Clinical assessment of systolic myocardial deformations in dogs with chronic mitral valve insufficiency using two-dimensional speckle-tracking echocardiography

ObjectiveThe objective of this study was to clinically assess myocardial deformations in dogs with chronic mitral valve insufficiency (CMVI) using two-dimensional speckle-tracking echocardiography (2D-STE).Animals87 dogs with CMVI.MethodsDogs were placed into 1 of 3 classes, based on the International Small Animal Cardiac Health Council classification. In addition, 20 weight- and age-matched healthy dogs were enrolled as controls. The dogs were examined for myocardial deformations using 2D-STE, and strain and strain rate in the longitudinal, circumferential, and radial directions were evaluated.ResultsClass II and III dogs had higher circumferential strain than class I dogs (P = 0.002 and P = 0.001, respectively) and controls (P < 0.001 and P < 0.001, respectively). Class III dogs had higher radial strain than class I dogs (P = 0.001) and controls (P < 0.001). Class III dogs had higher radial strain rate than class I dogs (P = 0.006) and controls (P = 0.001). Other deformations, including longitudinal deformations, were not significantly different between classes of CMVI or between CMVI dogs and controls.ConclusionsIn the clinical progression of CMVI in dogs, myocardial deformations, as assessed by 2D-STE, differed according to myocardial contractile direction. Thus, assessments of multidirectional myocardial deformations may be important for better assessment of clinical cardiac function in dogs with CMVI.     

Influence of heart rate on myocardial function using two-dimensional speckle-tracking echocardiography in healthy dogs

ObjectiveThe objective of this study was to evaluate the influence of heart rate (HR) on myocardial function assessed by two-dimensional speckle-tracking echocardiography (2D-STE) in healthy dogs.AnimalsThirteen healthy beagle dogs.MethodsAnimals were anesthetized and HR was controlled with right atrial pacing. Myocardial function of each dog was assessed using 2D-STE at pacing rates of 120, 140, 160, and 180 bpm.ResultsAll strain and strain rate variables in the longitudinal, circumferential, and radial directions were not significantly different between pacing rates. Peak early diastolic torsion rate at 180 bpm was significantly increased compared with that at 120 bpm (P = 0.003).ConclusionTorsion rate in early diastole was elevated at 180 bpm, which may reflect improved myocardial relaxation with higher HR. Changes in left ventricular torsion during tachycardia may play an important role in preserving stroke volume in the presence of shortened ejection and filling times.     

Noninvasive Clinical Assessment of Systolic Torsional Motions by Two‐Dimensional Speckle‐Tracking Echocardiography in Dogs with Myxomatous Mitral Valve Disease

Background

Left ventricular torsional motion plays an important role for effective pump function. However, noninvasive clinical assessment of torsional deformations by two‐dimensional speckle‐tracking echocardiography (2D‐STE) in dogs with myxomatous mitral valve disease (MMVD) has not been reported.

Hypothesis

Left ventricular torsion is determined by the native orientation of the helical myocardial fibers, such that it might provide better assessment of myocardial function than conventional methods.

Animals

Sixty‐seven client‐owned dogs with MMVD were classified into 3 classes based on the International Small Animal Cardiac Health Council classification and 16 weight‐ and age‐matched healthy dogs.

Methods

Dogs were examined for myocardial deformations by 2D‐STE and were evaluated for peak systolic rotation and rotation rate at each basal and apical view. Dogs also were evaluated for peak systolic torsion and torsion rate.

Results

Peak systolic torsion was higher in class II than in class I (P < .001) dogs. Peak systolic torsion was lower in class III than in class II (P = .001) dogs and controls (P = .003).

Conclusions and Clinical Importance

Torsional deformations assessed by 2D‐STE differed among clinical classes of MMVD. Myocardial torsional deformations by 2D‐STE may provide more detailed assessment of contractile function in dogs with MMVD.     

