Ventricular Tachycardia

Introduction

Ventricular tachycardia is a rhythm disturbance that produces a rapid, regular heart beat caused by continuous ventricular premature complexes (VPCs). It is a serious condition which has the capability of causing ventricular fibrillation and ultimately death. It is most likely to occur secondary to an existing abnormality in either the heart or the rest of the body.

It is particularly common in Dobermanns secondary to Dilated Cardiac Myopathy.

Causes

Significant myocardial damage to the heart or disease in other systems, Drug reactions, Hypoxia, Anaemia, Electrolyte and acid-base disturbances, etc.

Clinical Signs

On cardiac auscultation, heart rate is abnormally high and irregular. The dog may present collapsed and have signs of output failure.

Diagnosis

The condition can be diagnosed by ECG. The ECG shows wide and irregular QRS complexes, and P waves without QRS complexes following.

Treatment

The underlying cause should be identified and treated where possible.

Small Animals

Dog: lidocaine (1st line of treatment), quinidine or procainamide (2nd line of treatment)

Cat: propranolol (1st line of treatment), small dose of lidocaine (2nd line of treatment)

Large Animals

• Digitalis

• Quinidine Sulfate

• Magnesium Sulfate supplementation (used in horses)