Interventricular inflow time difference assessed by dual pulsed-wave Doppler echocardiography in dogs with myxomatous mitral valve disease.

INTRODUCTION: Interventricular inflow time difference (IVID), which is defined as the time interval between the opening of the mitral valve and the opening of the tricuspid valve, hold prognostic value in human patients with heart failure. Few reports regarding IVID are available in dogs. ANIMALS: Ninety dogs with myxomatous mitral valve disease (MMVD) and 47 dogs without heart disease. Dogs with MMVD received unstandardized therapy based on the stage of disease. MATERIALS AND METHODS: This was a prospective cohort study. Dogs were classified into two groups based on IVID: tricuspid opening preceding mitral opening (TOP) and mitral opening preceding tricuspid opening (MOP). The potential influence of the MOP group at enrollment on the primary outcome (cardiac-related death) was determined by Kaplan-Meier analysis. RESULTS: Almost all dogs without heart disease (97.9%) were classified in the TOP group. Twenty-nine dogs (32.2%) were classified in the MOP group. Left heart size, transmitral early diastolic inflow velocity, and right ventricular Tei index were significantly greater in the MOP group compared to those in the TOP group. Cardiac-related death were observed in 34 dogs (40.5%). The dogs in the MOP group at initial examination had shorter survival times than those in the TOP group (586 days vs. >1,831 days; 95% confidence interval, 237-714 days vs. 1,037 days to >1,831 days; P<0.001). CONCLUSIONS: Interventricular inflow time difference is potentially useful for prognostic assessments in dogs with MMVD. Further prospective studies that quantify the repeatability and influence of therapy on IVID are needed.

B-mode and Doppler ultrasonography of abdominal structures of the peccary (Tayassu tajacu, Linnaeus 1758) / [Ultrassonografias Doppler e modo-B das estruturas abdominais de catetos (Tayassu tajacu Linnaeus, 1758)]

This study used B-mode and Doppler ultrasonography to characterize the abdominal structures of healthy peccaries raised in captivity. Fifteen peccaries were used for this study. The urinary vesicle appeared as an ovoid structure, located in the abdominal and pelvic transition, with a hyperechogenic, thin, smooth, and regular wall. The kidneys presented retroperitoneal topography and had similar sizes. The kidney/aorta ratio had an average value of 10.53±15cm (right) and 10.23±0.12 (left). The right adrenal gland had a length of 1.93±0.34cm and diameter of 0.56±0.16cm. The left adrenal gland had a length of 1.85±0.42cm and diameter of 0.52±0.11cm. The spleen had a diameter of 1.13±0.18cm. The hepatic vein demonstrated polyphasic flow in pulsed Doppler, with two retrograde peaks and an anterograde peak with a flow velocity of 25.7±0.83cm/s. The abdominal aorta had a diameter of 0.58±0.05cm and a flow velocity of 115.17±5.32cm/s. The morphological and hemodynamic study of the abdominal structures of the peccary, observed through B-mode and Doppler ultrasonography, aided in identifying the size, shape, position, echogenicity, and echotexture of the abdominal organs and in making inferences about the normal parameters for these structures in this species.(AU)

Este estudo teve como objetivo utilizar as ultrassonografias de modo-B e Doppler para caracterizar as estruturas abdominais de um cateto sadio criado em cativeiro. Quinze catetos foram utilizados para este estudo. A vesícula urinária apareceu como uma estrutura ovoide, localizada na transição entre as partes abdominal e pélvica, com uma parede hiperecogênica, fina, lisa e regular. Os rins apresentaram topografia retroperitoneal e tamanhos semelhantes. A relação rim/aorta teve um valor médio de 10,53 ± 15cm (direita) e 10,23 ± 0,12cm (esquerda). A glândula adrenal direita tinha um comprimento de 1,93 ± 0,34cm e um diâmetro de 0,56 ± 0,16cm. A glândula suprarrenal esquerda tinha um comprimento de 1,85 ± 0,42cm e um diâmetro de 0,52 ± 0,11cm. O baço tinha um diâmetro de 1,13 ± 0,18cm. A veia hepática demonstrou fluxo polifásico no Doppler pulsátil, com dois picos retrógrados e um pico anterógrado com velocidade de fluxo de 25,7±0,83cm/s. A aorta abdominal tinha um diâmetro de 0,58 ± 0,05cm e uma velocidade de fluxo de 115,17±5,32cm/s. Os estudos morfológico e hemodinâmico das estruturas abdominais do queixada, observadas por meio das ultrassonografias modo-B e Doppler, auxiliaram na identificação do tamanho, da forma, da posição, da ecogenicidade e da ecotextura dos órgãos abdominais e na realização de inferências sobre os parâmetros de normalidade para as estruturas nas espécies.(AU)

Evaluation of cardioprotective effects of carvedilol in dogs receiving doxorubicin chemotherapy: A prospective, randomized, double-blind, placebo controlled pilot study.

