Electrocardiography in horses, part 2: how to read the equine ECG

The equine practitioner is faced with a wide variety of dysrhythmias, of which some are physiological. The recording of an exercise electrocardiogram (ECG) can help distinguish between physiological and pathological dysrhythmias, underlining the importance of exercise recordings. The evaluation of an ECG recording should be performed in a highly methodical manner in order to avoid errors. Each P wave should be followed by a QRS complex, and each QRS complex should be preceded by a P wave. The classification of dysrhythmias according to their origin helps to understand the associated changes on the ECG. In this respect, sinoatrial nodal (SA nodal), atrial myocardial, atrioventricular nodal (AV nodal) and ventricular myocardial dysrhythmias can be distinguished. Artefacts on the ECG can lead to misinterpretations. Recording an ECG of good quality is a prerequisite to prevent misinterpretations, but artefacts are almost impossible to avoid when recording during exercise. Changes in P or T waves during exercise also often lead to misinterpretations, however they have no clinical significance

Electrocardiography in horses, part 1: how to make a good recording

Upon auscultation, cardiac dysrhythmias can be suspected, but electrocardiography is the ultimate diagnostic tool. Electrocardiogram (ECG) recording used to be reserved to specialized centers, but nowadays relatively cheap and small recorders are available to the practitioner in the field. ECGs can therefore be recorded ambulatory and during prolonged periods at rest or even during exercise. The know-how of a good quality recording is mandatory for a correct diagnosis. The basic equipment consists of electrodes, a recorder and a way to display the trace. Self-adhesive electrodes should be used, and positioned along the mean electrical axis of the heart. Small recording devices offer the advantage of allowing recordings during exercise. As the electrical impulse spreads through the heart, the ECG trace shows successively a P wave, a QRS complex and a T wave. T-a waves are not always clearly visible in horses. The positioning of the electrodes may differ for ambulatory, exercise or long-term resting recordings. However, as long as the electrodes are positioned along the mean electrical axis, their exact position is not of crucial importance

Accuracy of transcranial magnetic stimulation and a Bayesian latent class model for diagnosis of spinal cord dysfunction in horses

Background: Spinal cord dysfunction/compression and ataxia are common in horses. Presumptive diagnosis is most commonly based on neurological examination and cervical radiography, but the interest into the diagnostic value of transcranial magnetic stimulation (TMS) with recording of magnetic motor evoked potentials has increased. The problem for the evaluation of diagnostic tests for spinal cord dysfunction is the absence of a gold standard in the living animal. Objectives: To compare diagnostic accuracy of TMS, cervical radiography, and neurological examination. Animals: One hundred seventy-four horses admitted at the clinic for neurological examination. Methods: Retrospective comparison of neurological examination, cervical radiography, and different TMS criteria, using Bayesian latent class modeling to account for the absence of a gold standard. Results: The Bayesian estimate of the prevalence (95% CI) of spinal cord dysfunction was 58.1 (48.3%-68.3%). Sensitivity and specificity of neurological examination were 97.6 (91.4%-99.9%) and 74.7 (61.0%-96.3%), for radiography they were 43.0 (32.3%-54.6%) and 77.3 (67.1%-86.1%), respectively. Transcranial magnetic stimulation reached a sensitivity and specificity of 87.5 (68.2%-99.2%) and 97.4 (90.4%-99.9%). For TMS, the highest accuracy was obtained using the minimum latency time for the pelvic limbs (Youden's index = 0.85). In all evaluated models, cervical radiography performed poorest. Clinical Relevance: Transcranial magnetic stimulation-magnetic motor evoked potential (TMS-MMEP) was the best test to diagnose spinal cord disease, the neurological examination was the second best, but the accuracy of cervical radiography was low. Selecting animals based on neurological examination (highest sensitivity) and confirming disease by TMS-MMEP (highest specificity) would currently be the optimal diagnostic strategy

Plasma exchange as a treatment for hyperbilirubinemia in 2 foals with neonatal isoerythrolysis

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Left abomasal displacement between the uterus and rumen during bovine twin pregnancy

Here, we describe two cases of left displaced abomasum (LDA) in Holstein cattle at 6 and 9 months of twin gestation. Clinical examination revealed signs of proximal ileus with marked abdominal distension, but no ping sounds. An unusually high position of the gravid uterine horn on the left side was observed with ultrasound. Left exploratory laparotomy confirmed that the abomasum was displaced to the left and entrapped between the rumen and twin gravid uterine horn. A left surgical approach was necessary to correct the condition. Both animals recovered and gave birth to healthy twins. The present cases indicate that the subomental position of a heavy twin gravid uterine horn is a possible mechanical cause of LDA

Echografische diagnose van complexe congenitale hartafwijkingen bij twee volwassen paarden

Two adult horses were presented with a cardiac murmur. Both animals were hypoxemic without signs of dyspnea. A complex congenital cardiac anomaly was detected by means of echocardiography in both animals. It concerned a double outlet right ventricle in a 3-year-old mare and a pentalogy of Fallot in an 8-year-old mare

Atypische myopathie bij het paard

Atypical myopathy (AM) is a frequently fatal pasture myopathy that emerges in Europe. Outbreaks are of an acute and unexpected nature and practitioners and owners should be prepared to handle the critically ill patients of this disease. Different hypotheses concerning the etiology and pathogenesis have been described. In this review, the most important hypotheses are summarized, and treatment plans and preventive measures are suggested. At this moment, maple seeds are thought to be the cause of AM. These seeds contain a toxin, hypoglycin A, which may lead to multiple acyl-CoA dehydrogenase deficiency (MADD). Treatment is often limited to supportive care. Since treatment is often unsuccessful, the main emphasis is currently still on prevention