Doppler-derived deformation imaging in unsedated healthy adult dogs

Objectives

To evaluate feasibility, repeatability and reproducibility (R&R) of Doppler-derived deformation imaging (DI) in healthy adult dogs.

Animals, materials and methods

Forty-nine dogs underwent physical examination, ECG, blood pressure measurement and echocardiography. Doppler-derived DI parameters obtained from six selected Regions of Interest (ROI) within the left ventricle (LV) were: strain (S), systolic strain rate (SSR), strain rate E wave (SRE), and strain rate A wave (SRA). The averages of the six ROIs were calculated and labeled avS, avSSR, avSRE, and avSRA. Randomly selected dogs underwent two echocardiographic studies to evaluate intraoperator (n = 14) and interoperator (n = 17) variability.

Results

DI data were obtained in 87.2% of dogs and 77.2% of ROIs. Compared to controls, avSSR was significantly reduced in Doberman Pinchers (DP) and it was increased in dogs <30 kg, compared to dogs >30 kg. The intraoperator Coefficient of Variability (CV) for some ROIs was greater than 15% but for averaged measurements it was ≤ 5.0%. Interoperator CV varied widely but were all <15% for avSSR, avS, and avSRA.

Conclusions

The CV for Doppler-derived DI varied widely. Averaging values from multiple ROIs improved R&R. DI may help elucidate differences in LV mechanics between canine breeds.     

Resistance mechanisms and farm-level distribution of fecal Escherichia coli isolates resistant to extended-spectrum cephalosporins in pigs in Spain

Introduction

Fecal Escherichia coli isolates showing a phenotype of reduced susceptibility or resistance to extended-spectrum cephalosporins are common among pigs in Spain. The aim of this study was to describe the main beta-lactam resistance mechanisms carried by these strains and their distribution at farm-level.

Materials and methods

Twenty-nine E. coli isolates showing reduced susceptibility or resistance to extended-spectrum cephalosporins were collected from a sampling frame of 80 pig farms distributed over 13 Spanish provinces. The survey was carried out at the slaughterhouse level in 2004.

Results

Of the 29 isolates, 21 (72%) met the criteria for a positive phenotypic confirmatory test for extended-spectrum beta-lactamases (ESBL). The following ESBLs were detected: SHV-12 (12 isolates, 41%), CTX-M-1 (three isolates, 10%), CTX-M-9 (three isolates, 10%), and CTX-M-14 (three isolates, 10%). The remaining eight isolates (28%) were phenotypically non-ESBL, with seven of them (24%) showing mutations on the chromosomal ampC gene promoter at positions −42 (C → T), −18 (G → A), −1 (C → T), and +58 (C → T). A multiplex PCR for detection of plasmidic class C beta-lactamases was negative for all isolates.

Conclusion

Different ESBLs and other mechanisms linked to extended-spectrum cephalosporin resistance are widely distributed among fecal E. coli from slaughter pigs in Spain.     

A systematic review-meta-analysis of chilling interventions and a meta-regression of various processing interventions for Salmonella contamination of chicken

Context

The results of individual studies investigating the efficacy of chilling and other processing interventions on Salmonella prevalence or concentration in broiler chicken carcasses are inconsistent or contradictory.

Objective

Determine efficacy of chilling on reducing Salmonella prevalence or concentration on broiler carcasses using systematic review-meta-analysis, and explore sources of heterogeneity among studies investigating various processing interventions through meta-regression.

Data sources

A comprehensive search included electronic search in six databases, manual search of reference lists of topic-related articles, and consultation with five topic experts to assure that all relevant intervention research was identified.

Study inclusion

Primary intervention research, published in English, encompassing control, challenge, cohort, or before-and-after study designs investigating the efficacy of any chilling or other processing interventions on Salmonella prevalence or concentration in broiler chicken carcasses.

Risk of bias assessment and data extraction

Data pertaining to study methodology and reported results, chilling or other processing intervention parameters, populations sampled and outcomes measured were assessed for methodological soundness and extracted by two independent reviewers using pretested checklists.