Effect of torsemide and furosemide on clinical,laboratory, radiographic and quality of life variables in dogs with heart failure secondary to mitral valve disease

ObjectivesDiuretic therapy reduces preload and relieves congestion secondary to cardiac dysfunction. Torsemide (torasemide) is a loop diuretic with longer duration of action, decreased susceptibility to diuretic resistance, and adjunctive aldosterone antagonist properties compared with furosemide. We hypothesized that torsemide would be well tolerated and no less effective than furosemide at diuresis, control of clinical signs, and maintenance of quality of life (QOL) in dogs with congestive heart failure (CHF).Animals, materials and methodsSeven client-owned dogs with stable CHF receiving twice daily oral furosemide and adjunctive medications. Utilizing a double-blinded, randomized, crossover design, dogs were administered either oral furosemide at their current dose or an equivalent oral dose of torsemide (1/10 of the daily furosemide dose divided into twice daily dosing) on day 0. Crossover occurred at day 7 and the study ended on day 14. Clinical, laboratory, radiographic, and QOL variables were evaluated on days 0, 7 and 14.ResultsNo dogs developed recurrent CHF during the study. Mean furosemide dose on day 0 was 5.13 mg/kg/day (range 2.8–9.6). Following torsemide treatment, creatinine (P = 0.020), urea nitrogen (P = 0.013), phosphorus (P = 0.032), albumin (P = 0.019), carbon dioxide (P = 0.015) and anion gap (P = 0.005) were significantly increased, and urine specific gravity (P = 0.004) and chloride (P = 0.021) were significantly decreased compared with furosemide dosing. No differences in QOL were found.ConclusionsResults indicate that torsemide is equivalent to furosemide at controlling clinical signs of CHF in dogs and is likely to achieve greater diuresis vs. furosemide. Larger clinical trials evaluating torsemide as a first or second-line loop diuretic for congestive heart failure in dogs are warranted.     

Effect of azotemia on serum N-terminal proBNP concentration in dogs with normal cardiac function: A pilot study

ObjectivesTo evaluate amino-terminal pro-B type natriuretic peptide (NT-proBNP) concentration in dogs with renal dysfunction and normal cardiac structure and function.AnimalsEight dogs with renal disease, 23 healthy control dogs.MethodsSerum NT-proBNP concentration was measured in healthy dogs and dogs with renal disease using an ELISA validated for use in dogs. Affected dogs were eligible for inclusion if renal dysfunction was diagnosed based on urinalysis and serum chemistry, and if they were free of cardiovascular disease based on physical exam, systolic blood pressure, and echocardiography.ResultsThe geometric mean serum NT-proBNP concentration was significantly higher in dogs with renal disease (617 pmol/L; 95% CI, 260–1467 pmol/L) than in healthy control dogs (261 pmol/L; 95% CI, 225–303 pmol/L; P = 0.0014). There was a modest positive correlation between NT-proBNP and BUN and creatinine. Median NT-proBNP concentration was not significantly different between groups when indexed to BUN (median NT-proBNP:BUN ratio; renal, 14.2, IQR, 3.93–17.7 vs. control, 16.3, IQR, 9.94–21.2; P = 0.29) or creatinine (median NT-proBNP:creatinine ratio; renal, 204, IQR, 72.6–448 vs. control, 227, IQR, 179–308; P = 0.67).ConclusionDogs with renal disease had significantly higher mean serum concentration of NT-proBNP than control dogs. Renal function should be considered when interpreting NT-proBNP results as concentrations may be falsely elevated in dogs with renal dysfunction and normal cardiac function. The effect of renal disease was lessened by indexing NT-proBNP to BUN or creatinine. Future studies in dogs with both renal and heart disease are warranted.     

Dobutamine Stress Echocardiography for Assessment of Systolic Function in Dogs with Experimentally Induced Mitral Regurgitation

Background

Systolic dysfunction is associated with poor outcomes in dogs with myxomatous mitral valve disease. However, assessment of systolic variables by conventional echocardiographic methods is difficult in these dogs because of mitral regurgitation (MR).

