Third‐Degree Atrioventricular Block and Collapse Associated with Eosinophilic Myocarditis in a Horse

Luethy, Daniela; Slack, JoAnn; Kraus, Marc S.; Gelzer, Anna R.; Habecker, Perry L.; Johnson, Amy L.

doi:10.1111/jvim.14682

Cited by 8 publications

(8 citation statements)

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“…If treatment of NMD would have been successful in this foal, the complete AV block would have been needed to be addressed. Reported causes of complete AV block include myocardial inflammation or degeneration (van Loon et al 2001;Luethy et al 2017;Ertelt et al 2018), neoplastic infiltration (Sugiyama et al 2008), congenital anomalies (Pibarot et al 1993) and toxic agents (Lawler et al 2008). In this foal, myocardial inflammation and necrosis interrupted impulse conduction.…”

Section: Discussionmentioning

confidence: 97%

“…Complete atrioventricular (AV) or third-degree AV block is a rare condition in horses and is often associated with myocardial inflammation or degeneration (van Loon et al 2001;Lawler et al 2008;Luethy et al 2017). In a case report of a donkey with complete AV block, a congenital disorder was suspected (Pibarot et al 1993) and anecdotal reports of third-degree AV block caused by a lymphoma or snake envenomation are described (Sugiyama et al 2008;Lawler et al 2008).…”

Section: Introductionmentioning

confidence: 99%

“…2008; Luethy et al . 2017). In a case report of a donkey with complete AV block, a congenital disorder was suspected (Pibarot et al .…”

Section: Introductionmentioning

confidence: 99%

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Complete AV block in a neonatal foal suffering from nutritional myodegeneration

Conze

Falkenau

Goehring

et al. 2021

Equine Veterinary Education

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This case report concerns a 1-day-old, full-term Quarter Horse colt presented due to a progressive inability to rise and nurse. Besides the general weakness, a marked bradycardia was evident, which was caused by a third-degree atrioventricular (AV) block. Subsequently, the diagnosis of acute nutritional myodegeneration (NMD) was made based on clinical signs, elevated muscle enzymes, ECG findings, as well as low serum selenium and vitamin E values. Despite intensive care and supportive therapy, the foal´s condition deteriorated, and euthanasia was elected. Necropsy confirmed the diagnosis of NMD and revealed diffuse necrosis and inflammatory infiltration of the skeletal and myocardial musculature, as well as the cardiac conduction system which might have resulted in complete AV block.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Complete AV block in a neonatal foal suffering from nutritional myodegeneration

Conze

Falkenau

Goehring

et al. 2021

Equine Veterinary Education

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“…Rare but debilitating, these conditions are a research priority in human medicine (Bochner et al ; Khoury et al ; O'Sullivan and Bochner ). Horses suffer from EADs, including those that affect isolated body systems (Dixon et al ; Lankveld ; Uhlhorn et al ; Climent et al ; Loibl et al ; Archer et al ; Lassaline‐Utter et al ; Luethy et al ; Trimble et al ), as well as multisystemic eosinophilic epitheliotropic disease (MEED), which affects multiple body systems simultaneously (Bosseler et al ). Lesions can occur in the gastrointestinal tract, skin, liver, pancreas, lymph nodes, kidney, bile ducts and respiratory tract (Bosseler et al ; Pucheu‐Haston and Del Piero ).…”