Results

Random-effects meta-analyses of immersion chilling with chlorine (n = 9 trials), acetic acid (n = 16) and potable water (n = 13) trended towards reductions in the odds or log₁₀ CFU/ml of Salmonella. Significant heterogeneity (P-value ≤ 0.1 and I² > 25%) precluded the reporting of pooled summary effect estimates. Meta-regression of all processing interventions indicated that serotype, disinfectant type and treatment time and pH were significantly associated with studies reporting reductions in concentration while study design, population sampled, study setting, publication date, intervention and disinfectant type, and treatment pH were significantly associated with studies reporting reductions in prevalence. Methodological and reporting flaws were consistently observed in relevant intervention research as well as a lack of studies conducted under commercial conditions and using Salmonella concentration outcomes.

Conclusions

Chilling may be effective at reducing Salmonella concentration and prevalence, but significant heterogeneity precluded reporting of pooled summary effect estimates for many chilling interventions. Investigations into potential sources of heterogeneity among all processing interventions found that the use of other chemical disinfectants, such as organic acids and surfactants might result in larger reductions in Salmonella contamination than more commonly utilized oxidizing agents like chlorine.     

Postnatal autonomic activity in the preterm lamb

Background

Early postnatal abnormalities of autonomic nervous system (ANS) activity, including at baseline and following cardiorespiratory challenge, are involved in apneas-bradycardias of prematurity, apparent life-threatening events of infancy and sudden infant death syndrome. Literature data suggest that baseline ANS activity does not mature normally after premature birth.

Objectives

This study performed in preterm lambs was aimed at assessing ANS maturation at baseline and following laryngeal chemoreflexes (LCR), a group of reflexes triggered by the contact of liquids with the laryngeal mucosa.

Methods

Heart rate variability (HRV) and baroreflex sensitivity (BRs) were measured at baseline and after LCR during polysomnographic recordings performed in five non-sedated lambs born 15 days prematurely. Laryngeal chemoreflexes were induced by distilled water or acid (pH 2) during sleep and wakefulness on postnatal days 7 (D7) and 14 (D14, full-term equivalence).

Results

While the life-threatening cardiorespiratory events of the LCR observed at D7 were no longer present at D14, baseline and post-LCR HRV and BRs indices were significantly lower at D14 compared to D7 (up to p < 0.001). These results suggest that an initial autonomic overactivity was present at D7 and normalized at D14.

Conclusion

The autonomic cardiac and baroreflex control appears to follow a specific evolution in the preterm compared to the full-term newborn lamb, with an important initial autonomic stress, which normalizes at an age equivalent to full-term. Potential relevance of these findings in relation to anomalies of cardiac control in the early postnatal period, such as apneas-bradycardias of prematurity, apparent life-threatening events of infancy and sudden infant death syndrome, awaits further studies.     

Cardiac troponin I and C-reactive protein concentrations in dogs with severe pulmonic stenosis before and after balloon valvuloplasty

Objective

To report cardiac troponin I (cTnI) and C-reactive protein (CRP) concentrations in dogs with severe pulmonic stenosis (PS) before and after balloon valvuloplasty (BV).

Background

Increased morbidity and mortality have been reported with severe PS and histopathologic evidence of myocardial damage is demonstrated with BV. Severity of myocardial injury and inflammation associated with severe PS and BV, as assessed by cTnI and CRP, is unknown.

Animals, materials and methods

Serum cTnI and CRP concentrations were measured in dogs with severe PS (n = 23) and following BV (n = 16).

Results

Baseline cTnI and CRP were elevated in 7/23 (30.4%) and 8/23 (34.8%) dogs. Median cTnI at baseline and post-BV were 0.20 ng/mL (range, 0.20-1.29 ng/mL) and 2.85 ng/mL (range, 0.21-55.40 ng/mL), respectively. Median CRP at baseline and post-BV were 3.40 μg/mL (range, 0-14.70 μg/mL) and 11.70 μg/mL (range, 4.20-120 μg/mL), respectively. Post-BV concentrations were significantly increased compared to baseline for cTnI (p < 0.001) and CRP (p = 0.001).

Conclusions

Serum cTnI and CRP are increased in dogs with severe PS and following BV. Future studies should evaluate whether biomarkers correlate with severity and prognosis of PS or can be used to guide therapy.     

