Eletrocardiografia basal e após exercício em cães braquicefálicos / Baseline and post exercise electrocardiography in brachycephalic dogs

Background: The brachycephalic dog breeds have been increasing in Brazil, and these animals are predisposed to present the brachycephalic dog syndrome, consisting of anatomical defects that lead to physiological changes and clinical signs such as wheezing, dyspnea, and hypoxia. Electrocardiography (ECG) is a simple test that can detect disturbances in the electrical activity of the heart, including changes present in hypoxia. The brachycephalic dog syndrome can lead to pulmonary hypertension due to hypoxia. Based on this, the present work aimed to evaluate the ECG of brachycephalic dogs in search of significant changes in heart rhythm, ECG waves, and cardiac axis. Materials, Methods & Results: Twenty-nine dogs were evaluated in this study, 19 brachycephalic and 10 mesaticephalic, after approval by an ethics committee the animals were selected. Electrocardiographic examinations were performed in 2 stages, at rest and immediately after a 3-min trot. The exam was performed with a computerized electrocardiograph, with a standard time of 5 min. The standard positioning for performing the examination was the right lateral decubitus position. To improve the electrical conductivity, 70% alcohol was used between the animal's skin and the electrodes. In statistical analysis, paired t test was performed for comparison of the same group before and after exercise and unpaired t test between groups at the same moments, considering P < 0.05 as significant. Nineteen brachycephalic animals were evaluated, 10 Pugs and 9 French Bulldogs, 9 males and 10 females. The mean age was 3.4 ± 1.8 years; and the mean weight was 12.5 kg ± 2.7 kg. In the control group, consisting of ten mesaticephalic animals, all were non-breed, three males and seven females; the mean age and weight in this group were 4.4 ± 1.5 years and 7.5 kg ± 0.5 kg, respectively. There was a significant increase in heart rate (bpm) after exercise in brachycephalic dogs (baseline: 119.3 ± 4.3; after exercise: 135.1 ± 4.9; P = 0.0005). The same occurred for P wave amplitude (mV) (baseline: 0.20 ± 0.01; after exercise: 0.22 ± 0.01; P = 0.0001). These differences were not found in the control group. There were no alterations in the duration of the P wave, PR interval, QRS complex, and QT interval, and all were within normal values for the species in both groups. The R-wave amplitude remained unaltered and within normal values in both the control and brachycephalic groups. Discussion: The elevation in heart rate may be associated with the chemoreflex secondary to the increased demand for oxygenation during exercise and the hypoxia generated by it. The increase in P amplitude suggests right atrial overload. The P wave corresponds to the atrial depolarization and its amplitude corresponds to the electrical activity in the right atrium. Thus, it is possible to relate the increase in P amplitude and heart rate to the hypoxia caused by exercise in brachycephalic, since this hypoxia results in chemoreceptor activation that increases chronotropism and heart rate. Also, there may be increased pressure in the pulmonary trunk, this increased pressure occurs due to vasoconstriction generated as a reflex to hypoxia in the pulmonary alveoli, leading to a possible picture of acute pulmonary hypertension that, in a cascade effect, leads to hypertrophy and dilation of the right ventricle, increased strength of contractility and ejection affecting the tricuspid valve causing a reflux and consequent overload of the right atrium.