The aim of this pilot study was to evaluate the cardioprotective effects of carvedilol in dogs receiving doxorubicin chemotherapy and provide suggestions to future studies based on results and limitations of our study. Thirteen dogs were randomized into two experimental groups: 6 dogs in carvedilol group and 7 dogs in placebo group. In carvedilol group, 0.39 mg/kg ± 0.04 twice-daily oral carvedilol was started on the day of the first doxorubicin treatment and continued throughout the chemotherapy protocol until the final cardiological evaluation. Cardiological evaluations were performed before the first doxorubicin administration and then 10 to 15 days after each subsequent dose. Troponin I and oxidative stress tests were performed with serum collected from dogs at the initial and final cardiological evaluation. Carvedilol produced some echocardiographic and electrocardiographic changes (reduced E velocity and E/IVRT ratio, as well reduced heart rate and increased PR and QT interval) due to its beta-block effect. In placebo group Doppler study showed a significant increase in mitral flow deceleration time (EDT), as well increased amplitude of the S wave in the right, and R wave in the left, precordial chest leads. There were significant difference in the EDT, E/IVRT and A' velocity, as well heart rate, PR interval and R wave in V4/CV6LU precordial chest lead between groups. In conclusion, some indexes of diastolic function and in precordial chest leads were less affected by doxorubicin in carvedilol than in control group. This suggests that carvedilol may have a beneficial effect in canine cancer patients receiving doxorubicin.

Estudo ecodopplercardiográfico em caprinos da raça Moxotó / Doppler echocardiography in goats Moxotó

Objetivou-se com este estudo reportar descrições acerca dos cortes ecocardiográficos no modo bidimensional, das dimensões cardíacas pelo modo unidimensional e dos índices de fluxo Doppler em caprinos da raça Moxotó. Foram utilizados 32 caprinos da raça Moxotó, distribuídos em quatro grupos por categoria de peso corporal, de igual número (n=8), em: G1 (5-10kg), G2 (10-15kg), G3 (15-20kg) e G4 (>20kg). Todos foram submetidos a um registro ecocardiográfico pelos modos bidimensional, modo-M, Doppler pulsado (PW), contínuo (CW) e de fluxo de cores (CF). A formação espectral das imagens ecocardiográficas foi satisfatória, contudo algumas adaptações foram necessárias para obtenção adequada dos cortes nos caprinos acima de 20 kg. Os parâmetros ecocardiográficos em modo unidimensional (IVSd, IVSs, LVIDd, LVIDs, VPWd, LVPWs) e índices de função cardíaco (EF e FS) apresentaram uma correlação descritiva positiva com peso corporal enquadradas nas categorias estudadas. A separação septal do ponto E, mostrou-se constante dentre as categorias de peso investigadas, variando entre 0,1 a 0,41cm em caprinos da raça Moxotó. A relação Em/Am foi predominantemente " >1" em todos os caprinos estudados, com Emax > Amax em todas as categorias, não sendo sujeito a influência da frequência cardíaca dentre as categorias de peso estudados. O mesmo pode ser aplicado ao TRIV, que se mostrou uniforme dentre os intervalos de peso estudados. As velocidades de fluxo da valva aórtica individuais foram superiores a velocidade máxima do fluxo da valva pulmonar. Os tempos de ejeção dos fluxos aórtico e pulmonar apresentaram correlação positiva descritiva com o aumento do peso corporal. Condição também observada sobre o VTI dos espectros de fluxo, dada a relação direta desta variável com o volume sistólico inversamente à FC. O tempo de aceleração (TA) do fluxo pulmonar foi superior ao fluxo aórtico, sendo este relação direta com aumento do peso corporal por categoria estudada e inversamente à frequência cardíaca. Desta forma, a padronização das variáveis ecodopplercardiográficas na espécie caprina, deve sempre considerar particularidades relacionadas ao padrão racial, faixa etária e peso corporal, bem como estudos de repetibilidade e reprodutibilidade e adoção de elementos individuais referenciais para elaboração confiável de valores de normalidade.(AU)