Evaluation of pacing site in dogs with naturally occurring complete heart block

Objective

To compare left ventricular synchronization and systolic performance with transvenous pacing of the right ventricular apex (RVA), left ventricular free wall (LVF) or simultaneous pacing of the RVA and LVF (BiV).

Animals, materials and methods

Seven canine patients with complete heart block. Prospective study evaluating effect of pacing site. Twenty four hours following implantation of transvenous BiV pacing systems, electrocardiograms and echocardiograms were assessed during pacing from the: (1) Right Atrial Appendage/RVA (RAA/RVA), (2) RAA/LVF, and (3) RAA/BiV.

Results

QRS duration was significantly shorter with BiV pacing versus LVF pacing (p < 0.001), or RVA pacing (p < 0.001). Echocardiographic indices of systolic performance fractional shortening (FS), ejection fraction (EF), cardiac output (CO) were significantly higher with BiV pacing than with pacing from the RVA (P = 0.023, 0.006, and 0.002 respectively). Cardiac output, measured by the biplane Simpson's method, was higher with LVF versus RVA pacing (P = 0.036). There was no difference in FS or EF when comparing LVF to RVA pacing. Tissue Doppler measurements of synchronization and systolic performance did not show any difference between pacing mode, but a significantly increased number of segments were seen to contract following aortic valve closure during LVF pacing (P = 0.0268) and RVA pacing (P = 0.0197) as compared to BiV pacing.

Conclusions

Findings suggest that BiV pacing improves cardiac output and systolic performance versus RVA pacing. This improvement however, is not reflected in tissue Doppler indices of synchronization and systolic performance.     

Autoantibodies to recombinant canine proinsulin in canine diabetic patients

Objective

To determine whether dogs with spontaneously-occurring diabetes mellitus demonstrate serological reactivity to proinsulin.

Sample population

Serum samples were collected from 15 newly-diagnosed diabetic, 15 insulin-treated diabetic and 15 non-diabetic control dogs.

Procedures

Canine proinsulin was cloned into a prokaryotic expression vector to generate recombinant poly-histidine-tagged protein in Escherichia coli. A Western blotting assay was developed for detection of proinsulin autoantibodies in canine sera.

Results

Reactivity to canine proinsulin was detected in 3 of 15 control dogs, 8 of 15 newly-diagnosed diabetic dogs and 6 of 15 insulin-treated diabetic patients. Of these reactors, only 1 control dog, 1 newly-diagnosed diabetic dog and 3 insulin-treated diabetic dogs recognised porcine insulin by ELISA, suggesting that the remaining proinsulin reactors might have been recognising proinsulin-specific epitopes.

Conclusions and clinical relevance

This study suggests that proinsulin autoantibodies are present in a proportion of diabetic dogs. Further work is required to refine the assay and clarify the significance of these autoantibodies.     

Effects of mosapride citrate, metoclopramide hydrochloride, lidocaine hydrochloride, and cisapride citrate on equine gastric emptying, small intestinal and caecal motility

Objective

Although extensive work has been done to elucidate the beneficial and unfavorable effects of gastrointestinal prokinetic agents in humans, little is known on the effects of these agents in horses. In this study, we compared the effects of mosapride, metoclopramide, cisapride, and lidocaine on equine gastric emptying, jejunal and caecal motility and evaluated these agents’ adverse drug reactions (ADRs).

Animals

Seven healthy adult Thoroughbreds.

Procedure

Mosapride 1.0 mg/kg and 2.0 mg/kg, metoclopramide 0.2 mg/kg, and cisapride 1.0 mg/kg were dissolved in 100 mL distilled water for oral administration. Lidocaine 1.3 mg/kg was mixed with 500 mL saline for a 30-min intravenous infusion. Oral administration of 100 mL distilled water was used as control. Gastric emptying was evaluated using ¹³CO₂ breath test, and jejunal and caecal motility was assessed by electrointestinography.

Results

The present study demonstrates that mosapride at doses of 1.0 mg/kg and 2.0 mg/kg facilitates gastric emptying in horses. Improved jejunal motility was observed following administration of mosapride (1.0 mg/kg and 2.0 mg/kg), metoclopramide (0.2 mg/kg), and cisapride (1.0 mg/kg). Similarly, improved caecal motility was observed following administration of mosapride (2.0 mg/kg).