Brachycephalic syndrome in dogs - endoscopic findings in the airways

Background: Brachycephalic dogs have several abnormalities in the airways, which generate clinical manifestations that impair the quality of life of these animals. Primary alterations promote airflow obstruction and increase intraluminal negative pressure, causing secondary alterations due to a cycle of inflammation with consequent obstruction. With the onset of inflammation and other alterations in the airways, clinical manifestations can be observed, such as snoring, reverse sneezing, coughing, dyspnea, cyanosis, syncope, and vomiting. Endoscopic examination of the airways allows visualization and diagnosis of morphological changes in these animals. This study aimed to evaluate the endoscopic findings of the airways and determine the quantitative and qualitative assessment of the severity of clinical manifestations in 14 dogs with brachycephalic syndrome (BS). Materials, Methods & Results: Historical and anamnesis data and clinical, respiratory, and digestive manifestations were collected from the owners' reports. The clinical manifestations were classified as mild, moderate, or severe. All animals were subjected to endoscopy of the airways, and image findings were grouped according to the anatomical site where they were observed, then the abnormalities were correlated with the severity of the clinical manifestations. When comparing the frequency of endoscopic abnormalities with the severity of clinical manifestations, it is interesting to observe that animals with severe disease more frequently presented the following alterations: prolongation and thickening of the soft palate, laryngeal changes, presence of hyperemia, lymphoid hyperplasia and polyps in the nasopharynx, hypoplasia and presence of tracheal secretion and thickening of the dorsal tracheal muscle; bronchial collapse, hypoplasia of the main bronchi and bronchial hyperemia and the presence of aberrant nasal turbinates. Comparison between the means of nonparametric variables was performed using the Mann-Whitney test, with a 5% significance level. Discussion: A higher frequency of French Bulldog dogs included in the study was observed, probably due to their greater popularity, although any brachycephalic dog may be affected by BS. Considering that nostril stenosis is a congenital alteration, which is usually diagnosed early, and since the animals included in the study were dogs referred for the rhinoplasty procedure the higher frequency of young dogs in the study was not surprising. The results revealed a significant difference in the endoscopic findings with the severity of the clinical manifestations in different variables, such as prolongation and thickening of the soft palate, eversion of the laryngeal saccules, presence of laryngeal inflammation and collapse, presence of polyps or lymphoid hyperplasia in the nasopharynx, thickening of the dorsal muscle of the trachea, polyps in the trachea and hypoplasia in addition to bronchial hyperemia. The larynx was the most affected anatomical site, with alterations present in 92.8% of the evaluated dogs. Based on these findings, it can be concluded that airway obstruction caused by primary alterations can cause secondary alterations, with consequent clinical manifestations in brachycephalic dogs it is possible to suggest that dogs with this syndrome may present severe manifestations of the disease, regardless of age. Furthermore, it can be concluded that in this study, dogs with BS had frequent laryngeal alterations and that alterations in the main bronchi were present in all animals with severe manifestations of the disease.

Condutas de médicos veterinários e tutores de cães braquicefálicos frente ao problema / Conducts of veterinary doctors and tutors of brachycephalic dogs in front of the problem

O presente estudo teve como objetivo avaliar a conduta de médicos veterinários e a compreensão de tutores de cães braquicefálicos frente à síndrome braquicefálica (SB). O estudo foi realizado no Brasil e incluiu as causas da SB, os componentes, as consequências e as opções terapêuticas. Foram aplicados dois questionários em plataforma on line, em formato de múltipla escolha. O primeiro foi aplicado a médicos veterinários atuantes nas áreas relacionadas a pequenos animais. O segundo foi aplicado a tutores de cães braquicefálicos, como Pug, Buldogues Francês e Inglês, Shih-tzu, Lhasa Apso, entre outros. Tais cães foram divididos entre raças braquicefálicas extremas e moderadas. A procura por informações sobre a SB, por parte dos tutores, foi considerada baixa, mesmo com a presença de sinais clínicos referentes à SB. Foi notado que os tutores consideram os sinais clínicos como sendo normais para essas raças, apresentando dificuldade para diferenciar os sinais. Notou-se pouca participação de médicos veterinários quanto à explicação e disseminação de informações relacionadas à síndrome e suas consequências. Demonstraram desconhecimento do diagnóstico e possíveis correções. Desta forma, observou-se a necessidade de maior conscientização quanto à SB, tanto entre tutores quanto entre médicos veterinários. Os médicos veterinários demonstraram desconhecer opções terapêuticas para proporcionar qualidade de vida para esses pacientes. A indicação cirúrgica foi baixa, demonstrando a necessidade de maior intervenção por parte dos profissionais.

The present study aimed to assess the conduct of veterinarians and owners of brachycephalic dogs in Brazil regarding the brachycephalic syndrome (BS), its causes, components, consequences and therapeutic options. Two questionnaires were applied using an online platform in a multiple-choice format, in which the first was applied to veterinarians working in the sub-areas related to small animals and the second to owners of brachycephalic dogs, like Pug, French and English Bulldogs, Shih-tzu, Lhasa Apso, among others. The latter group was divided between owners of extreme and moderate brachycephalic breeds. The search for information about the BS by the owners was considered low, even if their animals had clinical signs of BS, and it seemed difficult for them to differentiate these signs, accepting them as "normal" for the mentioned breeds. The participation by veterinarians regarding the explanation and dissemination of information related to BS and its consequences, as well as its diagnosis and possible corrections, was also considered low, thus exemplifying the need for greater awareness of BS among both owners and veterinarians. Furthermore, the instruction by veterinarians aiming a better quality of life for these patients, as well as the surgical treatment indication for these dogs, is low and indicates the need for greater intervention by these professionals.

