Supraventricular Tachycardia

Small Animal: Common

Large Animal: Uncommon

a. Paroxysmal Atrial Tachycardia (PAT)=regular rapid atrial contractions arising from atrial tissue outside the SA node

b. Atrioventricular Junctional Tachycardia (AJT)=regular rapid atrial contractions arising from AV nodal tissue

c. Supraventricular Tachycardia a term used to include both PAT and AJT. Rapid premature beats occuring somewhere above the ventricles.

Causes

Result from pathological conditions in the cardiac atria, hypoxia, stress, digitalis toxicity, systemic hypertension etc.

ECG Appearance: Rapid heart rate, abnormal P wave (inverted) which can be preceded, be superimposed, or follow QRS complexes

Treatment

Small Animals

• Treat underlying cause

• Vagal manoeuvres (e.g. carotid sinus or ocular massage)

• Drug Treatment:

-If + for congestive heart failure treat with digoxin and other heart failure drugs

-If - for congestive heart failure treat with diltiazem, propranolol, or adenosine

• Avoid digoxin if a reentry mechanism is suspect in causing the supraventricular tachycardia

• Pacing methods

Large Animals

• Treat underlying cause

• Box rest with heart rate and rhythm monitoring

• If + for heart failure, give digoxin

• Vagal manoeuvres (e.g. carotid sinus or ocular massage)

• Quinidine sulfate