Module 1
Topic 5
Lesson 17

Infra-hisian block

Helmut Pürerfellner
EHRA President 2025-26

What will you learn?

  • what happens with conduction signal in type 2 second degree AV block
  • how prolonged HV interval looks like
  • how to recognise ventricular escape rhythm

WARNING! Let's see if you are ready to rescue the patient when unexpected happens. Be sure that it's more common than you think.

About this scenario

  • Prolonged HV interval indicates infrahisian conduction abnormality.
  • During the non-conducted P wave both an A as well as an H can be expected on the HIS catheter.
  • In such patients you can expect spontaneous or mechanically induced complete AV block.
  • 3rd degree AV block can be recognised by A V dissociation (V is independent from A)
  • In case of AV block (or any other asystole) an escape rhythm can be observed. Ventricular escape rhythm is characterised by a bright QRS morphology and rate about 40bpm.
  • To avoid asystole related symptoms you should start ventricular pacing i.e. RVA. Atrial pacing will not help due to obvious reasons :)