Hypothesis

We hypothesized that assessment of systolic function by dobutamine stress may identify systolic dysfunction in dogs with MR, and that 2‐dimensional speckle‐tracking echocardiography (2D‐STE) could quantitatively evaluate myocardial function.

Animals

Anesthetized dogs with experimentally induced MR.

Methods

Dogs were examined for systolic myocardial deformations using 2D‐STE during dobutamine infusion before and 3 and 6 months after MR induction. We evaluated peak systolic rotation and rotation rate in each basal and apical view; peak systolic torsion and torsion rate were also calculated.

Results

Invasive peak positive first derivatives of left ventricular pressure (dp/dt) were significantly decreased in dogs 6 months after induction of MR compared with pre‐MR results. After 3 and 6 months of MR, dogs had diminished peak systolic torsion values and torsion rates in response to dobutamine infusion compared with pre‐MR results (3 months, P < .001 and P = .006; 6 months, P = .003 and P = .021). These results were significantly correlated with overall invasive dp/dt (r = 0.644, P < .001; r = 0.696, P < .001).

Conclusions and Clinical Importance

Decreased torsion during dobutamine infusion in dogs with MR may reflect latent systolic dysfunction. Dobutamine infusion, therefore, may be useful for the assessment of systolic function in dogs with MR.     

Association of diet with clinical outcomes in dogs with dilated cardiomyopathy and congestive heart failure

IntroductionDilated cardiomyopathy (DCM) in dogs has been associated with feeding of grain-free (GF), legume-rich diets. Some dogs with presumed diet-associated DCM have shown improved myocardial function and clinical outcomes following a change in diet and standard medical therapy.HypothesisPrior GF (pGF) diet influences reverse cardiac remodeling and clinical outcomes in dogs with DCM and congestive heart failure (CHF).Animals and methodsA retrospective study was performed with 67 dogs with DCM and CHF for which diet history was known. Dogs were grouped by diet into pGF and grain-inclusive (GI) groups. Dogs in the pGF group were included if diet change was a component of therapy. Survival was analyzed using Kaplan–Meier curves and the Cox proportional-hazards model.ResultsThe median survival time was 344 days for pGF dogs vs. 253 days for GI dogs (P = 0.074). Statistically significant differences in median survival were identified when the analysis was limited to dogs surviving longer than one week (P = 0.033). Prior GF dogs had a significantly worse outcome the longer a GF diet was fed prior to diagnosis (P = 0.004) or if they were diagnosed at a younger age (P = 0.017). Prior GF dogs showed significantly greater improvement in normalized left ventricular internal diastolic diameter (P = 0.038) and E-point septal separation (P = 0.031) measurements and significant decreases in their furosemide (P = 0.009) and pimobendan (P < 0.005) dosages over time compared to GI dogs.ConclusionsPrior GF dogs that survived at least one week after diagnosis of DCM, treatment of CHF, and diet change had better clinical outcomes and showed reverse ventricular remodeling compared to GI dogs.     

Ultrasonographic measurement of flow-mediated vasodilation in dogs with chronic valvular disease

ObjectivesTo measure flow-mediated vasodilation (FMD) in healthy dogs and in client-owned dogs with chronic valvular disease (CVD) and to investigate possible correlations between markers of CVD severity and FMD.AnimalsTwelve dogs with CVD and 11 healthy weight-matched dogs.MethodsBrachial artery FMD following 5 min inflation of a cuff around the antebrachium was measured in 12 dogs with CVD and 11 healthy weight-matched dogs. Measurements were also obtained in the healthy dogs 5 min after cuff placement but without inflation (‘sham cuff placement’). Dogs with CVD underwent echocardiography to confirm and characterize their disease.ResultsIn healthy dogs (median age 4 [2–6] years), median FMD was 7.7% versus 3.4% with sham cuff placement (P = 0.003). In dogs with CVD (median age 8 [4–16] years) median FMD was 5.5% versus 7.7% in healthy dogs (P = 0.131). FMD showed an inverse correlation with left ventricular end-diastolic diameter normalized for body weight (r = ?0.76, P = 0.0043).ConclusionsBrachial FMD in dogs with early CVD inversely correlates with severity of left ventricular remodelling.     

