BRADYCARDIA

Question 1

If the rhythm is sinus bradycardia, nodal bradycardia, first degree heart block, second degree heart block or an undifferentiated narrow complex bradycardia:

Answer 1

• Administer 0.6 mg of atropine IV. Administer further doses (without a
  maximum dose) as required if the bradycardia is responsive to atropine.
• Administer adrenaline IV (as above) if the bradycardia is unresponsive to atropine.
• Stop adrenaline administration and initiate pacing if the bradycardia is unresponsive to adrenaline IV.

Question 2

If the rhythm is third degree heart block or an undifferentiated broad
complex bradycardia:

Answer 2

• Initiate pacing.
• Stop pacing and administer adrenaline IV if the bradycardia is unresponsive to pacing:
  a) Administer an adrenaline infusion via an infusion pump. Start at a rate of 0.5 mg/hour and adjust the rate as required, or
  b) Place 1 mg of adrenaline into a 1 litre bag of 0.9% sodium chloride (1:1,000,000 solution):
  ū Administer as an infusion. Start at 2 drops/second and adjust the rate as required, or
  ū Administer a bolus of 0.01 mg adrenaline (10 ml) IV every 1-2 minutes as required.

Question 3

• Bradycardia in adults is most commonly caused by

Answer 3

Myocardial ischaemia, particularly when the SA node or AV node is ischaemic. Inferior myocardial ischaemia is much more likely to involve these nodes than anterior or anterolateral myocardial ischaemia.
ū Structural heart disease involving the sinoatrial node, atrioventricular node or the conduction system. This is most common in elderly patients.