Noninvasive transthoracic temporary cardiac pacing in dogs

Temporary cardiac pacing is used in the emergency treatment of life-threatening bradyarrhythmias and for the support of heart rate and blood pressure of patients with sick sinus syndrome or high-grade atrioventricular (AV) block undergoing general anesthesia, typically for permanent pacemaker implantation. We retrospectively evaluated the safety and efficacy of a noninvasive transthoracic external cardiac pacing system in 42 dogs treated for bradyarrhythmias. Optimal placement of the patch electrodes on the skin of the thorax was initially established on 2 anesthetized normal dogs. The optimal electrode placement was determined to be on the right and left hemithoraces, directly over the heart. Afterward, by means of this electrode placement all 42 dogs treated for bradyarrhythmias in this study were successfully paced with the noninvasive transthoracic system. Dogs ranged in age from 1 to 15 years and weighed between 3.2 and 40 kg. Miniature Schnauzers, German Shepherds, and mixed breeds were most common in the study population. Indications for noninvasive transthoracic pacing included emergency treatment of hemodynamically unstable 3rd-degree AV block (2 dogs): support of heart rate during general anesthesia for permanent pacemaker implantation or lead-wire adjustment (38 dogs): and support of heart rate during general anesthesia for ophthalmologic surgery in dogs with sick sinus syndrome (2 dogs). Complications included pain and skeletal muscle stimulation, which required general anesthesia. We conclude that the noninvasive transthoracic pacing system evaluated is satisfactory for clinical veterinary use.     

The prognostic significance of minimal residual disease in the early phases of chemotherapy in dogs with high-grade B-cell lymphoma

The prognostic significance of minimal residual disease (MRD) in the early phases of chemotherapy was examined in 36 dogs with multicentric high-grade B-cell lymphoma. Sequences of immunoglobulin heavy chain (IgH) gene fragments from lymphoma cells were amplified and used to design allele-specific primers and probes for real-time PCR. The dogs were treated with a 6-month modified version of the University of Wisconsin–Madison chemotherapy protocol (UW-25) and evaluated for the MRD level at weeks 6 and 11 of UW-25.Of the 31 dogs that remained on the protocol at week 11, 14 were found to be MRD negative (<10 tumour cells/10⁵ peripheral blood mononuclear cells [PBMCs]), whereas the other 17 were MRD positive (?10 tumour cells/10⁵ PBMCs). The progression-free survival of the dogs with MRD-negative status at week 11 (median, 337 days) was significantly longer than that of the MRD-positive dogs at the same time point (median, 196 days) (P = 0.0002). These results indicate the clinical significance of MRD as a prognostic marker in the early phase of chemotherapy.     

Psoas compartment and sacral plexus block via electrostimulation for pelvic limb amputation in dogs

Objective

To assess the efficacy of psoas compartment and sacral plexus block for pelvic limb amputation in dogs.

Arrhythmogenic right ventricular cardiomyopathy in Boxer dogs is associated with calstabin2 deficiency

ObjectiveTo examine the presence and effect of calstabin2-deficiency in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC).AnimalsThirteen Boxer dogs with ARVC.Materials and methodsTissue samples were collected for histopathology, oligonucleotide microarray, PCR, immunoelectrophoresis, ryanodine channel immunoprecipitation and single-channel recordings, and calstabin2 DNA sequencing.ResultsIn cardiomyopathic Boxer dogs, myocardial calstabin2 mRNA and protein were significantly decreased as compared to healthy control dogs (calstabin2 protein normalized to tetrameric cardiac ryanodine receptor (RyR2) complex: affected, 0.51 ± 0.04; control, 3.81 ± 0.22; P < 0.0001). Calstabin2 deficiency in diseased dog hearts was associated with a significantly increased open probability of single RyR2 channels indicating intracellular Ca²⁺ leak. PCR-based sequencing of the promoter, exonic and splice site regions of the canine calstabin2 gene did not identify any causative mutations.ConclusionsCalstabin2 deficiency is a potential mechanism of Ca²⁺ leak-induced ventricular arrhythmias and heart disease in Boxer dogs with ARVC.     