Assessment of left ventricular function by two-dimensional speckle-tracking echocardiography in small breed dogs with hyperadrenocorticism

Background

Hyperadrenocorticism (HAC) is associated with an increased prevalence of hypertension. This study investigated the left ventricular function using two-dimensional speckle-tracking echocardiography (2D-STE) in small breed dogs affected with spontaneous HAC.Age-matched healthy controls (n = 9), dogs with pituitary-dependent hyperadrenocorticism (PDH, n = 10), and dogs with adrenal-dependent hyperadrenocorticism (ADH, n = 9) were included in this study. Conventional echocardiography, global longitudinal and circumferential strain, and strain rate were assessed.

Results

On group-wise comparison, left ventricular free wall (LVFWd) and interventricular septal thickness in diastole (IVSd) were thickest in the ADH group, followed by the PDH and controls (P = 0.014 and P = 0.001, respectively). Neither LVFWd nor IVSd was correlated with systemic blood pressure (P = 0.238 and P = 0.113, respectively). The values of all variables derived from the global strain and strain rate in longitudinal and circumferential directions followed the same pattern: highest in the controls, followed by PDH and then ADH (all P < 0.05, respectively). On multiple regression analyses, global longitudinal strain, global longitudinal strain rate in systole and early diastole, and global circumferential strain all decreased linearly with increased IVSd (all P < 0.05).

Conclusions

Left ventricular hypertrophy (LVH) was more prevalent in the HAC group compared to the control group. Association between hypertension and development of LVH was not identified. Decreased global longitudinal and circumferential strains were associated with increased IVSd. 2D-STE revealed significant decreases in systolic functions that were undetected using conventional echocardiography in the ADH and PDH groups.     

Determination of the prevalence of whole blood taurine in Irish wolfhound dogs with and without echocardiographic evidence of dilated cardiomyopathy

ObjectivesTaurine plays an important role in maintaining myocardial function. Irish wolfhound dogs (IW) are at risk for dilated cardiomyopathy (DCM), but a relationship between whole blood taurine (WBT) deficiency and DCM has not been established. Our aim was to determine prevalence of WBT deficiency in IW with and without DCM and assess its association with diet.Animals115 privately owned IW.MethodsWhole blood taurine was measured in IW that received cardiovascular examination. Dietary history was recorded; crude protein and energy intake were estimated.ResultsForty-nine (42.6%) had DCM; 66 (57.4%) had no DCM. Dogs with DCM were older ([median; inter-quartile range or IQR] 5.3; 4.3, 6.2 years) than dogs without heart disease (3; 2, 4 years; P < 0.001). There was no significant relationship between WBT concentration and age (P = 0.64). Whole blood taurine was severely reduced (<130 nmol/mL) in 8 dogs (4 with and 4 without DCM) and moderately reduced (130–179.9 nmol/mL) in 32 dogs (12 with DCM and 20 without DCM). Follow up of dogs without DCM revealed that a higher proportion of dogs with any degree of WBT deficiency developed DCM later compared to dogs with normal WBT (P < 0.001).ConclusionsWhole blood taurine deficiency occurred in IW with and without DCM. Based on taurine measurement on a single occasion, there was no clear relationship between low WBT and presence of DCM in this population. Regardless of WBT, DCM affected predominantly older dogs, suggesting a relatively late onset disease in the IW.     

