Accelerated Idioventricular Rhythm Associated With Isoflurane Administration in a Foal: A Case Report.

This research article discusses a case study of a 2-day-old filly (young female horse) with abdominal issues, who developed an unusual heart rhythm due to the anaesthetic treatment used during surgery. The abnormal rhythm was managed and corrected after the procedure with no further complications.

Case Background

• The subject of this case study was a 2-day-old baby horse who presented to a veterinary hospital with digestive issues including constipation and abdominal pain.
• Other symptoms included fast heart rate (tachycardia), rapid breathing (tachypnea), and low oxygen in the blood (hypoxemia).
• An analysis revealed the foal had an accumulation of meconium, the early stool passed by a newborn. This condition necessitated surgical intervention.

Anesthesia and Complications

• The medical team administered several drugs to induce sedation and anaesthesia prior to the abdominal surgery.
• During intubation, the foal showed some reflexive responses, indicating mild sedative effects.
• As a result, the anesthetic isoflurane was administered along with oxygen, which resulted in an irregular heart rhythm called Accelerated Idioventricular Rhythm (AIVR) on the foal’s electrocardiogram.

Management of Accelerated Idioventricular Rhythm

• This specific heart rhythm disorder is characterized by atrioventricular isorhythmic dissociation with wide and uniform QRS complexes, which was exhibited by the foal.
• The arrhythmia persisted throughout the operation despite the administration of Lidocaine, an antiarrhythmic drug.
• However, once isoflurane was discontinued at the end of the procedure, the arrhythmia spontaneously resolved itself, indicating a likely correlation between isoflurane administration and the onset of AIVR.

Postoperative Outcome

• The foal recovered from anesthesia without any complications, and no further cardiac abnormalities were observed before the foal was discharged from the hospital.
• The study concludes that the administration of isoflurane, especially under hypoxic conditions, may pose a risk of inducing AIVR. Accordingly, appropriate management and monitoring of such rhythm anomalies are vital to mitigate adverse effects and ensure recovery.