Interesting ECG 1

Interesting ECG 1





By Russel J Leadsom BVSc CertVC MRCVS

Signalment and history

A 9-year-old male crossbred dog presented with a recent history of exercise-induced syncope. Heart rate alternated between 130 bpm and 65 bpm, both with regular rhythms.

Echocardiography was unremarkable.


  • Intermittent second-degree 2:1 AV block with concurrent left bundle branch block.
  • The blocked P waves are indicated *.
  • The arrhythmia deteriorated to second-degree 2:1 AV block with periods of advanced 3:1 block, and increased frequency of syncopal episodes.
  • There was no response to atropine, and a pacemaker was fitted.
  • To date this dog has a healthy active life.

Leave a reply

  • Secured Payments
  • Mastercard
  • Visa
  • instant-eft
  • Payfast