Conclusions and clinical relevance

This study shows that among the prokinetic agents studied here, only mosapride (2.0 mg/kg) promotes jejunal and caecal motility in horses. Considering mosapride ADRs profile, it is believed that this compound is useful in the treatment of diseases associated with decreased GI motility, including postoperative ileus.     

Assessment of the diagnostic accuracy of circulating cardiac troponin I concentration to distinguish between cats with cardiac and non-cardiac causes of respiratory distress

Objective

To determine if serum cardiac troponin I (cTnI) concentrations can distinguish cardiac from non-cardiac causes of respiratory distress (RD) in cats.

Animals, materials and methods

53 cats. cTnI concentrations were measured in 30 cats with non-cardiac respiratory distress (RD-NC) and compared to 23 cats with RD due to congestive heart failure (RD + CHF).

Results

The RD + CHF group had higher median cTnI concentration (0.94 ng/ml interquartile range IQR 0.54-4.00, range <0.20 - 90.14) than the RD-NC group (<0.2 ng/ml IQR < 0.2-0.33, range <0.20-41.1, p < 0.001). The area under the curve (AUC) was 0.842 (95% CI 0.728-0.955) for the receiver operator curve (ROC) analysis of the accuracy of cTnI concentrations to discriminate RD + CHF from RD-NC cats. A cut-off of ≥ 0.81 ng/ml discriminated RD + CHF from RD-NC cats with a sensitivity and specificity of 65.2% and 90.0% respectively. However considerable overlap in cTnI concentrations between the 2 groups was identified.

Conclusions

Serum cTnI concentrations were different in RD + CHF compared to RD-NC cats. However the overlap in cTnI concentrations between the 2 groups reduced the clinical efficacy of the assay which therefore should not be used as a stand-alone test but in combination with other diagnostics such as echocardiography and radiography.     

L-Arginine inhibiting pulmonary vascular remodelling is associated with promotion of apoptosis in pulmonary arterioles smooth muscle cells in broilers

Objective

Pulmonary vascular remodelling is one of the important pathological bases of broiler pulmonary hypertension syndrome (PHS). Nitric oxide (NO) has been found to inhibit proliferation and to induce apoptosis in pulmonary artery smooth muscle cells (SMC) in mammals with pulmonary hypertension. The present study was conducted to evaluate the effects of NO precursor l-arginine on pulmonary vascular remodelling in broilers with pulmonary hypertension induced by cold exposure and to examine whether NO-induced apoptosis in pulmonary arteriole SMC is involved in the regulatory mechanisms.

Methods

Two hundred and forty mixed-sex commercial broilers were equally assigned to three groups and reared in normal brooding temperatures before day 14. Starting on day 14 continuing until the end of the experiment, the control group was brooded in normal temperatures whereas the other two groups were subjected to low ambient temperatures with or without l-arginine added to the basal diets. Cumulative PHS mortality and body weight were recorded in each group. Right/total ventricle ratio (RV/TV), plasma NO concentration and pulmonary vascular morphological changes were analyzed. TdT-mediated dUTP-biotin nick-end labeling (TUNEL) assay was used to detect apoptosis in pulmonary arteriole SMC.

Result

l-Arginine, in group A, had no effect on body weights under cold temperature condition. Birds kept in group B had increased PHS mortality, RV/TV ratio, vessel wall area/vessel total area ratios (WA/TA) and mean media thickness in pulmonary arterioles (mMTPA) (P < 0.05). Percentages of apoptotic SMC in pulmonary arterioles in group B were not altered by cold exposure (P > 0.05). Supplemental dietary l-arginine in group A elevated plasma NO level (P < 0.05), reduced PHS mortality (P < 0.05), attenuated pulmonary vascular remodelling and increased the percentages of apoptotic SMC (P < 0.05) when compared with the group B.

Conclusion

Supplemental l-arginine partially inhibited pulmonary vascular remodelling that occurred secondary to increased pulmonary pressure; NO-induced apoptosis in arteriole SMC might contribute to its regulatory effect on pulmonary vascular structural changes.     