Section: Allergic Skin Diseasementioning

confidence: 99%

Eosinophils of the horse: Part II: Eosinophils in clinical diseases

Brosnahan

2020

Equine Veterinary Education

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Interpretation of eosinophilia in body fluids or tissues is often not straightforward. Eosinophil counts vary among clinically healthy individuals, and considerable overlap can occur between normal and affected animals in conditions such as allergic airway disease. Parasite exposure is a confounding factor when counts are increased, and in cases where very high counts and dramatic clinical signs make another disease process obvious, the underlying pathology may be uncertain and treatment difficult. Eosinophils are a component of the immune response in many diseases of the horse, but their specific role is often unknown and likely multifactorial. In helminth infections, eosinophils are assumed to be part of the normal host response to a pathogen, whereas in multisystemic eosinophilic epitheliotropic disease (MEED), the predominance of eosinophils likely represents a wildly dysregulated response, or an abnormal response altogether. This distinction is still not clear for other diseases. Understanding the pathways involved in recruitment, activation or suppression of eosinophils is required for more accurate diagnostics, effective therapeutics, and successful strategies for prevention of eosinophil associated diseases. Eosinophils of the horse: Part II reviews published observations on the eosinophil in clinical diseases of the horse. The behaviour of eosinophils in three common and relatively wellstudied conditions is presented first, including gastrointestinal helminth infections, non-infectious respiratory disease, and insect bite hypersensitivity. The less common eosinophilassociated diseases such as eosinophilic disease confined to the intestine (EDCI) and MEED are considered, followed by a brief summary of the eosinophil in phycomycosis and neoplasia. In conclusion, a panoramic view of the equine eosinophil as presented in Parts I and II is placed in the larger context of current eosinophil research, and areas of study are identified that may improve our understanding of eosinophil biology in equine health and clinical disease. Gastrointestinal parasites of the horse Gastrointestinal helminths are a widespread and well-studied problem in the horse. Clinical disease is associated historically with migratory large strongyles (Strongylus vulgaris, S. edentatus, S. equinus), small strongyles (cyathostomes), tapeworms (Anoplocephala perfoliata) and, in foals, ascarids (Parascarus equorum). Early studies sought to define parasite life cycles, but post-infection necropsies also described the eosinophilic response (Duncan and Pirie 1975). Host immunity and anthelmintics were the focus of later works (Bailey et al. 1989; Steuer et al. 2018). Variables exist across studies, including dosing variations, natural versus experimental

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“…Most often, the arrhythmia does not inflict any clinical impact on the horses and is deemed harmless if the second-degree AV blocks disappear when vagal activity is withdrawn, such as under light exercise [ 3 ]. Most clinical cases covering the AV nodal function report third-degree AV block as a result of severe systemic disease or local damage of the AV node [ 4 , 5 , 6 , 7 ], but little is known about the etiology of second-degree AV blocks. Only a few studies of pronounced second-degree AV blocks have reported associations to inflammation or degenerative changes of the AV node [ 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Cartilaginous Intrusion of the Atrioventricular Node in a Quarter Horse with a High Burden of Second-Degree AV Block and Collapse: A Case Report

Nissen

Saljic

Kjeldsen

et al. 2022

Animals

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Second-degree atrioventricular (AV) block is the most common cardiac arrhythmia in horses, affecting 40–90% depending on breed. Usually, the AV blocks occur while the horses are resting and disappear upon exercise and are, therefore, considered to be uneventful for horses. However, if the AV blocks occur frequently, this may result in syncope and collapse. Identifying the cause of second-degree AV block is difficult and often subscribed to high vagal tone. In this report, we present an eight-year-old Quarter horse with a high burden of second-degree AV blocks and multiple collapses. The clinical examination, including neurological examination, blood analysis, 24-h ECG recording and cardiac echocardiography, did not reveal any signs of general or cardiovascular disease besides a high burden of second-degree AV blocks (~300 blocks per hour) and a hyperechoic area in the AV nodal region. An implantable loop recorder (ILR) was inserted to monitor the cardiac rhythm. The ILR detected several consecutive second-degree AV blocks and pauses above 5 s. However, unfortunately, no recordings were available during the collapses. Eventually, the horse was euthanized and the heart inspected. The aortic root was severely cartilaginous and appeared to penetrate the AV node, especially in the His bundle region, possibly explaining the hampered AV conduction. Nevertheless, it is still uncertain if the AV nodal disruption caused the collapses and more knowledge on AV nodal diseases in horses is warranted.

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Third‐Degree Atrioventricular Block and Collapse Associated with Eosinophilic Myocarditis in a Horse

Cited by 8 publications

References 35 publications

Complete AV block in a neonatal foal suffering from nutritional myodegeneration

Complete AV block in a neonatal foal suffering from nutritional myodegeneration

Eosinophils of the horse: Part II: Eosinophils in clinical diseases

Cartilaginous Intrusion of the Atrioventricular Node in a Quarter Horse with a High Burden of Second-Degree AV Block and Collapse: A Case Report

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