Gestational echobiometry in brachycephalic bitches using high-definition ultrasonography / Ecobiometria gestacional em cadelas braquicefálicas utilizando ultrassonografia de alta-definição

The objective of the present study was to obtain echobiometric values for the most important canine maternal-fetal tissues using high-definition ultrasonography (HDUS) trying to update the formulas for predicting gestational age. Twelve healthy bitches of brachycephalic breeds weighing 7-13kg and aged one to four years were included. The fetuses were analyzed every day using conventional and high-definition ultrasonography from the eighth day after artificial insemination until the day of delivery, using the ACUSON S2000/SIEMENS ultrasound equipment and specific software. Embryonic and fetal structures; diameter of the embryonic vesicle; length of the embryo; biparietal diameter, abdominal length and kidney height; length of the femur, humerus, scapula, radius, and tibia; thickening of the stomach wall; adrenal length; and cardiac size were measured. These variables were correlated with gestational and adjusted tested according to regression models. The results obtained (P<0.001) for: lateral diameter of the gestational sac (R2=81.8%); length of the embryo (R2=85.7%); biparietal (R2=99.1%) and abdominal diameter (R2=97.2%); thickness of the gastric wall (R2=86.9%); length of the femur (R2=96.6%), radius (R2=97.5%), humerus (R2=96.5%), scapula (R2=95.8%) and tibia (R2=97.3%); kidney length (R2=95.8%) and height (R2=96.0%); adrenal length (R2=89.6%); heart length (R2=93.0%) and height (R2=91.5%) of the canine fetuses showed significant correlation with gestational days. This allowed monitoring fetal growth and estimation of age with high accuracy in different gestational periods.(AU)

O objetivo do presente estudo foi obter valores ecobiométricos para os tecidos materno-fetais caninos, usando a ultrassonografia de alta definição (HDUS), desenvolvendo fórmulas para prever a idade gestacional das cadelas. Doze cadelas saudáveis de raças braquicefálicas pesando 7-13kg e com idades entre um e quatro anos foram incluídas. Os fetos foram analisados diariamente com ultrassonografia convencional e de alta definição, do oitavo dia após a inseminação artificial até o dia do parto, utilizando o equipamento de ultrassom ACUSON S2000/SIEMENS e software específico. Estruturas embrionárias e fetais; diâmetro da vesícula embrionária; comprimento do embrião; diâmetro biparietal, comprimento abdominal e altura renal; comprimento do fêmur, úmero, escápula, rádio e tíbia; espessamento da parede do estômago; comprimento adrenal; e tamanho cardíaco foram medidos. Essas variáveis foram correlacionadas com o teste gestacional e ajustado de acordo com os modelos de regressão. Os resultados obtidos (P<0,001) para: diâmetro lateral do saco gestacional (R2=81,8%); comprimento do embrião (R2=85,7%); diâmetro biparietal (R2=99,1%) e abdominal (R2=97,2%); espessura da parede gástrica (R2=86,9%); comprimento do fêmur (R2=96,6%), rádio (R2=97,5%), úmero (R2=96,5%), escápula (R2=95,8%) e tíbia (R2=97,3%); comprimento do rim (R2=95,8%) e altura (R2=96,0%); comprimento adrenal (R2=89,6%); o comprimento do coração (R2=93,0%) e a altura (R2=91,5%) dos fetos caninos apresentaram correlação significativa com os dias gestacionais. Isso permitiu monitorar o crescimento fetal e estimar a idade com alta precisão em diferentes períodos gestacionais.(AU)

Gestational echobiometry in brachycephalic bitches using high-definition ultrasonography / Ecobiometria gestacional em cadelas braquicefálicas utilizando ultrassonografia de alta-definição

The objective of the present study was to obtain echobiometric values for the most important canine maternal-fetal tissues using high-definition ultrasonography (HDUS) trying to update the formulas for predicting gestational age. Twelve healthy bitches of brachycephalic breeds weighing 7-13kg and aged one to four years were included. The fetuses were analyzed every day using conventional and high-definition ultrasonography from the eighth day after artificial insemination until the day of delivery, using the ACUSON S2000/SIEMENS ultrasound equipment and specific software. Embryonic and fetal structures; diameter of the embryonic vesicle; length of the embryo; biparietal diameter, abdominal length and kidney height; length of the femur, humerus, scapula, radius, and tibia; thickening of the stomach wall; adrenal length; and cardiac size were measured. These variables were correlated with gestational and adjusted tested according to regression models. The results obtained (P<0.001) for: lateral diameter of the gestational sac (R2=81.8%); length of the embryo (R2=85.7%); biparietal (R2=99.1%) and abdominal diameter (R2=97.2%); thickness of the gastric wall (R2=86.9%); length of the femur (R2=96.6%), radius (R2=97.5%), humerus (R2=96.5%), scapula (R2=95.8%) and tibia (R2=97.3%); kidney length (R2=95.8%) and height (R2=96.0%); adrenal length (R2=89.6%); heart length (R2=93.0%) and height (R2=91.5%) of the canine fetuses showed significant correlation with gestational days. This allowed monitoring fetal growth and estimation of age with high accuracy in different gestational periods.(AU)

