Bradycardia

Bradycardia is present when the ventricular rate is too slow. General guidelines are:

• Dog (< 20 kg) ≤ 70 bpm
• Dog (> 20 kg) ≤ 60 bpm
• Cat ≤ 100 bpm

Sinus bradycardia:

Etiology:

1. Enhanced parasympathetic tone as with:
   • Increased respiratory effort as with respiratory disease.
   • Gastric irritation.
   • Increased CSF pressure.
2. Hypothyroidism
3. Hypothermia
4. Hyperkalemia
5. Hypoglycemia
6. Drug therapy

Consequence: profound bradycardia will cause weakness, hypotension, syncope

Therapy:

1. Treat the underlying cause of the bradycardia
2. Atropine may abolish the bradycardia