The use of an acoustic device to identify the epidural space in cattle

Twelve healthy cattle (weighing 188–835 kg) were placed in stocks and sedated with xylazine. Caudal epidural puncture was performed using an acoustic device that indicated a decrease in resistance with a change in pitch. Lidocaine was injected to verify correct needle placement by assessing needle prick stimuli applied on the left and right side of the tail root and the perineal region, and the loss of tail and anal sphincter tone. Pressure measurements were recorded during penetration of the different tissue layers and in the epidural space. A clear and sudden decrease in the pitch of the acoustic signal was audible in all 12 cattle. All cows showed clinical effects indicating successful epidural anaesthesia. The pressure in the epidural space after puncture was ?19 ± 10 mm Hg. The device may be of assistance in identifying the epidural space in cattle.     

Computed tomographic morphology and clinical features of extrahepatic portosystemic shunts in 172 dogs in Japan

Canine extrahepatic congenital portosystemic shunts (EH-cPSS) are classified into several anatomical types, depending on the origin and termination of the shunt vessel. The aim of this retrospective study was to determine the proportion and clinical features of each anatomical shunt type in a population of dogs presented to a veterinary teaching hospital in Japan. Dogs diagnosed with EH-cPSS using computed tomographic (CT) portography were included (n = 172) and shunts were classified based on previous reports. Clinical data were collected from case records and analysed statistically. The most common anatomical type was the spleno-phrenic shunt (n = 64), followed by the spleno-azygos (n = 38), right gastric-caval (n = 29), spleno-caval (n = 21), right gastric-caval with caudal loop (n = 9), right gastric-phrenic (n = 6), colono-caval (n = 3), spleno-phrenic and azygos (n = 1), and porto-caval (n = 1) shunts. Spleno-phrenic and spleno-azygos shunts were diagnosed more frequently in older dogs than right gastric-caval and spleno-caval shunts (P < 0.05). The portal vein/aortic (PV/Ao) ratio was significantly larger in dogs with spleno-phrenic shunts than in dogs with spleno-azygos, right gastric-caval or spleno-caval shunts (P < 0.05). The PV/Ao ratio was significantly larger in dogs with spleno-azygos shunts than in dogs with right gastric-caval shunts. Dogs with spleno-phrenic shunts had significantly lower serum alkaline phosphatase activities than those with right gastric-caval or spleno-caval shunts. Dogs with spleno-phrenic shunts had significantly lower fasting ammonia concentrations than those with spleno-caval shunts.     

Increased chymase-like activity in a dog with congenital pulmonic stenosis

ObjectivesThis study was intended to compare the tissue chymase-like activity and angiotensin converting enzyme (ACE) activity in the right and left ventricles of a dog with congenital pulmonic stenosis (PS), with normal dogs, and to discuss the potential clinical implications of these findings.Animals, materials and methodsStudy subjects included a one-year-old Beagle dog with spontaneous PS and six clinically normal Beagles. Chymase-like and ACE activities were determined in all hearts by high pressure liquid chromatography.ResultsIn the PS dog right ventricular (RV) chymase-like activity (49.79 nmol/min/g tissue) and left ventricular (LV) chymase-like activity (36.85 nmol/min/g tissue) were elevated vs normal Beagle dogs (mean ± standard deviation, RV: 20.17 ± 5.24 nmol/min/g, LV: 19.03 ± 3.27 nmol/min/g).ConclusionsActivation of the tissue RAA system was detected in a dog with congenital PS. This interesting finding should be pursued with further studies to validate this result, and to explore whether pharmacological blockade of chymase, or the angiotensin II receptor, represents a useful strategy to prevent myocardial remodeling in this condition.     

Feasibility and repeatability of thermal quantitative sensory testing in normal dogs and dogs with hind limb osteoarthritis-associated pain

