ECG 18

Signalment: Twelve-year-old spayed female miniature schnauzer (Sophie)

Diagnosis: Episodes of collapse (6 episodes yesterday)

ECG on Presentation

Quiz

1. What is this dog's primary cardiac rhythm abnormality?

Atrial standstill

Asystole

Cardiac arrest

Sinus arrest

2. What is a general name for QRS complexes 3 and 6?

Premature complex

Escape complex (beat)

Bundle branch block

Funky

3. Where does the third QRS complex originate from?

Right atrium

Left atrium

AV node

Purkinje fibers (a ventricle)

4. Where does the sixth complex originate from?

Right atrium

Left atrium

AV node

Purkinje fibers (a ventricle)

5. What would lidocaine administration do to this dog?

Cure it

Improve its rhythm

Kill it

Make it seizure

Check Answer

Following Therapy

The dog had a permanent pacemaker implanted. The lead was placed in the apex of the right ventricle and the generator set to VVI mode. Notice the P waves (sometimes positive and sometimes negative) in the ST segment following each QRS complex. These are due to retrograde conduction through the AV node to the atria.