Association of Plasma N-Terminal Pro-B-Type Natriuretic Peptide Concentration with Mitral Regurgitation Severity and Outcome in Dogs with Asymptomatic Degenerative Mitral Valve Disease

Background: The clinical outcome of dogs affected by degenerative mitral valve disease (MVD) without overt clinical signs is still poorly defined, and criteria for identification of animals that are at a higher risk of early decompensation have not yet been determined.
Hypothesis: N-terminal pro-B-type natriuretic peptide plasma concentration (NT-proBNP) is correlated with mitral regurgitation (MR) severity and can predict disease progression in dogs with asymptomatic MVD.
Animals: Seventy-two dogs with asymptomatic MVD, with or without heart enlargement (International Small Animal Cardiac Health Council: ISACHC classes 1a and 1b), and a control group of 22 dogs were prospectively recruited.
Methods: Severity of MR was quantitatively assessed from the regurgitation fraction (RF) by the proximal isovelocity surface area method. Consequences of MR were evaluated from measurements of the left atrium/aorta ratio (LA/Ao), fractional shortening (FS), end-diastolic and end-systolic left ventricular volumes indexed to body surface area (EDVI and ESVI). The relevance of these echo-Doppler indices and NT-proBNP for prediction of outcome at 12 months was studied.
Results: A significant correlation was found between NT-proBNP and RF, LA/Ao, FS, and EDVI ( P < .05). NT-proBNP was higher in dogs with MVD (ISACHC classes 1a and 1b) compared with the control group ( P = .025 and < .001, respectively). The difference was not significant when only dogs from ISACHC class 1a with RF < 30% were considered. Lastly, NT-proBNP was higher in dogs that underwent MVD decompensation at 12 months ( P < .05).
Conclusions and Clinical Importance: NT-proBNP is correlated with MVD severity and prognosis in dogs with asymptomatic MVD.     

Plasma N-terminal pro-brain natriuretic peptide concentrations before and after pericardiocentesis in dogs with cardiac tamponade secondary to spontaneous pericardial effusion

Objective

To determine if concentrations of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) are increased in dogs with cardiac tamponade and if there is a significant increase in plasma NT-proBNP after pericardiocentesis.

NT-proBNP, NT-proANP and cTnI concentrations in dogs with pre-capillary pulmonary hypertension

Objectives

To compare [NT-proBNP], [NT-proANP] and [cTnI] between control dogs with respiratory disease without pulmonary hypertension (PH) and dogs with pre-capillary PH, and to assess the accuracy of [NT-proBNP], [NT-proANP], [cTnI] to predict Doppler-derived peak tricuspid regurgitation (TR) gradient.

Animals

20 dogs. 8 control dogs with respiratory disease with no PH and 12 with pre-capillary PH.

Methods

[NT-proBNP], [NT-proANP] and [cTnI] were compared between the 2 groups and simple linear regression analysis was used to predict peak TR gradients from various blood biomarkers.

Results

Median [NT-proBNP] was higher in the dogs with PH (2011 pmol/L, 274–7713 pmol/L) compared to control dogs (744 pmol/L; 531–2710 pmol/L) (p = 0.0339). [NT-proBNP] was associated with peak TR gradient (R² = 0.7851, p = 0.0001). Median [NT-proANP] did not differ between dogs with PH (1747 fmol/L; 894–2884 fmol/L) and control dogs (1209 fmol/L; 976–1389 fmol/L (p = 0.058). [NT-proANP] was not associated with peak TR gradient (R² = 0.2780, p = 0.0781). Median [cTnI] did not differ between dogs with PH (0.2850 ng/mL; 0.19–1.13 ng/mL) and control dogs (0.2 ng/mL; 0.19–0.82 ng/mL, p = 0.3051). Median [TnI] was not associated with peak TR gradient (R² = 0.024, p = 0.6307).

Conclusions

[NT-proBNP] concentration is significantly higher in dogs with pre-capillary PH when compared to dogs with respiratory disease without PH, and [NT-proBNP] may be useful to predict the severity of estimated PH. Elevations in [NT-proBNP] due to pre-capillary PH may complicate the interpretation of [NT-proBNP] elevations in patients presenting with cardiorespiratory abnormalities. [NT-proANP] and [cTnI] were not elevated in dogs with pre-capillary PH.     

