardia and when does it occur?

Answer 2

fast heart rate
QRS complex <0.12seconds
atrial flutter
sinus tachycardia
SVT
AF

Question 3

What is broad complex tachycardia and when does it occur?

Answer 3

fast heart rate
QRS complex >0.12 seconds
ventricular tachycardia/ unclear cause
polymorphic ventricular tachycardia
AF with bundle branch block
SVT with bundle branch block

Question 4

What is the treatment for a patient who has life threatening features of cardiac arrest?

Answer 4

synchronised DC cardioversion
under sedation or general anaesthetic
if initial DC shocks are unsuccessful, add IV amiodarone

Question 5

What are ventricular ectopics?

Answer 5

premature ventricular beats
felt as if heart is skipping a beat
caused by random electrical discharges outside of the atria

Question 6

What is the difference between 1st and 2nd degree heart block in terms of ECG readings?

Answer 6

in 1st degree every P wave is followed by a QRS complex
in 2nd degree the P waves are not followed by a QRS complex

Question 7

Mobitz type 1 and 2 are considered which degree of heart block?

Answer 7

2nd degree heart block

Question 8

What is the pathophysiology behind mobitz type 1? And mobitz type 2?

Answer 8

type 1:
the conduction through the atrioventricular node takes progressively longer until it finally fails
then resets and cycle restarts
type 2:
there is intermittent failure in the AV node

Question 9

How do you identify mobitz type 1 on an ECG?

Answer 9

increasing PR interval until a P wave is not followed by a QRS complex
then it returns to normal

Question 10

How do you identify mobitz type 2 on an ECG?

Answer 10

absence of QRS complexes following P waves
2 or 3 P waves: 1 QRS

Question 11

What is third degree heart block?

Answer 11

complete heart block
no relationship between P and QRS
significant risk of asystole

Question 12

What are the potential causes of bradycardia?

Answer 12

medications e.g., beta blockers
heart block
sick sinus syndrome (conditions that cause dysfunction of the Sino-atrial node)

Question 13

What is asystole and who is at risk?

Answer 13

absence of electrical activity in the heart results in cardiac arrest
risks:
- previous asystole
- mobitz type 2
- third degree heart block
- ventricular pauses >3 secs

Question 14

How do you treat asystole?

Answer 14

1st line = IV atropine
alternatives = adrenaline, temporary cardiac pacing, permanent implantable pace makers