Accelerated Idioventricular Rhythm Associated With Isoflurane Administration in a Foal: A Case Report.
Authors: Peña-Cadahia Celia, Manso-Díaz Gabriel, Santiago-Llorente Isabel, Villalba-Orero María
Journal: Journal of equine veterinary science
Summary
# Editorial Summary A 2-day-old filly with meconium impaction and concurrent hypoxaemia developed accelerated idioventricular rhythm during isoflurane anaesthesia, which resolved immediately upon discontinuation of the volatile agent. The case details a clinical scenario involving inadequate initial sedation (diazepam and butorphanol) requiring rescue sedation with xylazine, followed by ketamine induction and isoflurane maintenance via face mask prior to intubation. Electrocardiographic monitoring revealed characteristic atrioventricular isorhythmic dissociation with wide monomorphic QRS complexes; lidocaine administration failed to suppress the arrhythmia, which spontaneously corrected once isoflurane was withdrawn. The authors highlight that isoflurane's known sensitisation of the myocardium to catecholamines, combined with pre-existing hypoxaemia in this foal, created conditions conducive to ectopic ventricular automaticity. For equine practitioners managing neonatal cases requiring anaesthesia, this report underscores the importance of pre-operative oxygenation and vigilant electrocardiographic monitoring, particularly when volatile agents are employed in compromised patients, and reinforces that increasing supportive care (oxygen supplementation) rather than escalating pharmacological intervention may be the appropriate response to isoflurane-associated arrhythmias.
Read the full abstract on PubMed
Practical Takeaways
- •Isoflurane carries arrhythmia risk in foals with pre-existing hypoxemia; optimize oxygenation and consider alternative anesthetics in compromised neonates
- •Accelerated idioventricular rhythm in anesthetized foals may not require treatment with lidocaine and often resolves when the triggering agent is discontinued
- •Monitor cardiac rhythm closely during induction and maintenance in young foals, particularly those presenting with respiratory compromise or metabolic derangement
Key Findings
- •A 2-day-old foal developed accelerated idioventricular rhythm with atrioventricular isorhythmic dissociation during isoflurane anesthesia
- •The arrhythmia persisted despite lidocaine administration but spontaneously resolved upon discontinuation of isoflurane
- •Pre-existing hypoxemia likely exacerbated the arrhythmogenic effects of isoflurane in this case
- •The foal recovered without complications and experienced no further cardiac events postoperatively