This study describes the two-dimensional echocardiographic sections, M-mode cardiac dimensions, and Doppler flow indices in Moxotó goats. A total of 32 Moxotó goats were divided into four equal groups (n = 8) according to body weight class: G1 (5-10 kg), G2 (10-15kg), G3 (15-20kg) and G4 (>20kg). All animals underwent echocardiographic tests, two-dimensional and M-mode, and pulsed (PW), continuous (CW) and color flow (CF) Doppler. The spectral formation of echocardiographic images was satisfactory, although some adjustments were necessary to obtain adequate cuts/sections for goats above 20 kg. One-dimensional echocardiographic parameters (IVSD, IVSS, LVIDd, LVIDs, VPWd, LVPWs) and cardiac function index (EF and FS) showed a positive descriptive correlation with body weight in the categories studied. The septal separation of point E was constant among the weight categories investigated, ranging from 0.1 to 0.41cm. The Em/Am ratio was predominantly ">1", with Emax> Amax in all weight categories, and not affected by the heart rate among the studied weight classes. The IVRT was also uniform among the studied weight classes. The individual flow rates of the aortic valve were higher than the maximum flow rate of the pulmonary valve. The ejection times of the aortic and pulmonary flows were positively correlated with increasing body weight, something also observed on the VTI of flow spectra, given the direct relationship of this variable with the stroke volume inversely to FC. The acceleration time (AT) of pulmonary blood flow was greater than the aortic flow, and directly related to increasing body weight and inversely with heart rate. Thus, the standardization of Doppler echocardiographic variables in goats, should always consider breed, age and body weight as well as repeatability and reproducibility studies and adoption of individual reference elements for reliable development of normal values.(AU)

Diastolic heart failure associated with hemangiosarcoma infiltrating left ventricular walls in a dog.

A 9-year-old Shetland sheepdog was diagnosed with cardiogenic pulmonary edema. Echocardiography revealed focally thickened left ventricular free wall and interventricular septum and left atrial dilation. Left ventricular systolic function was preserved. Doppler echocardiography of transmitral flow indicated restrictive left ventricular filling. Cardiac histopathology demonstrated hemangiosarcoma infiltrating the left ventricular walls.

Insuffisance cardiaque diastolique associée à l'infiltration d'un hémangiosarcome dans les parois ventriculaires gauches chez un chien. Un chien berger des Shetlands âgé de 9 ans a été diagnostiqué avec un oedème pulmonaire cardiogénique. L'échocardiographie a révélé un épaississement focal de la paroi libre du ventricule gauche et du septum interventriculaire et une dilatation atriale gauche.. La fonction systolique ventriculaire gauche était préservée. L'échographie Doppler de l'écoulement transmitral indiquait un remplissage ventriculaire gauche restreint. L'histopathologie cardiaque a démontré l'infiltration des parois ventriculaires gauches par l'hémangiosarcome.(Traduit par Isabelle Vallières).

Effect of Body Position, Exercise, and Sedation on Estimation of Pulmonary Artery Pressure in Dogs with Degenerative Atrioventricular Valve Disease.

BACKGROUND: Severity of pulmonary hypertension (PH) in dogs is related to clinical signs and prognosis. HYPOTHESIS/OBJECTIVES: We hypothesized that Doppler echocardiographic (DE) indices of pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) are influenced by independent factors that create clinically important variability of DE-based estimates of PH in dogs. ANIMALS: Thirty-eight client owned dogs with naturally acquired degenerative atrioventricular valve disease and tricuspid regurgitation (TR). METHODS: Dogs were prospectively enrolled, and target variables were acquired during 4 echocardiographic study periods (lateral recumbency, standing, lateral recumbency after a 6-minute walk test [6MWT], and lateral recumbency after sedation with butorphanol 0.25 mg/kg IM). Statistical methods included repeated measures ANOVA, mixed model analysis, and Chi-squared test of association. RESULTS: There was a significant increase in peak TR flow velocity (TRFV; P < 0.01) after sedation in 78% of dogs, with TRFV increasing by >0.4 m/s in 42% of dogs, independent of stroke volume. A significant effect of study period on DE-estimated PVR was not found (P = 0.15). There were negligible effects of sonographer, body position, and 6MWT on echocardiographic variables of PH. Clinically relevant cyclic variation of TRFV was found. There was an association between estimation of right atrial pressure based on subjective assessment and estimation based on cranial vena cava collapsibility (P = 0.03). CONCLUSIONS AND CLINICAL IMPORTANCE: The increase in TRFV observed with sedation could change assessment of PH severity and impact prognostication and interpretation of treatment response. Further studies with invasive validation are needed.