Quantification of pulmonary to systemic flow ratio by a Doppler echocardiographic method in the normal dog: Repeatability, reproducibility, and reference ranges

Objective

To determine if the pulmonary to systemic flow ratio (Qp/Qs) could be assessed in healthy awake dogs using Doppler echocardiography.

Background

Qp/Qs could provide reliable information in assessing the severity of intracardiac shunts (ICS) by quantifying pulmonary overcirculation. Qp/Qs has been validated against electromagnetic flowmeter methods in experimental canine models. However, its clinical applicability in awake dogs has never been assessed.

Animals, materials and methods

Six healthy dogs were used to determine the repeatability and reproducibility of the technique (Study 1); Qp/Qs was then prospectively assessed in 50 healthy dogs (Study 2). In both studies Qp/Qs was calculated in awake animals using a standardized Doppler echocardiographic method.

Results

Within- and between-day coefficients of variation for Qp/Qs were <10% (Study 1). For Study 2, a relatively wide range of Qp/Qs was found (reference range = 0.71-1.29; mean ± SD = 1.00 ± 0.15).

Conclusions

Qp/Qs can be assessed with good repeatability and reproducibility in healthy dogs. However, the wide range of Qp/Qs obtained in the healthy population may suggest a limited usefulness of this variable for accurately assessing ICS severity in diseased animals. This needs to be assessed in further prospective and longitudinal studies including a large number of animals with ICS of various grades.     

The T wave in the V10 precordial electrocardiographic lead is negative in healthy Chihuahua dogs

Objectives

The T wave polarity in the V10 precordial electrocardiographic (ECG) lead in Chihuahuas is described as positive in the veterinary literature. The aim of this study was to investigate the polarity of the T wave in the V10 precordial ECG lead in clinically healthy Chihuahuas. Our null hypothesis was that healthy Chihuahuas have a negative T wave in V10.

Animals, materials and methods

In this prospective study, 67 healthy breeder-owned Chihuahuas were used. A physical examination, 10-lead ECG and an echocardiogram were performed on each dog.

Results

No cardio-respiratory abnormalities were revealed in any of the otherwise healthy dogs. Three out of 67 ECGs were of insufficient quality because of baseline artifacts due to movement of the animal. Two other ECGs showed a nearly iso-electric T wave in the V10 lead. The remaining 62 ECGs showed negative T waves in the V10 lead. Right ventricular hypertrophy was excluded with echocardiography in all dogs.

Conclusion

In contrast to previous reports, we found that healthy Chihuahuas have negative T wave in the V10 precordial ECG lead.     

Canine Pancreatic‐Specific Lipase Concentrations in Dogs with Heart Failure and Chronic Mitral Valvular Insufficiency

Background

Chronic mitral valvular insufficiency (CMVI) in dogs is very common and might cause clinical signs of congestion and poor tissue perfusion.

Hypothesis

Poor tissue perfusion from CMVI causes pancreatitis in dogs, as indicated by serum pancreatic lipase concentrations.

Animals

Sixty‐two client‐owned dogs consisting of 40 dogs with different stages of heart failure from CMVI and 22 age‐matched healthy dogs, based on full cardiac exam and routine laboratory tests.

Methods

Prospective, controlled, observational study. Serum canine pancreatic lipase immunoreactivity (cPLI) concentrations were determined by quantitative cPLI test in healthy and CMVI groups.

Results

Serum cPLI concentrations were 54.0 μg/L (IQR: 38.0–78.8 μg/L) in control, 55.0 μg/L (IQR: 38.3–88.8 μg/L) in ISACHC I, 115.0 μg/L (IQR: 45.0–179.0 μg/L) in ISACHC II and 223.0 μg/L (IQR: 119.5–817.5 μg/L) in ISACHC III. Close correlation to serum cPLI concentration was found in the left atrial to aorta (LA/Ao) ratio (r = 0.597; P = .000) and the severity of heart failure (r = 0.530; P = .000).

Conclusions and Clinical Importance

This study found CMVI is associated with pancreatic injury in congestive heart failure caused by CMVI. Therefore, periodic monitoring on cPLI could be useful in monitoring dogs in heart failure.     