O objetivo do presente estudo foi obter valores ecobiométricos para os tecidos materno-fetais caninos, usando a ultrassonografia de alta definição (HDUS), desenvolvendo fórmulas para prever a idade gestacional das cadelas. Doze cadelas saudáveis de raças braquicefálicas pesando 7-13kg e com idades entre um e quatro anos foram incluídas. Os fetos foram analisados diariamente com ultrassonografia convencional e de alta definição, do oitavo dia após a inseminação artificial até o dia do parto, utilizando o equipamento de ultrassom ACUSON S2000/SIEMENS e software específico. Estruturas embrionárias e fetais; diâmetro da vesícula embrionária; comprimento do embrião; diâmetro biparietal, comprimento abdominal e altura renal; comprimento do fêmur, úmero, escápula, rádio e tíbia; espessamento da parede do estômago; comprimento adrenal; e tamanho cardíaco foram medidos. Essas variáveis foram correlacionadas com o teste gestacional e ajustado de acordo com os modelos de regressão. Os resultados obtidos (P<0,001) para: diâmetro lateral do saco gestacional (R2=81,8%); comprimento do embrião (R2=85,7%); diâmetro biparietal (R2=99,1%) e abdominal (R2=97,2%); espessura da parede gástrica (R2=86,9%); comprimento do fêmur (R2=96,6%), rádio (R2=97,5%), úmero (R2=96,5%), escápula (R2=95,8%) e tíbia (R2=97,3%); comprimento do rim (R2=95,8%) e altura (R2=96,0%); comprimento adrenal (R2=89,6%); o comprimento do coração (R2=93,0%) e a altura (R2=91,5%) dos fetos caninos apresentaram correlação significativa com os dias gestacionais. Isso permitiu monitorar o crescimento fetal e estimar a idade com alta precisão em diferentes períodos gestacionais.(AU)

Modelos animais das principais craniostenoses humanas / Animal models of the main human craniostenosis

As craniostenoses representam importante grupo de alterações dismórficas fenotípicas dentro da prática clínica, resultantes do fechamento prematuro das suturas cranianas, originando alterações na orientação do crescimento e desenvolvimento normal do crânio, conforme o comprometimento de uma ou mais suturas. Mais do que comprometimento isoladamente estético, alterações neurofuncionais e cognitivas são comuns, especialmente nos casos das craniostenoses sindrômicas malformativas. Apesar dos fenótipos clínicos serem bastante conhecidos da prática médica, especialmente neu- rológica e pediátrica, atualmente o conhecimento referente aos mecanismos fisiopato- gênicos envolvidos ainda é bastante incipiente. Assim, o conhecimento dos principais modelos experimentais animais e o desenvolvimento de novos modelos dirigidos são fundamentais para a compreensão mais ampla das principais doenças que cursam com tal fenótipo. O objetivo deste artigo é fazer uma breve revisão a respeito dos principais modelos animais descritos para as craniostenoses.

Craniostenosis represents an important group of dysmorphic phenotypic changes in clinical practice, resulting from the premature closure of the cranial sutures, causing changes in the orientation of normal growth and development of the skull, according to the compromise of one or more sutures. More than aesthetic compromise alone, neurofunctional and cognitive changes are common, especially in cases of malformative syndromic craniostenosis. Despite the clinical phenotypes are well known in medical practice, mainly neurological and pediatric, the current knowledge regarding the mechanisms involved in its physiopathogenesis are still incipient. Thus, knowledge of the main experimental animal models and developing new targeted models are critical to a broader understanding of major diseases with this phenotype. The objective of this review is to briefly review the main animal models described for craniostenosis.