The objectives of this study were to determine whether thermal quantitative sensory testing (QST) can be performed in client-owned dogs, is repeatable and whether QST differs between normal dogs and dogs with hind limb osteoarthritis (OA). This clinical, prospective, observational study used clinically normal dogs (n = 23) and dogs with OA-associated hind limb pain (n = 9). Thermal QST was performed in standing dogs using a high-powered light source delivered by a previously validated system. Dogs were tested on two occasions, 2 weeks apart. Five tests were performed on each hind limb at each time point. Repeated measures analysis of variance was used to evaluate the effects of leg, time point and OA/normal status on thermal threshold latencies (TTL). Additionally, paired t tests were used to compare the TTL of left and right limbs within groups and between time points.Thermal thresholds were successfully measured in 32 client-owned dogs without prior training. TTL were significantly different between normal and OA dogs (P = 0.012). There was no difference between limbs (P = 0.744) or time periods (P = 0.572), when analyzed by repeated measures analysis of variance, and no interactions between group and limb, visit and limb, or visit and group. In conclusion, thermal thresholds can be measured in client owned dogs with no prior training and are repeatable from week to week. Further data are required to determine if OA results in thermal hypoalgesia as measured at the distal hind limb and whether this is an indication of central sensitization.     

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.     

Radial strain and strain rate by two-dimensional speckle tracking echocardiography and the tissue velocity based technique in the dog

ObjectivesTwo-dimensional (2D) speckle tracking echocardiography (STE) is a new angle-independent ultrasound technique based on tracking of speckles within the myocardium on 2D grayscale images. The aims of this prospective study were as follows: (1) to assess the variability of left ventricular peak systolic radial strain (St) and strain rate (SR) in awake dogs using STE (Protocol 1); and (2) to quantify these variables in a healthy canine population and compare them with tissue Doppler imaging (TDI)-based St and SR values (Protocol 2).BackgroundSt and SR may be assessed using TDI, which is limited by angle dependency.Animals, materials and methodsThirty-six STE examinations were performed on 6 healthy dogs for Protocol 1 and 37 healthy dogs were recruited for Protocol 2. In both studies, STE measurements were obtained offline from the right parasternal short-axis view by the same trained observer using automatic frame-to-frame tracking of grayscale speckle patterns.ResultsAll within- and between-day coefficients of variation were <10% (Protocol 1). In Protocol 2, St (46.7 ± 12.2%) and SR (2.7 ± 0.6 s⁻¹) measured by STE were correlated with heart rate (p < 0.01), but not with the ratio of early mitral inflow velocity to early mitral annular velocity. There was a good correlation between STE and TDI for both St and SR values (p < 0.001).ConclusionsSTE is a repeatable and reproducible non-Doppler method for assessing radial St and SR. The combination of these indices with conventional echo-Doppler variables could provide a new approach for accurately quantifying canine systolic function.     

Nerve Stimulator–Guided Sciatic-Femoral Block in Pet Rabbits (Oryctolagus cuniculus) Undergoing Hind Limb Surgery: A Case Series

This article describes the clinical applicability of a nerve stimulator–guided technique, previously described in dogs, to block the sciatic and the femoral nerves in 4 pet rabbits (Oryctolagus cuniculus) undergoing hind limb surgeries. Preanesthetic intramuscular doses of medetomidine (0.08 mg/kg), ketamine (15 mg/kg), and buprenorphine (0.03 mg/kg) were administered to the rabbit patients. The rabbits were intubated and general anesthesia was maintained using isoflurane in oxygen. The sciatic-femoral nerve block was performed with 2% lidocaine at a volume of 0.05 mL/kg/nerve. Sciatic-femoral block was feasible in rabbits, and the motoric responses following electrical stimulation of both nerves were consistent with those reported in dogs after successful nerve location. Iatrogenic complications, namely nerve damage and local anesthetic toxicity, did not occur. Based on these results, the authors conclude that the sciatic-femoral nerve block described in dogs can be safely performed in rabbits. Clinical trials are required to assess the analgesic efficacy of the combined sciatic-femoral nerve block in rabbits as a part of multimodal pain management.     

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.     

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.     

Noninvasive stroke volume variation using electrical velocimetry for predicting fluid responsiveness in dogs undergoing cardiac surgery

Objective

To evaluate the ability of a noninvasive cardiac output monitoring system with electrical velocimetry (EV) for predicting fluid responsiveness in dogs undergoing cardiac surgery.

Effects of constant rate infusions of dexmedetomidine or MK-467 on the minimum alveolar concentration of sevoflurane in dogs

Objective

To determine the effects of low and high dose infusions of dexmedetomidine and a peripheral α₂-adrenoceptor antagonist, MK-467, on sevoflurane minimum alveolar concentration (MAC) in dogs.

