Changes in Heart Rate Variability with Induction of Gastric Ulcers in Adult Horses.

Gastric ulceration can be induced by athletic training and is a significant welfare concern. The objective of this study was to evaluate the effect of gastric ulcer induction on heart rate variability (HRV) in the horse. We hypothesized that induction of gastric ulcers would decrease HRV and increase low frequency fluctuations, consistent with increased sympathetic tone. A convenience sample of 8 horses in a larger study were enrolled. Horses were randomly assigned to receive water or 2 mg/kg omeprazole orally once daily for 28 days. Gastric ulcers were induced through intermittent feed withholding on days 21 to 28. Gastroscopy was performed and gastric ulcers were graded (0-IV) by three blinded reviewers on days 21 and 28. Continuous electrocardiograms were obtained for one hour at the start and end of ulcer induction. HRV was assessed in 1-hour recordings for time domain variables and 5 minute sections for frequency domain analysis. HRV and ulcer grade across treatments were compared by a mixed effect model, with treatment and time as fixed effects and horse as a random effect. Gastric ulcer grade increased with induction protocol (P < .0001) and decreased with omeprazole treatment (P = .0007). Omeprazole treatment increased R-R intervals (P = .01) and decreased ratio of low frequency/high frequency signal (P = .008) as compared to horses receiving water. This was attributable to decreasing low frequency fluctuations (P = .05). While limited by the small sample size (four horses/treatment), this study suggests that omeprazole treatment decreases heart rate, and LF/HF ratio during ulcer induction, consistent with a decrease in sympathetic tone.

Closure of a patent ductus arteriosus in a 2-week-old llama cria using an Amplatz canine duct occluder.

A two-week-old female llama cria was brought to the UC Davis Large Animal Hospital for evaluation of a cardiac murmur and suspected syncopal episodes. A grade IV/VI left basilar continuous murmur was present on cardiac auscultation. Echocardiography revealed a left-to-right shunting patent ductus arteriosus (PDA), mild left ventricular enlargement, scant pericardial effusion, and a suspected persistent left cranial vena cava. The PDA was successfully closed with an Amplatz canine duct occluder. Mild mitral regurgitation was present on echocardiography performed 7 d following PDA occlusion. No syncopal episodes were observed in hospital prior to or following PDA occlusion. At approximately 1 mo following PDA closure, a grade I/VI left apical systolic murmur was present and the cria's body condition was improved. Key clinical message: Patent ductus arteriosus closure is achievable in New World camelids using interventional cardiology which provides a minimally invasive treatment option for valuable or companion animals. Since interventional cardiac catheterization is commonly performed in small animal species, veterinary cardiologists are well-equipped to apply these skills to camelids.

Fermeture d'un canal artériel persistant chez un lama cria âgé de 2 semaines à l'aide d'un obturateur de conduit canin Amplatz. Une femelle lama cria âgée de deux semaines a été amenée à l'UC Davis Large Animal Hospital pour l'évaluation d'un souffle cardiaque et d'épisodes syncopaux suspectés. Un souffle continu basilaire gauche de grade IV/VI était présent à l'auscultation cardiaque. L'échocardiographie a révélé une persistance du canal artériel avec perméabilité de gauche à droite (PDA), une légère hypertrophie ventriculaire gauche, un léger épanchement péricardique et une suspicion de veine cave crâniale gauche persistante. Le PDA a été fermé avec succès avec un obturateur de conduit canin Amplatz. Une régurgitation mitrale légère était présente sur l'échocardiographie réalisée 7 jours après l'occlusion du PDA. Aucun épisode de syncope n'a été observé à l'hôpital avant ou après l'occlusion du PDA. Environ 1 mois après la fermeture du PDA, un souffle systolique apical gauche de grade I/VI était présent et l'état corporel du cria s'était amélioré.Message clinique clé :La fermeture brevetée du canal artériel est réalisable chez les camélidés du Nouveau Monde en utilisant la cardiologie interventionnelle qui offre une option de traitement peu invasive pour les animaux de valeur ou de compagnie. Étant donné que le cathétérisme cardiaque interventionnel est couramment pratiqué chez les petites espèces animales, les cardiologues vétérinaires sont bien équipés pour appliquer ces compétences aux camélidés.(Traduit par Dr Serge Messier).

Complex central nervous system malformations in a Dutch Warmblood foal.

A neonatal Dutch Warmblood colt was evaluated for inability to stand, incoordination and intention tremor. Despite partial improvement in clinical signs during the first 4 days of hospitalization, neurological deficits remained. Magnetic resonance imaging identified a unilateral infratentorial arachnoid cyst-like lesion with ipsilateral compression and displacement of the cerebellar hemisphere, absent corpus collosum, polymicrogyria, suspect leukoencephalopathy, and noncompressive occipitoatlantal malformation. Improvement in clinical signs during the first 6 months of life suggests that horses can survive with complex congenital neurological malformations, but prognosis for athletic performance is poor. The accessibility of magnetic resonance imaging should improve the diagnostic accuracy of central nervous system disorders in neonatal foals in which congenital malformations are suspected. Euthanasia often is elected in foals with suspected congenital central nervous system disorders because of poor prognosis for athletic performance, limiting understanding of clinical progression in these cases.