The effect of a pressure wrap (ThunderShirt®) on heart rate and behavior in canines diagnosed with anxiety disorder

The effect of moderate-to-deep pressure on soft tissue has been studied in both humans and nonhuman animals with positive results shown in reducing anxiety and promoting relaxation. Canine anxiety disorders are often treated with medications and behavior modification programming. Pressure wraps are sometimes used to treat canine anxiety, but the effects of this investigation have not been rigorously investigated. The aims of this study were to investigate the use of a pressure wrap (ThunderShirt®; ThunderWorks, Durham, NC) on heart rate and behavior in dogs diagnosed with an anxiety disorder. Subjects were 90 dogs (39 males and 51 females) that were diagnosed with Separation Anxiety or Generalized Anxiety Disorder. Dogs were randomly assigned to 1 of the 3 groups, namely Experimental Group 1 (dogs wore the ThunderShirt® per manufacturer's recommendations), Experimental Group 2 (dogs wore the ThunderShirt® loosely without pressure), and Control Group (dogs had no specific treatment). Average and maximum heart rates were measured at baseline and after 15 minutes alone in the kennel. Dogs were video-recorded and analysis completed for 12 behaviors, namely pacing, panting, yawning, tongue-flicking, drooling, elimination, barking, stress whining, howling, licking, door orientation, and calmness. The results were as follows: Dogs in Experimental Group 1 showed significantly less increase from baseline in average heart rate than the Control Group dogs (P < 0.001) and dogs in Experimental Group 2 (P < 0.001). Dogs in Experimental Group 1did not differ significantly from Control Group dogs in maximum heart rate when all dogs were considered, but did differ significantly from the Control Group (P = 0.04) when only those dogs not currently on anxiety medication were considered. There were no statistically significant differences among groups on behavioral outcomes, except that the dogs in the Control Group were significantly more likely to orient toward the door than the dogs in both Experimental Groups 1 (OR = 7.46, P = 0.01) and 2 (OR = 4.42, P = 0.04). Dogs in the Experimental Group 1 presented a trend of less tongue-flicking (P = 0.06) and yawning (P = 0.07) stress reduction behaviors when compared with the other 2 groups. More research should be conducted with the ThunderShirt® on behavioral outcomes. The ThunderShirt® can be used with behavior modification programming and medication as an adjunct treatment option to assist dogs diagnosed with anxiety disorder to reduce heart rate.     

Cardiomyocyte calcium cycling in a naturally occurring German shepherd dog model of inherited ventricular arrhythmia and sudden cardiac death

ObjectiveTo further characterize arrhythmic mechanisms in German shepherd dogs (GSDs) affected with inherited ventricular arrhythmias by evaluating intracellular calcium cycling and expression of calcium handling genes.AnimalsTwenty five GSDs, 9 backcross dogs, and 6 normal mongrel dogs (controls) were studied. The GSDs and backcross dogs were from a research colony of inherited ventricular arrhythmias. The control research dogs were purchased.MethodsAction potentials (APs) and pseudo-electrocardiograms (ECG) were recorded from left ventricular (LV) wedge preparations of GSDs and normal dogs. Midmyocardial (Mid) LV cells from GSDs and normal mongrels were isolated by enzymatic digestion. Cells were either field stimulated or voltage clamped and calcium transients were measured by confocal microscopy using the indicator Fluo-3AM. Expression of calcium handling genes was measured by quantitative RT-PCR.ResultsMean calcium transient decay (tau) was not different between affected GSDs and control dogs, but striking cell-to-cell variability for tau was observed within affected GSDs and between affected GSDs and controls (P < 0.0001 each); within-dog variability accounted for 75% of total variability. Calcium sparks and afterdepolarizations occurred in GSD but not control cells. ATP2A2/SERCA2a expression was significantly reduced (P = 0.0063) in affected GSDs and inversely correlated (P = 0.0006) with severity of ventricular arrhythmias.ConclusionsGerman shepherd dogs with inherited ventricular arrhythmias have electrophysiologic abnormalities in calcium cycling associated with reduced ATP2A2/SERCA2a expression. These animals provide a unique opportunity to study calcium remodeling at the genetic and molecular level in familial ventricular arrhythmias.     