Assessment of Left Atrial Deformation and Function by 2-Dimensional Speckle Tracking Echocardiography in Healthy Dogs and Dogs With Myxomatous Mitral Valve Disease.

BACKGROUND: The assessment of left atrial (LA) function by 2-dimensional speckle tracking echocardiography (STE) holds important clinical implications in human medicine. Few similar data are available in dogs. OBJECTIVES: To assess LA function by STE in dogs with and without myxomatous mitral valve disease (MMVD), analyzing LA areas, systolic function, and strain. ANIMALS: One hundred and fifty dogs were divided according to the American College of Veterinary Internal Medicine classification of heart failure: 23 dogs in class A, 52 in class B1, 36 in class B2, and 39 in class C + D. METHODS: Prospective observational study. Conventional morphologic and Doppler variables, LA areas, and STE-based LA strain analysis were performed in all dogs and results were compared among groups. Correlation analysis was carried out between LA STE variables and other echocardiographic variables. RESULTS: Variability study showed good reproducibility for all the tested variables (coefficient of variation <16%). Left atrial areas, fractional area change, peak atrial longitudinal strain (PALS), peak atrial contraction strain, and contraction strain index (CSI) differed significantly between groups B2 and C + D and all the other groups (overall P < .001), whereas only PALS differed between groups B1 and A (P = .01). Left atrial areas increased with progression of the disease, whereas LA functional parameters decreased. Only CSI increased nonsignificantly from group A to group B1 and then progressively decreased. Thirty-one significant correlations (P < .001, r > .3) were found between conventional left heart echocardiographic variables and LA areas and strain variables. CONCLUSIONS AND CLINICAL IMPORTANCE: Left atrial STE analysis provides useful information on atrial function in the dog, highlighting a progressive decline in atrial function with worsening of MMVD.

Influence of alterations in heart rate on left ventricular echocardiographic measurements in healthy cats.

Objectives The purpose of this study was to evaluate the effect of sudden alterations in heart rate (HR) on left ventricular (LV) wall thickness and dimensions determined by echocardiography in healthy cats. Methods Six experimental cats were used. All cats were anaesthetised and HR was controlled with right atrial pacing. The interventricular septum and left ventricular free wall thickness at end diastole (IVSd and LVFWd, respectively), left ventricular end-diastolic and end-systolic diameter (LVIDd and LVIDs, respectively) and shortening fraction (FS) of each cat were assessed using echocardiography at pacing rates of 120, 130, 140, 150, 160, 170 and 180 ppm. Results There were significant relationships between HR and IVSd, LVFWd, LVIDd, LVIDs and FS. As the HR increased, LV wall thickness increased and chamber dimensions got smaller in a linear fashion. The maximum and minimum differences in wall thickness between 120 ppm and 180 ppm were 2.0 mm and 0.7 mm in single measurements, respectively. Conclusions and relevance LV wall thickness and dimensions were significantly influenced by alterations in HR.

Utility of Tissue Doppler Imaging in the Echocardiographic Evaluation of Left and Right Ventricular Function in Dogs with Myxomatous Mitral Valve Disease with or without Pulmonary Hypertension.