Modelos animais das principais craniostenoses humanas / Animal models of the main human craniostenosis

As craniostenoses representam importante grupo de alterações dismórficas fenotípicas dentro da prática clínica, resultantes do fechamento prematuro das suturas cranianas, originando alterações na orientação do crescimento e desenvolvimento normal do crânio, conforme o comprometimento de uma ou mais suturas. Mais do que comprometimento isoladamente estético, alterações neurofuncionais e cognitivas são comuns, especialmente nos casos das craniostenoses sindrômicas malformativas. Apesar dos fenótipos clínicos serem bastante conhecidos da prática médica, especialmente neu- rológica e pediátrica, atualmente o conhecimento referente aos mecanismos fisiopato- gênicos envolvidos ainda é bastante incipiente. Assim, o conhecimento dos principais modelos experimentais animais e o desenvolvimento de novos modelos dirigidos são fundamentais para a compreensão mais ampla das principais doenças que cursam com tal fenótipo. O objetivo deste artigo é fazer uma breve revisão a respeito dos principais modelos animais descritos para as craniostenoses.(AU)

Craniostenosis represents an important group of dysmorphic phenotypic changes in clinical practice, resulting from the premature closure of the cranial sutures, causing changes in the orientation of normal growth and development of the skull, according to the compromise of one or more sutures. More than aesthetic compromise alone, neurofunctional and cognitive changes are common, especially in cases of malformative syndromic craniostenosis. Despite the clinical phenotypes are well known in medical practice, mainly neurological and pediatric, the current knowledge regarding the mechanisms involved in its physiopathogenesis are still incipient. Thus, knowledge of the main experimental animal models and developing new targeted models are critical to a broader understanding of major diseases with this phenotype. The objective of this review is to briefly review the main animal models described for craniostenosis.(AU)

Effects of uterine cervix constriction on Wistar rats / Efeitos da constrição do cérvix uterino em ratos Wistar

PURPOSE: To verify if uterine cerclage can induce craniosynostosis or any cranial deformity in new born Wistar rats. METHODS: One pregnant female Wistar rat underwent laparotomy on day 18 of gestation and the uterus cervix was closed with a 3-0 nylon suture to avoid delivery, that occurs normally on the 21 day. The suture was released after 48 hours beyond the normal gestation period. The female rat delivered 11 pups. Six surviving rats from the delivery (group A - constrained group). Two rats were born from another mother and in the same age were used as control group (group B - 2 nonconstrained controls) were allowed to grow. They were sacrificed 1.2 years after their birth all the eight animals. Linear measurement, routine histology and computed tomography of the skull were performed at the time of their death to evaluate the cranial asymmetries by mesurements of the anatomical landmarks of the craniofacial skeleton of the rats on the two groups and compared then. RESULTS: We did not observe statistically significant differences in any of the compared measurements (p>0.05) obtained through the morphologic and radiologic methods. Histologic examinations did not reveal any sign of premature fusion or suture imbrications. Critical decrease in longitudinal body size was noticed as the limbs too in all the animals of group A. CONCLUSION: Constriction of uterine cervix leads to fetus suffering, even death for a few animals, associated to small body size, but not to craniosynostosis.(AU)

OBJETIVO: Verificar se a cerclagem intra-uterina pode induzir, ao nascimento de ratos Wistar, craniossinostose ou qualquer outra deformidade craniana. MÉTODOS: Uma rata Wistar prenhe foi submetida à laparotomia no 18º dia de gestação e o cérvix uterino foi suturado com 3-0 nylon, impedindo o parto normal que normalmente ocorre no 21º dia de gestação. A sutura foi liberada 48 horas após o período gestacional normal. A rata gestante deu à luz 11 animais. Seis ratos sobreviveram ao parto (grupo A com restrição). Dois ratos nascidos de outra mãe e com a mesma idade foram utilizados como controle (grupo B sem restrição controle) durante o seu crescimento. Os oito animais foram sacrificados após 1,2 ano. Medidas lineares, histologia e tomografia computadorizada foram utilizadas para a aferição de assimetrias cranianas através da mensuração de pontos anatômicos do esqueleto craniofacial dos ratos dos dois grupos. RESULTADOS: Não foi observada diferença estatisticamente significante entre as medidas obtidas nos ratos dos dois grupos (p>0,05) obtidas através de métodos morfológicos e radiológicos. As análises histológicas não revelaram sinais de fusão prematura da suturas do crânio. Diminuição do segmento corpóreo, bem como do tamanho dos membros foi evidenciado em todos os animais do grupo A. CONCLUSÃO: A restrição do cérvix uterino levou ao sofrimento fetal, morte de alguns animais e diminuição do tamanho do corpo de todos os animais, mas não craniossinostose.(AU)