Cardiovascular disease is not common in horses in the same way that it is in people.

However, horses can suffer from arrhythmia’s, which can cause a loss of performance. This is when the heart beat becomes irregular and the heart is not contracting in an effective way. Many arrhythmia’s are picked up when we listen to the heart with a stethoscope, but an ECG is needed to confirm the diagnosis and choose further treatment. An ECG traces the electrical activity of the heart.

The most common arrhythmia in the horse is called an AV-block (atrio-ventricular block). This is a normal variation and nothing to worry about. It is commonly heard in a lot of fit horses and goes away with exercise.

Atrial fibrillation is the most common rhythm abnormality seen in horses. This may be picked up on at a routine check, or during an investigation for poor performance. Most of these horses do not have underlying heart disease can undergo medical treatment to convert the heart back to a normal rhythm. 

Less commonly other arrhythmia’s occur secondary to an illness (colic/infection) or underlying heart disease. These can be more serious and require immediate intervention.