BACKGROUND: In human medicine, right ventricular (RV) functional parameters represent a tool for risk stratification in patients with congestive heart failure caused by left heart disease. Little is known about RV alterations in dogs with left-sided cardiac disorders. OBJECTIVES: To assess RV and left ventricular (LV) function in dogs with myxomatous mitral valve disease (MMVD) with or without pulmonary hypertension (PH). ANIMALS: One-hundred and fourteen dogs: 28 healthy controls and 86 dogs with MMVD at different stages. METHODS: Prospective observational study. Animals were classified as healthy or having MMVD at different stages of severity and according to presence or absence of PH. Twenty-eight morphological, echo-Doppler, and tissue Doppler imaging (TDI) variables were measured and comparison among groups and correlations between LV and RV parameters were studied. RESULTS: No differences were found among groups regarding RV echo-Doppler and TDI variables. Sixteen significant correlations were found between RV TDI and left heart echocardiographic variables. Dogs with PH had significantly higher transmitral E wave peak velocity and higher E/e' ratio of septal (sMV) and lateral (pMV) mitral annulus. These 2 variables were found to predict presence of PH with a sensitivity of 84 and 72%, and a specificity of 71 and 80% at cut-off values of 10 and 9.33 for sMV E/e' and pMV E/e', respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: No association between variables of RV function and different MMVD stage and severity of PH could be detected. Some relationships were found between echocardiographic variables of right and left ventricular function.

Prospective evaluation of Doppler echocardiography, tissue Doppler imaging and biomarkers measurement for the detection of doxorubicin-induced cardiotoxicity in dogs: A pilot study.

The purpose of this pilot study was to evaluate the usefulness of selected echocardiographic parameters, NT-proBNP and cardiac troponin I (cTnI) in the detection of cardiotoxicity in dogs treated with doxorubicin for various malignancies. Echocardiographic studies and biomarker measurements were performed before each administration of doxorubicin, then 1 and 3 months after completion of therapy. Thirteen dogs were included, with a total cumulative dose of doxorubicin ranging from 30 to 150 mg/m(2). E/A ratio significantly decreased during doxorubicin administration (p=0.047). cTnI level was also significantly affected by treatment (p=0.046), increasing above normal at least at one time point in 11 of 13 dogs. The results of this pilot study suggest that monitoring of left ventricular diastolic function and cTnI level measurement might be useful in the early detection of cardiotoxic signs of doxorubicin therapy in dogs.

Short-term follow-up of exercise training program and beta-blocker treatment on quality of life in dogs with naturally acquired chronic mitral valve disease

This study aimed to evaluate the effects of carvedilol treatment and a regimen of supervised aerobic exercise training on quality of life and other clinical, echocardiographic, and biochemical variables in a group of client-owned dogs with chronic mitral valve disease (CMVD). Ten healthy dogs (control) and 36 CMVD dogs were studied, with the latter group divided into 3 subgroups. In addition to conventional treatment (benazepril, 0.3-0.5 mg/kg once a day, and digoxin, 0.0055 mg/kg twice daily), 13 dogs received exercise training (subgroup I; 10.3±2.1 years), 10 dogs received carvedilol (0.3 mg/kg twice daily) and exercise training (subgroup II; 10.8±1.7 years), and 13 dogs received only carvedilol (subgroup III; 10.9±2.1 years). All drugs were administered orally. Clinical, laboratory, and Doppler echocardiographic variables were evaluated at baseline and after 3 and 6 months. Exercise training was conducted from months 3-6. The mean speed rate during training increased for both subgroups I and II (ANOVA, P>0.001), indicating improvement in physical conditioning at the end of the exercise period. Quality of life and functional class was improved for all subgroups at the end of the study. The N-terminal pro-brain natriuretic peptide (NT-proBNP) level increased in subgroup I from baseline to 3 months, but remained stable after training introduction (from 3 to 6 months). For subgroups II and III, NT-proBNP levels remained stable during the entire study. No difference was observed for the other variables between the three evaluation periods. The combination of carvedilol or exercise training with conventional treatment in CMVD dogs led to improvements in quality of life and functional class. Therefore, light walking in CMVD dogs must be encouraged.

Plasma atrial natriuretic peptide is an early diagnosis and disease severity marker of myxomatous mitral valve disease in dogs.

The aim of this study was to retrospectively assess the clinical usefulness of plasma atrial natriuretic peptide (ANP) concentrations for determining the severity of myxomatous mitral valve disease (MMVD) in dogs. Plasma ANP levels were found to be significantly higher in dogs with MMVD compared to healthy dogs, and plasma ANP levels increased significantly in dogs with progressive heart failure. In dogs with MMVD, stepwise regression analysis revealed that the left atrium/aorta ratio and fractional shortening could be used to predict the plasma ANP concentration. These results indicated that plasma ANP rose with an increase in the volume overload of the left side of the heart. Plasma ANP discriminated cardiomegaly from non-cardiomegaly caused by asymptomatic MMVD. We conclude, therefore, that plasma ANP concentrations may be a clinically useful tool for early diagnosis of asymptomatic MMVD in dogs.

