Comparative Study of the Vertebral Heart Scale (VHS) and the Cardiothoracic Ratio (CTR) in Healthy Poodle Breed dogs

Abstract

Background: Veterinary cardiology has been widely divulged, especially because of the search for diagnostic methods that allow early identification of heart disease in companion animals. Several techniques are available, such as digital radiography (DR), computerized tomography (CT) and magnetic resonance (MR) that are being applied to patients with various diseases. VHS has been widely used in clinical practice in veterinary medicine as a way to diagnose heart size increases in lateral thoracic radiography in small animals. Cardiothoracic ratio (CTR) is a predictive factor for cardiac insufficiency in humans. In veterinary medicine, this index is still little used. The objective of the present study was to compare the vertebral heart scale (VHS) and cardiothoracic ratio (CTR) to assess changes in the size of the cardiac silhouette dogs in thoracic radiographs.Materials, Methods & Results: The VHS and CTR of forty healthy poodle breed dogs (20 males and 20 females) from University Veterinary Hospital at the Federal University of Piauí were assessed. The animals were placed in supine and lateral decubitus, to obtain radiographic images in dorsoventral (DV) and right and left laterolateral projections of the thoracic region. The images acquired on the photosensitive radiographic chassis were analyzed by digital radiographic image system installed in the Image Diagnosis Service of the University Veterinary Hospital -HVU/UFPI. VHS (Vertebral Heart Scale) measurements were taken using the sum of the heart length and heart width at its greatest diameter, comparing with the vertebral bodies from the fourth thoracic vertebra (T4). The CTR was assessed by comparing the greatest width of the heart silhouette and the distance between the thoracic walls at height T8. The heart width was measured from the two greatest distances (ML and MR), from the vertical line that divides the limit between the right and left sides of the heart, at the point of its greatest diameter. Similarly, the thoracic width was measured at the point of greatest thoracic diameter (MTD). The mean of the VHS and CTR in the males was 9.83 ± 0.85v and 0.48 ± 0.05, respectively. The females showed values of 9.65 ± 0.65v and 0.50 ± 0.03, respectively (P > 0.05). The mean of the VHS and CTR, considering males and females, was 9.72 ± 0.73v and 0.48 ± 0.04, respectively. VHS and weight correlated positively (r = 0.96), as the CTR and weight (r = 0.94). VHS and age showed high correlation (r = 0.96) as CTR and age (r = 0.93). VHS and CTR showed high correlation (r = 0.96).Discussion: Although congenital malformations and genetic diseases can occur, the acquired heart diseases correspond to most of the complications found in dogs. VHS increases considerably 6 to 12 months before the development of congestive heart failure (CHF). The poodles studied, considering the universe of males and females (P < 0.05), presented mean VHS values of 9.72 ± 0.73v. Similarly, there was no significant difference between genders for VHS measured in right and left decubitus in normal dogs. The cardiothoracic ratio measured for the poodles studied showed mean values of 0.48 ± 0.05. In humans, values below 0.5 are considered normal, while values above this may indicate the presence of cardiomegaly. The CTR is intimately related to the volume of the left ventricle and CTR values above 0.5 in humans are pathological. Our results demonstrated that VHS and CTR showed strong correlation in their measurements, suggesting that CTR, constantly used in humans, could be considered as a tool to assess the size of the heart silhouette in dogs of the poodle breed.

Radiographic anatomy of the heart of fruit bats

“…Based on lateral radiographs, it can be analysed the heart size of the three bat species taking into account the VHS and ICS values. VHS values are the sum of the long axis (L) and short axis (S), which are projected on the 4th thoracic vertebrae (Azevedo et al., 2016), as shown in Figure 5. All three types of bats are known to have VHS and ICS values as contained in Table 1.…”

Estimation of vertebral heart size and cardiothoracic ratio in Persian cats

“…In the assessment of CTR and the increase in cardiac size, the use of VD images has been recommended rather than DV radiograph and it has been reported that animals have a normal heart silhouette only in the supine position (Van Den Broek & Darke, 1987). In the CTR studies conducted with monkeys and dogs, references values have been provided for these animal species and it has been reported that this ratio has not had statistical differences between sexes (Rocha‐Neto et al., 2015; Azevedo et al., 2016). In the present study, we determined the cardiothoracic ratio through both DV and VD images in the Persian cats.…”

“…The measurements obtained from the radiograph were performed in accordance with the methods reported by Azevedo et al. (2016), Litster and Buchanan (2000a), Schillaci et al. (2009) and Ukaha (2013).…”

“…Another method in determining cardiomegaly is the cardiothoracic ratio (CTR). DV and VD in animals are obtained by dividing the short‐axis value which has the widest heart silhouette in chest radiograph to the widest distance of the thoracic wall (at the 8th thoracic vertebral level) (Schillaci et al., 2009; Azevedo et al., 2016).…”

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

“…Studies of heart measurements in domestic animals have been conducted for species such as dogs (Lamb et al 2001), cats (Litster & Buchanan 2000), horses (Patteson et al 1995), goats (Ukaha et al 2013) and pigs. However, variables such as breed, animal size and thoracic shape have influenced the standardization of the mean vertebral scale of the normal heart, as has been observed in the domestic species already assessed (Azevedo et al 2016). Buchanan & Bücheler (1995) determined that values for dogs obtained in lateral projections were smaller or equal to 10.5 vertebra (v) in 98% of the radiography of clinically normal dogs.…”