Arrythmias Learning Outcomes

Question 1

Know normal sinus rhythm:

Answer 1

• Heart rate is between 60bpm and 100 bpm

- The ECG is normal with no depression or elevation

Question 2

Explain 1st, 2nd and 3rd degree heart block

Answer 2

All of these refer to electrical impulses which are blocked in the heart from atria to ventricles. (due to damage/fibrosis of conduction system)

1st - Disease of the electrical conduction system of the heart. The PR interval is lengthened to greater than 0.20s. No missing beats. Signal is delayed but still makes it to the ventricles. Patients are usually asymptomatic. Usually doesn’t require treatment

2nd - Split into Mobitz I, (PR interval progressively gets longer and longer until a QRS complex is missed - dropped beat) symptoms include syncope.
and Mobitz II, (QRS complexes are regularly missed) symptoms include dyspnoea, fatigue, syncope and chest pain

3rd - This is complete heart block. The electrical signal is completely blocked when moving from atria to ventricles. Therefore P waves and QRS complexes appear independently of each other. Symptoms include dyspnoea, severe chest pain, syncope and confusion

Question 3

Describe atrial fibrillation and flutter

Answer 3

Atrial fibrillation - Abnormal heart rhythm due to electrical impulses firing off from different places in the atria in a disorganised way

Atrial flutter - Atria contract at very fast rates and more often than the ventricles. So for example you may have 4 atrial beats for every ventricular beat