Equine Cardiology

Question 1

What is the most common non-pathologic heart arrhythmia in equine patients?

Answer 1

2nd Degree AV-Block

Question 2

What clinical signs are associated with a 2nd Degree AV-Block in horses?

Answer 2

A slow-to-normal heart rate

Question 3

What do we expect to see on an ECG of a horse with a 2nd Degree AV-Block?

Answer 3

Some P Waves will not be followed by a QRS Complex.

Question 4

What treatment is indicated for 2nd Degree AV-Blocks in horses?

Answer 4

None - These are typically non-pathologic.

Question 5

What is the most common pathologic arrhythmia seen in horses?

Answer 5

Atrial Fibrillation

Question 6

What clinical signs are associated with atrial fibrillation in horses?

Answer 6

Normal to elevated heart rate
Exercise Intolerance
Poor Performance

The severity of these signs is dependent on the underlying pathology in the heart and can range from being near absent to severe.

Question 7

What treatment options do we have for horses presenting with Atrial Fibrillation?

Answer 7

None

Quinidine Sulfate

Electrical Cardioversion

Question 8

How would you treat a horse presenting with the arrhythmia shown below?

Answer 8

No treatment is necessary. 2nd Degree AV Blocks are the most common non-pathologic arrhythmia seen in equine patients.

Question 9

How would you treat a horse presenting with the arrhythmia shown below?

Answer 9

Treatment can differ between patients:

None - Benign neglect can be appropriate if clinical signs are minimal and it is a low-activity pasture animal.

Quinidine Sulfate - This is the standard medical therapy. It is often accompanied by side effects including Diarrhea, Colic, Laminitis, and Arrhythmias

Electrical Cardioversion - Recently documented in literature, not available in most places.

Question 10

What side-effects are associated with the use of Quinidine Sulfate?