CARDIOTHORACIC RATIO AND VERTEBRAL HEART SCALE IN CLINICALLY NORMAL BLACK-RUMPED AGOUTIS (DASYPROCTA PRYMNOLOPHA, WAGLER 1831)

Abstract

Wild rodents, such as the lowland paca (Cuniculus paca), capybara (Hydrochoerus hydrochaeris), rock cavy (Kerodon rupestris), guinea pig (Cavia aperea), and black-rumped agouti (Dasyprocta prymnolopha) are intensely hunted throughout Amazonia and at the semiarid regions of northeastern Brazil. To contribute to the preservation of these species, more information about their anatomy, physiology and pathophysiology is needed. The aim of this study was to standardize the vertebral heart scale (VHS) and cardiothoracic ratio (CTR) in clinically normal black-rumped agouti, as well as to compare the results of these two methods, which are commonly used to evaluate the cardiac silhouette in domestic animals. Twelve healthy black-rumped agoutis, divided into two groups (six males and six females), obtained from the Nucleus for Wild Animal Studies and Conservation at the Federal University of Piauí, were radiographed in right and left lateral and dorsoventral projections. The values of the VHS were 8.00±0.31v (the number of thoracic vertebral length spanned by each dimension, starting at T4) for males and 8.11±0.41v for females, and there was no statistical difference between the decubitus (right and left) or between males and females (P>0.05). The CTR mean values obtained were 0.51±0.03 for males, and 0.52±0.02 for females, and there was no statistical difference between the genders (P>0.05). However, there was positive correlation between VHS and CTR (r=0.77 right decubitus and r=0.82 left decubitus). The thoracic and heart diameter had mean values of 6.72±0.61 and 3.48±0.30 cm (males), and for the females, it was 6.61±0.51 and 3.5±0.30 cm, respectively, and there was statistical difference between the genders. The results demonstrated high correlation between the VHS and CTR producing similar results, indicating similar clinical precision for assessing the size of the cardiac silhouette in the black-rumped agoutis.

Vertebral heart size in chinchillas (Chinchilla lanigera) using radiography and CT

“… 2007 , de Moura et al . 2015 ). Interestingly, the VHS was significantly larger for beagles (Kraetschmer et al .…”

“…The vertebral heart size (VHS) measurement system was created as a means to objectively measure cardiac silhouette size in dogs and its development has been described in other companion animal species, including cats, ferrets and rabbits (Buchanan & Bucheler 1995 , Stepien et al 1999 , Litster & Buchanan 2000 , Onuma et al 2010 , Giannico et al 2015 ). There is little information regarding VHS in rodents (Diniz et al 2013 , de Moura et al 2015 , Garcia et al 2016 ), but VHS reference intervals have not been described in chinchillas. Although the heart is often included in radiographic and CT imaging in chinchillas, objective interpretation of cardiac size can be facilitated using VHS.…”

Assessment of the vertebral heart scale and cardiothoracic ratio to standardize the heart size of collared peccaries (Tayassu tajacu Linnaeus, 1758) restrained with ketamine and midazolam

“…In the collared peccary, no significant statistical difference was observed between males and females for the CTR, a characteristic also observed in tonkeana and cylopis monkeys by Schillaci et al (2009), and capuchin monkeys (Cebus apella) by Rocha-Neto et al (2015) and in agoutis (Dasyprocta prymnolopha) by Moura et al (2015). These results are probably due to behavioral characteristics in captivity, both for males and females; there were no marked differences in the cardio-hemodynamic profile in this wild species, and thus there was close conformation of the cardiac silhouette between the genders.…”

“…In humans, a cardiothoracic ratio of >0.5 on a postero-anterior radiograph showed a good predictor of left ventricular dysfunction (Chana et al 2015). Studies have aimed to standardize CTR values in nonhuman primates (Schillaci et al 2009) and wild rodents (Moura et al 2015), but are still scarce in several wild species, with no reports for species proposed in this research.…”

Morphology of the Cervical Lymph Nodes of Agouti (Dasyprocta prymnolopha, Wagler, 1831)

“…After certifying that the anesthetic plan was appropriate, the agoutis were euthanized with an overdose of sodium thiopental intravenously until death due to cardiorespiratory arrest was observed. 6 Finally, the dead agoutis were stored in formaldehyde, to preserve them for later collection of tissue. For the collection work, first the agouti was removed from the formaldehyde and bathed for 24 hours in running water.…”