Bradyarrhythmia's

Question 1

Describe features of first degree heart block, causes and management

Answer 1

• PR prolongation >200ms
• Caused by high vagal tone (athletes), inferior MI, hyperkalaemia, beta blockers, digoxin
• Benign so doesn’t need treated

Question 2

Describe features of Morbitz type I heart block, causes and management

Answer 2

• Progressive lengthening of PR till P wave fails to conduct QRS
• Causes: MI, drugs (BBs, CCBs, digoxin), professional athletes, myocarditis
• Generally asymptomatic and doesn’t need treatment. If symptomatic then stop precipitating drugs, if adverse features then Atropine.

Question 3

Describe features of Morbitz type II heart block, causes and management

Answer 3

• Regular non conducted P waves
• Causes: MI, surgery, autoimmune diseases (SLE, sclerosis, myocarditis), fibrosis, infiltration (sarcoid, haemochromatosis), meds (BBs, CCBs, dig)
  -High risk of developing complete heart block so they require a permanent pacemaker

Question 4

Describe features of third degree/complete heart block, causes and management

Answer 4

• Complete dissociation between P waves and QRS.
• Causes: MI, drugs (BBs, CCBs, adenosine), idiopathic fibrosis
• Permanent pacemaker and acute bradycardia guideline

Question 5

What are the adverse signs of bradycaria?

Answer 5

• Shock (hypotension, pallor, sweating, cold, clammy, confusion)
• Syncope,
• Myocardial ischaemia
• Heart failure

Question 6

What is the management of Bradycardia with adverse signs?

Answer 6

First line = 500mg atropine. This can be repeated up to 3mg
Second line = transcutaneous pacing or IV isoprenaline/adrenaline

Question 7

What are some potential risk factors for asystole?

Answer 7

• Complete heart block with broad complex QRS
• Recent asystole,
• Morbitz type II AV block,
• Ventricular pause > 3 seconds