Do Thyroid Ultrasonographic Features Change According to Age in Euthyroid Dogs?

The thyroid gland was assessed by ultrasound in healthy euthyroid mixed‐breed medium size dogs in different age groups. The objective was to verify ultrasonographic imaging patterns in these groups, as well as to identify possible changes in imaging features resulting from ageing. Thirty dogs – 10 young (<1 year), 10 adult and 10 elderly – without clinical signs or history of thyroid gland disease with complete blood count and thyroid function tests within the reference values were evaluated. Each thyroid lobe was examined by ultrasound for shape, size, echogenicity and echotexture. The analysis of echogenicity and echotexture was made by histogram. Thyroid volume was estimated by the equation for ellipsoid (length × width × height) π/6. The thyroid volume of the young dogs in this study had a tendency to be higher than in adult dogs (P = 0.068) and older dogs (P = 0.120). The height of the thyroid lobe in the longitudinal plane was significantly higher (P = 0.026) in young dogs compared with the other dogs. The echotexture and echogenicity had no significant differences between groups, but the echogenicity was greater in older dogs. The results point out that ultrasound imaging of the thyroid volume is influenced by age in euthyroid dogs.     

Comparison of the sedative effects of intranasal or intramuscular dexmedetomidine at low doses in healthy dogs: a randomized clinical trial

ObjectiveTo compare the sedative effects of dexmedetomidine administered either intranasally or intramuscularly to healthy dogs.Study designProspective, randomized, blinded, clinical trial.AnimalsA group of 16 client-owned healthy dogs.MethodsDogs were randomly allocated to one of two groups that were administered dexmedetomidine 5 μg kg^–1 via either the intranasal route (IN_Dex), through a mucosal atomization device in one nostril, or the intramuscular route (IM_Dex), into the epaxial muscles. Ease of intranasal administration, sedation score, onset of sedation, cardiopulmonary variables, mechanical nociceptive thresholds (MNTs) and response to venous catheterization were recorded at 0 (baseline), 5, 10, 15, 20, 25, 30, 35, 40 and 45 minutes, following drug administration. Data were compared with the one-way anova, Mann-Whitney U test, and chi-square test, where appropriate.ResultsGroups were not different for age, sex, weight, body condition score or temperament. Sedation scores, MNTs and response to intravenous catheter placement were not different when dexmedetomidine was administered by either route (p = 0.691; p = 0.630 and p = 0.435, respectively). Onset of sedation was not different between groups IN_Dex and IM_Dex reaching a score of 4.2 ± 0.9 and 5.5 ± 1.2 at 9 ± 5 and 8 ± 4 minutes, respectively (p = 0.467). The highest sedation score was achieved at 30 and 35 minutes and sedation scores were 9.7 ± 2.0 and 9.5 ± 2.3 in groups IN_Dex and IM_Dex, respectively (p = 0.799). Respiratory rate was higher in group IN_Dex (p = 0.014), while there were no differences between routes in heart rate (p = 0.275), systolic (p = 0.957), diastolic (p = 0.837) or mean arterial pressure (p = 0.921).Conclusions and clinical relevanceIntranasal administration of dexmedetomidine at 5 μg kg^–1 provides effective sedation in healthy dogs.     

Follow-up of 100 dogs with acute diarrhoea in a primary care practice

This study aimed to examine the aetiology of acute diarrhoea and the relapse rate in 100 client-owned dogs presented to a first-opinion clinic. History, physical examination, faecal testing and owner questionnaire data were collected at initial presentation (T₀) and at either the time of relapse or at a recheck performed within 3 months. All dogs received treatment according to their clinical signs. Of 96 dogs that completed the study, 37 (38.5%) relapsed during the study period, 21 (21.9%) relapsed within 3 months, and 16 others (16.6%) at 3 months to 1 year after initial examination. Dogs that had undergone a change in housing location within 1 month prior to presentation and dogs <1 year old were significantly more likely to have positive parasitological analyses (P = 0.02 and P = 0.001, respectively). Pica was a risk factor for relapse (P = 0.0002).     