Effect of heart failure on dipeptidyl peptidase IV activity in plasma of dogs.

BACKGROUND: In congestive heart failure (HF), plasma B-type natriuretic peptide (BNP) seems devoid of biological effectiveness. BNP(1-32) could be truncated into BNP(3-32) by dipeptidyl peptidase IV (DPP4), and BNP(3-32) has reduced biological activities. HYPOTHESIS: Increased DPP4 activity is associated with pathophysiology of HF. ANIMALS: One hundred twenty-eight client-owned dogs and 9 experimental Beagles from the Clinical Veterinary Unit of the University of Liège. METHODS: We prospectively measured plasma DPP4 activity in 5 groups of dogs: normal growing dogs (n = 21), normal adult dogs (n = 60), healthy Beagle (n = 9), dogs with myxomatous mitral valve disease (n = 35), and dogs with dilated cardiomyopathy (n = 12). The final diagnosis and the severity of HF were determined by Doppler echocardiography. Plasma DPP4 activity was measured kinetically by a fluorimetric method. RESULTS: In growing dogs, DPP4 activity was higher than in adults (P < .001) and inversely correlated with age (r = -0.57, P < .01). In adults, DPP4 activity increased linearly with body weight (r = 0.39, P < .01), but there was no influence of age or sex. No effect of the circadian rhythm was noted. DPP4 activity was significantly higher in HF ISACHC I (16.3 ± 1.14 U/L) compared with healthy adults (12.4 ± 0.65 U/L, P < .05) and HF ISACHC III (11.0 ± 1.50 U/L, P < .05). Mean DPP4 activity in ISACHC II was 15.1 ± 1.4 U/L. CONCLUSION AND CLINICAL IMPORTANCE: We did not find evidence that plasma DPP4 activity is responsible for the "BNP resistance" in overt congestive HF, but it may be implicated in early stages.

Systemic inflammation and endothelial dysfunction in dogs with congestive heart failure.

BACKGROUND: Congestive heart failure (CHF) is associated with endothelial dysfunction in people and in dogs with experimentally induced CHF, but this is not well characterized in dogs with naturally occurring CHF. HYPOTHESIS/OBJECTIVES: To evaluate endothelial function via assessment of reactive hyperemia (RH) in healthy dogs and dogs with CHF, and to assess for relationships with plasma biomarkers of vascular function and clinical markers of disease severity. ANIMALS: Twenty client-owned animals with CHF due to myxomatous mitral valve disease (n = 15) or dilated cardiomyopathy (n = 5) and 17 healthy control dogs. METHODS: Prospective case-controlled observational study. Dogs underwent blood sampling, echocardiography, and Doppler assessment of brachial artery velocity (VTI) at baseline and during reactive hyperemia (RH-VTI). RH-VTIs between control dogs and dogs with CHF were compared, and the relationships between RH-VTI, clinical parameters, and plasma biomarkers were assessed. RESULTS: Dogs with CHF (96.5 ± 51.7%) had an attenuated % increase in VTI during RH compared to healthy controls (134.8 ± 58.7%; P = .04). Increasing ISACHC class (R(2) = 0.24; P = .004), plasma NT-proBNP (R(2) = 0.15; P = .03) and CRP (R(2) = 0.2; P = .02) were associated with reduced RH-VTI. Increased plasma CRP, NO(x) , and NT-proBNP concentrations were found in dogs with CHF (P < .02 for all). No differences were detected in other plasma markers. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with CHF have an attenuated RH response, and increased plasma CRP and NO(x) concentrations. Doppler assessment of RH velocity could represent a novel noninvasive method of evaluating endothelial function in the dog.

Doppler echocardiographic diagnosis and surgical therapy of constrictive pericarditis in a cat.