Analysis of weight uniformity, content uniformity and 30-day stability in halves and quarters of routinely prescribed cardiovascular medications

Objectives

Congenital and acquired cardiac disorders are frequently diagnosed in small breed dogs and cats. In order to appropriately dose cardiovascular drugs for small patients, fractions of commercially available tablets must be prescribed. The aims of this study were to evaluate weight and content uniformity and 30-day chemical stability in halves and quarters of 11 drug formulations commonly prescribed to treat cardiovascular disorders in small breed dogs and cats.

Animals, materials and methods

Fifteen tablets from 11 drug formulations were obtained within the same lot. Tablets were split by a single operator using a commercially available pill splitter. Whole tablets, halves and quarters were weighed and stored in plastic containers. High-pressure liquid chromatography or liquid chromatography with mass spectrometry were utilized to determine drug content and repeated 30 days later to estimate chemical stability.

Results

Statistically significant weight variability, content non-uniformity and chemical degradation were found for some formulations. Digoxin showed a significant degradation that should be considered in clinical practice.

Conclusions

It appears that pill splitting is overall a relatively reliable practice; however tablets should not be split ahead of time but only immediately prior to intended usage.     

Effects of Maropitant Citrate or Acepromazine on the Incidence of Adverse Events Associated with Hydromorphone Premedication in Dogs

Background

Vomiting is a common complication associated with the use of hydromorphine for pre‐emptive analgesia in dogs. The ideal anti‐emetic protocol for prevention of this complication has not been established.

Hypothesis

Maropitant administered concurrently or before hydromorphone would reduce the incidence of vomiting, signs of nausea, ptyalism, and increased panting compared to administration of acepromazine or a 0.9% saline control.

Animals

Sixty mixed‐breed female dogs scheduled for ovariohysterectomy.

Methods

Randomized, blinded, placebo‐controlled experimental study. Dogs were assigned to 4 experimental groups with 15 dogs per group. All groups received 0.2 mg/kg of hydromorphone IM. Group “Control” received 0.1 mL/kg saline SC 30–45 minutes before hydromorphone, group “Marop1” received 1 mg/kg maropitant SC 30–45 minutes before hydromorphone, group “Ace” received 0.02 mg/kg IM acepromazine 30–45 minutes before hydromorphone, and group “Marop2” received 1 mg/kg SC maropitant concurrently with hydromorphone. A trained and blinded observer documented adverse events from the time hydromorphone was administered until the time dogs were induced for surgery.

Results

Marop1 had significantly less vomiting (0%) compared to Control (87%; P < .01) and Ace (53%; P < .01). Marop2 had significantly less vomiting (27%) compared to Control (P < .01). Marop1 had significantly greater incidence of ptyalism (73%) compared to Ace (P < .01; 20%). Ace showed significantly less panting (33%) compared to Marop2 (93%; P < .01).

Conclusions and Clinical Importance

In healthy dogs, maropitant citrate administered before hydromorphone significantly decreases the incidence of vomiting in dogs but does not improve signs of nausea, ptyalism, or increased panting.     

Twenty-four hour Holter monitoring of unsedated healthy cats in the home environment

Objective

To determine the heart rate, rhythm, number of ventricular premature complexes (VPCs) and atrial premature complexes (APCs) in unsedated cats using Holter monitoring.

Animals, materials and methods

Twenty-three healthy client owned cats were used. Clinical examination, blood pressure measurements, echocardiographic examination and serum biochemical analysis were performed. A lightweight Holter was used in the home environment.

Results

Three-lead electrocardiographic registrations of good quality were obtained from all cats. Normal sinus rhythm was present in all cats. The median heart rate was 165 beats per minute (bpm), range 70-303 bpm. Mean heart rate varied significantly with age and gender. Sinus arrhythmia occurred intermittently in 18 cats (78%). Uncommon ventricular premature complexes occurred in 18 (78%) of the cats. The median number of VPCs per cat was 3 complexes/24 h period, range 0-146. Cats 7-15 years of age had significantly more VPCs than cats 1-6 years of age (median 6 versus 1 per 24 h period, p = 0.04). A single APC occurred in one cat (4%).

Conclusions

Cats commonly have intermittent sinus arrhythmia. Many healthy cats have rare single VPCs per 24 h period. Old cats have significantly more VPCs than young cats. The heart rate varies significantly with age and gender.     

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.