Quadricuspid aortic valve and associated abnormalities in the dog: Report of six cases

ObjectivesTo describe the clinical and echocardiographic findings in dogs with quadricuspid aortic valve (QAV).BackgroundQAV is a rare canine congenital heart disease which has been reported only three times in the young dog.Animals, materials and methodsSix dogs (0.3- to 13-year-old) with QAV diagnosed by two-dimensional echocardiography were retrospectively evaluated. Medical records, echocardiograms, and follow-ups were reviewed.ResultsAccording to aortic cusp morphology, QAV was classified as type A (n = 1), type B (n = 4) or type C (n = 1). QAV was associated with at least one other heart disease in all of the dogs including, ventricular septal defect (n = 1), enlarged left coronary ostium (n = 4), degenerative mitral valve disease (MVD, n = 1) and patent ductus arteriosus (PDA, n = 3). Mild to moderate aortic regurgitation was also detected in all dogs by continuous-wave and color-flow Doppler echocardiography. QAV was diagnosed in four asymptomatic dogs referred for evaluation of a heart murmur. The remaining two dogs had QAV and PDA with evidence of mild exercise intolerance and moderately retarded growth. The PDA was surgically corrected in both dogs and at the time of writing, 1–2.5 years after the initial diagnosis, none of the six animals shows evidence of clinical signs.ConclusionQAV is a cause of aortic insufficiency. It may incidentally be found by two-dimensional echocardiography in dogs of various ages in association with other congenital or acquired cardiac abnormalities.     

Evaluation of perfusion index as a noninvasive tool to determine epidural anesthesia effectiveness in dogs

ObjectiveTo evaluate perfusion index (PI) as a noninvasive tool to determine effectiveness and onset of epidural anesthesia in dogs.Study designProspective clinical trial.AnimalsA total of 21 adult dogs, aged 6.5 ± 3 years and weighing 34.9 ± 6.4 kg, undergoing a tibial plateau leveling osteotomy.MethodsDogs were premedicated intramuscularly with acepromazine (0.03 mg kg^–1) and hydromorphone (0.1 mg kg^–1) and anesthetized with intravenous propofol (to effect) and isoflurane in oxygen. A surface transflectance probe was secured to the tail base to monitor PI and a dorsal pedal artery catheter was placed for invasive blood pressure monitoring. A lumbosacral epidural was performed with the dog in sternal recumbency. Dogs were randomly assigned for inclusion of epidural morphine (0.1 mg kg^–1) or morphine (0.1 mg kg^–1) and lidocaine (4 mg kg^–1). PI was recorded following instrumentation of each dog just prior to the epidural (baseline), at 10 minute intervals for 30 minutes, before and after the surgical skin incision and before and after completion of the osteotomy. Physiological variables and end-tidal isoflurane were recorded at the same time points.ResultsThere was no significant difference in PI between the groups at any time point. There was a significant change in end-tidal isoflurane before and after the skin incision in the epidural morphine and epidural morphine–lidocaine groups (p = 0.04, p = 0.05, respectively) and before and after the osteotomy in each group for heart rate (p = 0.001, p = 0.04), diastolic (p = 0.01, p = 0.01) and mean arterial blood pressure (p = 0.03, p = 0.05).Conclusions and clinical relevancePI did not provide an objective means for determining the onset or effectiveness of epidural anesthesia in anesthetized dogs and alternate methods of noninvasive assessment should be investigated.     