A 4-year-old Ragdoll cat presented for dyspnea secondary to chylous pleural effusion to the University of Georgia Veterinary Teaching Hospital. Physical examination, complete blood count, serum chemistries, urinalysis, thoracic radiographs, abdominal radiographs, and thoracic fluid cytology and culture failed to identify an etiology for the chylous effusion. The patient tested negative for feline leukemia virus, feline immunodeficiency virus and heartworm disease. Respiration phasic influences on early diastolic trans-mitral, trans-tricuspid and pulmonary vein blood flow velocities during Doppler echocardiography were consistent with constrictive pericarditis. The cat underwent subtotal pericardectomy. The patient recovered without complication and is overtly healthy without radiographic or echocardiographic abnormalities 6-months post-surgery. Constrictive pericarditis should be considered in cats with idiopathic pleural effusion, with or without ascites, in which standard echocardiographic assessment is not suggestive of structural heart disease. If constrictive pericarditis is present, the Doppler characteristics outlined here may allow for this diagnosis to be made. Pericardectomy may be highly rewarding, although the specific etiology of the constrictive pericarditis may remain unknown.

Ventricular septal defect with aortic valve insufficiency in a New Zealand White rabbit.

A heart murmur was detected in a 10 mo old, female New Zealand White rabbit. Auscultation revealed cardiac murmurs both at the left and right hemithorax. Phonocardiography confirmed the systolic-diastolic nature of the left-sided and the systolic character of the right-sided murmur. Electrocardiography showed normal sinus rhythm; tall R waves and large T waves in lead II; and deep S waves in leads II, III, and aVF. Thoracic radiography demonstrated generalized cardiomegaly with prominent pulmonary vasculature. Echocardiography revealed a perimembraneous ventricular septal defect with aortic insufficiency. Signs of biventricular volume overload, relative pulmonic stenosis, and pulmonary valve insufficiency were also seen as consequences of the defect. Necropsy demonstrated a ventricular septal defect just below the aortic valve, a dilated pulmonary trunk, dilated and hypertrophied ventricles, dilated atria, and rightward displacement of the aortic root. Cardiac histopathology showed ventricular cardiomyocyte degeneration (swelling and hypereosinophilia of the cytoplasm with a loss of cross striation, and nuclear hyperchromasia), cartilaginous metaplasia of the aorta, and subendocardial fibrosis of the right ventricular flow tract.

Outcome in 55 dogs with pulmonic stenosis that did not undergo balloon valvuloplasty or surgery.

OBJECTIVE: To determine the outcome, independent predictors of cardiac death, and the Doppler-derived pressure gradient cut-off for predicting cardiac death in dogs with pulmonic stenosis, with or without tricuspid regurgitation, that do not undergo balloon valvuloplasty or valve surgery. METHODS: Review of medical records of two UK referral centres between July 1997 and October 2008 for all cases of pulmonic stenosis that had no balloon valvuloplasty or valve surgery. Inclusion criteria included a diagnosis of pulmonic stenosis; spectral Doppler pulmonic velocity greater than 1·6 m/s; characteristic valve leaflet morphological abnormalities. Exclusion criteria included concurrent significant cardiac defects, including tricuspid dysplasia. Dogs with tricuspid regurgitation were included. Dogs were classified according to Doppler-derived pressure gradients into mild, moderate or severe pulmonic stenosis categories. RESULTS: Presence of tricuspid regurgitation and severe stenosis were independent predictors of cardiac death. A pulmonic pressure gradient of more than 60 mmHg was associated with 86% sensitivity, and 71% specificity of predicting cardiac death. CLINICAL SIGNIFICANCE: There is an increased probability of cardiac death in those cases which have a pulmonary pressure gradient greater than 60 mmHg and tricuspid regurgitation, though the effect of severity of tricuspid regurgitation on outcome was not measurable because of small sample sizes. These animals might benefit from intervention.

Transthoracic echocardiographic guidance of patent ductus arteriosus occlusion with an Amplatz® canine duct occluder.

Placement of an Amplatz canine duct occluder (ACDO) is usually performed by fluoroscopy (Nguyenba and Tobias, 2007). The latter technical approach presents limitations, mostly due to radiation exposure, making this practice dangerous for the patient and operators. In this study, we describe the successful placement of an Amplatz Canine Duct Occluder device by using transthoracic echocardiographic (TTE) guidance, performed on an 11-month-old female mongrel dog with a grade VI/VI continuous heart murmur diagnosed with patent ductus arteriosus (PDA). The TTE is useful in eliminating exposure to radiation and is more versatile than fluoroscopy in conveying real-time detailed information concerning the position of the ACDO.

