For some unknown reason, Kaya, a three-week-old miniature donkey was suffering from episodes of fainting. She was taken to her local veterinarian who performed a complete physical examination.
The vet soon discovered a systolic heart murmur. In addition, he could hear dropped heart beats that he believed were associated with the fainting.
After an electrocardiogram confirmed an abnormal heart rhythm, the veterinarian referred Kaya to the William R. Pritchard Veterinary Medical Teaching Hospital at UC Davis.
It was there that “Kaya” was seen by both the Large Animal Internal Medicine Department and the Cardiology Department.
They learned that not only was Kaya experiencing fainting episodes, but she was an unusually quiet baby donkey. She never bucked or played like a normal baby.
Upon further examination, the UC Davis veterinarians agreed with the diagnosis made by Kaya’s local vet. Kaya had both heart murmurs and an abnormal heart rhythm.
To understand the causes of these abnormal findings, the UC Davis veterinarians performed both an electrocardiogram (ECG) and an echocardiogram (cardiac ultrasound).
The ECG showed an abnormal rhythm (arrhythmia) consistent with third-degree AV block, which is a failure of the inherent pace-keeping mechanism of the heart.
The ultrasound showed that the mitral, tricuspid and aortic valves were slightly leaky but that the overall structure and size of the heart were normal.
Routine lab work ruled out infection or electrolyte disturbances as the underlying causes of the arrhythmia.
Given these findings, it was suspected that Kaya’s third-degree AV block might be congenital, meaning they were present at birth as a result of hereditary or environmental influences.
It was decided to give Kaya a pacemaker to treat the arrhythmia. However, there were important considerations for Kaya’s health regarding the placement of the pacemaker.
First, given Kaya’s age, it was likely that she would outgrow her pacemaker and that a second surgery would in all probability be required.
Secondly, the placement of the pacemaker was critical. The jugular vein used for the placement of the pacemaker could never be used to administer intravenous medications or to draw blood.
After careful consultation, Kaya was placed under general anesthesia and a pacemaker was installed. The evidence of the pacemaker’s success was seen immediately.
Little Kaya bucked for the first time that same evening!
It was six months later that Kaya returned for a second and larger pacemaker. This surgery and the placement of her second pacemaker was successful.
Kaya is a now a very happy, bouncing donkey !
Horse Report – School of Veterinary Medicine -UC Davis