Prospective echocardiographic and tissue Doppler screening of a large Sphynx cat population: Reference ranges,heart disease prevalence and genetic aspects

Objectives(1) To investigate heart morphology and function using echocardiography and tissue Doppler imaging (TDI), (2) to determine heart disease prevalence and characteristics, and (3) to assess potential genetic features in a population of Sphynx cats presented for cardiovascular screening.AnimalsA total of 147 echocardiographic examinations, including 33 follow-ups, were performed by trained observers on 114 Sphynx cats of different ages (2.62 ± 1.93 years [0.5–10.0]) from 2004 to 2011.MethodsSphynx cats underwent a physical examination, conventional echocardiography, and, if possible, two-dimensional color TDI.ResultsConventional echocardiographic findings included 75/114 normal (65.8%) and 39/114 (34.2%) abnormal examinations with a diagnosis of either congenital heart diseases (n = 16) or hypertrophic cardiomyopathy (HCM, n = 23). In adult healthy cats, a significant body weight effect was observed for several echocardiographic variables, including end-diastolic left ventricular (LV) free wall (P < 0.01), interventricular septum (P < 0.001), and LV diameter (P < 0.001). Mitral valve dysplasia (MVD) was observed as a single or associated defect in 15/16 cats with congenital heart diseases. A significant increase in HCM prevalence (P < 0.001) was observed according to age. The pedigree analysis of a large family (n = 81) suggested an autosomal dominant mode of inheritance with incomplete penetrance for HCM.ConclusionsBody weight should be taken into account when interpreting values of diastolic myocardial wall thicknesses in Sphynx cats. Additionally, HCM and MVD are two relatively common heart diseases in this feline breed. More pedigree data are required to confirm the inheritance pattern of HCM at the breed level.     

Plasma and platelet serotonin concentrations in healthy dogs and dogs with myxomatous mitral valve disease

ObjectivesSerotonin has been implicated in canine myxomatous mitral valve disease (MMVD); however, the sources of serotonin have not been fully elucidated. This study compared the concentration of serotonin in plasma and platelets of normal healthy small breed dogs with predisposition to MMVD and dogs with naturally occurring MMVD.Animals43 small-breed client-owned dogs with an approximate weight of <10 kg and age of 6 years or above were divided into 2 groups: a healthy control group (n = 20) and a group with echocardiographic evidence of MMVD (n = 23).Methods5 ml samples of blood were collected. Plasma and platelets were separated by centrifugation and assayed for serotonin measured by enzyme linked immunosorbent assay (ELISA).ResultsMedian plasma serotonin concentration was not significantly different (p = 0.3630) between normal healthy dogs (3.7 ng/ml) and dogs with MMVD (4.3 ng/ml). Males had higher plasma serotonin concentration than females (4.7 and 2.9 ng/ml respectively, p = 0.0043). Platelet serotonin concentration was not different between healthy dogs and dogs with MMVD (128.6 ng/10⁹ platelets and 176.6 ng/10⁹ platelets respectively, p = 0.4575). Age, echocardiographic indices and platelet count showed no correlation with plasma or platelet serotonin concentration.ConclusionsCirculating plasma serotonin is unlikely a major source of serotonin signaling in canine MMVD. Platelets could be a source of serotonin in canine MMVD through platelet adhesion to the mitral valve; however, the amount of serotonin stored in platelets of healthy dogs and dogs with MMVD is not different.     

Influence of age on bronchoscopic findings in healthy beagle dogs

The aims of this study were to evaluate the effect of age on bronchoscopic features and bronchoalveolar lavage fluid (BALF) cellularity in dogs. Thirty healthy beagle dogs from three age groups were included: young dogs (10 months to 4.5 years of age; n = 8), middle-aged dogs (5–8 years old; n = 13) and older dogs (>8 years; n = 9). Haematology, thoracic radiography, bronchoscopy and bronchoalveolar lavage were performed; bronchoscopic findings were scored and BALF total and differential cell counts were determined. The total bronchoscopic score was higher in older dogs; these dogs had more irregular bronchial mucosa, more prominent mucosal vessels and bronchiectasis. Younger dogs had a higher percentage of neutrophils in BALF compared with middle-aged and old dogs and a higher percentage of lymphocytes in BALF compared with middle-aged dogs. The results show that age has an effect on bronchoscopic features of airways and the composition of BALF in the dog.