Caracterização clínica da cardiomiopatia chagásica crônica em cães / Clinical characterization of chronic chagasic cardiomyopathy in dogs

On the American continent, almost 15 million people are affected by Chagas disease, resulting in important economic and social damages. Dogs are considered to be an excellent experimental model to study Chagas' disease; as a result, in this research, the characterization of cardiovascular abnormalities was performed in dogs experimentally infected with Trypanosoma cruzi (the Colombian strain) that were at chronic stage. Thirteen adult female dogs were evaluated by electrocardiographic, echocardiographic, hematological and biochemical analyses in the chronic phase. For the electrocardiographic studies, respiratory sinus arrhythmia was the predominant rhythm during the entire research period (49.55 percent to 67 percent), with a low prevalence of right bundle branch block (0-13 percent) and first-degree atrioventricular block (0-14 percent). The spectral Doppler echocardio-graphy showed E and A mitral wave reversal (0.71±0.17), confirming the diastolic dysfunction present in all dogs. An increase in the enzymes activities was detected in the serum analysis, indicating myocardial injury by the infection. Six dogs died during the follow-up. In this way, the clinical characterization of experimentally infected dogs, as described here, increases the knowledge and allows for recognition of the behavioural modifications present in Chagas' disease in affected dogs.

No continente Americano, aproximadamente 15 milhões de pessoas são afetadas pela doença de Chagas, ocasionando importantes danos econômicos e sociais. O cão é considerado excelente modelo experimental para o estudo dessa enfermidade; assim sendo, foram caracterizadas, neste ensaio, as anormalidades cardiovasculares de 13 cães experimentalmente infectados com a cepa Colombiana do Trypanosoma cruzi, em fase crônica (1997-2004). Ao eletrocardiograma, a arritmia sinusal respiratória foi o ritmo predominante durante todo período experimental (49,55-67 por cento), com baixas prevalências de bloqueio de ramo direito (0-13 por cento) e de bloqueio atrioventricular de primeiro grau (0-14 por cento). A EcoDopplercardiografia espectral revelou inversão das ondas E e A mitral (0.71±0.17), confirmando a disfunção diastólica presente em todos os cães avaliados. O aumento da atividade enzimática sérica foi detectado, indicando agressão miocárdica pela infecção. Seis cães morreram durante o período experimental. Desta forma, a caracterização clínica dos cães experimentalmente infectados trouxe informações importantes, possibilitando reconhecer o comportamento clínico dessa importante infecção, na espécie canina.

Tissue Doppler and strain imaging in dogs with myxomatous mitral valve disease in different stages of congestive heart failure.

BACKGROUND: Tissue Doppler imaging (TDI) including strain and strain rate (SR) assess systolic and diastolic myocardial function. HYPOTHESIS: TDI, strain, and SR variables of the left ventricle (LV) and the interventricular septum (IVS) differ significantly between dogs with myxomatous mitral valve disease (MMVD) with and without congestive heart failure (CHF). ANIMALS: Sixty-one dogs with MMVD with and without CHF. Ten healthy control dogs. METHODS: Prospective observational study. RESULTS: Radial motion: None of the systolic variables were altered and 3 of the diastolic velocities were significantly increased in dogs with CHF compared with dogs without CHF and control dogs. Longitudinal motion: 2 systolic velocities and 3 diastolic velocities were significantly increased in dogs with CHF compared with dogs without CHF and control dogs. Difference in systolic velocity time-to-peak between LV and IVS was significantly increased in dogs with MMVD with and without CHF compared with control dogs. In total, 11 (23%) of 48 TDI and strain variables differed significantly between groups. Left atrial to aortic ratio was positively correlated to early diastolic velocities, percentage increase in left ventricular internal diameter in systole was positively correlated to systolic and diastolic velocities, and mitral E wave to peak early diastolic velocity in the LV basal segment (E/Em) was positively correlated to radial strain and SR. CONCLUSIONS AND CLINICAL IMPORTANCE: Few TDI and strain variables were changed in dogs with MMVD with and without CHF. Intraventricular dyssynchrony may be an early sign of MMVD or may be an age-related finding.