Alfaxalone alone or combined with midazolam or ketamine in dogs: intubation dose and select physiologic effects

Objective

To determine the intubation dose and select physiologic effects of alfaxalone alone or in combination with midazolam or ketamine in dogs.

Antinociceptive efficacy and plasma concentrations of transdermal buprenorphine in dogs

To assess the antinociceptive efficacy of transdermal (TD) buprenorphine (B) in dogs, a prospective, positive-controlled experimental study was performed in 10 healthy Beagles. In an open label crossover design, the dogs initially received intravenous B (IVB, 0.02 mg kg^?1) as a positive control, followed by TDB (52.5 μg h^?1) 4 months later. Blood was collected at regular intervals for determination of the plasma concentrations of B ([B]) and its metabolite norbuprenorphine. The antinociceptive efficacy was assessed using thermal and mechanical models of nociception. The peak concentration [B] was 1.54 ng mL^?1 (±1.98) 60 h after TDB application, although three dogs had no measurable [B] after TDB. Maximum thermal threshold (TT) was 52.6 °C (±0.48) at 1 h after IVB administration and 51.63 °C (±1.01) 72 h after TDB application. The significant increase in TT indicated that effective antinociception was achieved beyond 36 h after the application of TDB, lasting until patch removal. There was hysteresis between [B] and the antinociceptive effect.     

Kinematic analysis in healthy and hip-dysplastic German Shepherd dogs

This study investigated kinematic patterns in clinically normal German Shepherd dogs (GSDs) compared to those with hip dysplasia and with no clinical signs of lameness. Two groups of GSDs, including 10 clinically healthy dogs (G1) and 10 with hip dysplasia (G2), were trotted on a treadmill at a constant speed. Kinematic data were collected by a 3-camera system and analysed by a motion-analysis program. Flexion and extension joint angles and angular velocities were determined for the shoulder, elbow, carpal, hip, stifle, and tarsal joints.Within each group, the differences between the right and left limbs in all kinematic variables were not significant. Minimum angle, angular displacement and minimum angular velocity did not differ between groups. Significant differences were observed in the maximum angular velocity and maximum angle of the hip joint (dysplastic > healthy), and in the maximum angular velocity of the carpal joint (healthy > dysplastic). It was concluded that, when trotting on a treadmill, dysplastic dogs with no signs of lameness may present joint kinematic alterations in the hind as well as the forelimbs.     

Comparative speed of efficacy against Ctenocephalides felis of two oral treatments for dogs containing either afoxolaner or fluralaner

A study was designed to compare the efficacy of NexGard^® and Bravecto™, 2 recently introduced oral ectoparasiticides containing isoxazolines, against fleas (Ctenocephalides felis) on dogs. Twenty-four healthy dogs, weighing 9.2 kg to 28.6 kg, were included in this parallel group design, randomized, and controlled efficacy study. On Day −1, the 24 dogs were allocated to 3 study groups: untreated control; Nexgard^® treated and Bravecto™ treated. The treatments were administered on Days 0, 28 and 56 for Nexgard^® (labelled for monthly administration), and once on Day 0 for Bravecto™ (labelled for a 12 week use). Flea infestations were performed weekly with 100 adult unfed C. felis on each dog from Days 42 to 84. Fleas were counted and re-applied at 6 and 12 h post-infestation and removed and counted 24 h post-infestation. The arithmetic mean flea count for the untreated group ranged from 62.9 to 77.6 at 24 h post-infestation, indicating vigorous flea challenges on all assessment days. Both the Nexgard^® and Bravecto™ treated groups had statistically significantly (p < 0.05) less fleas compared to the untreated group on all assessment time points and days. Significantly fewer fleas were recorded for NexGard^® treated dogs compared to Bravecto™ treated dogs at 6 h post-infestation on Day 56, 63, 70, 77 and 84 and at 12 h post-infestation on Days 70 and 84. No statistically significant (p < 0.05) differences were recorded between the treated groups at 24 h post-infestation. Efficacies recorded 6 h post-infestation for Nexgard^® ranged from 62.8% (Day 49) to 97.3% (Day 56), and efficacies ranged from 94.1% (Day 49) to 100% (Days 42, 56, 70 and 84) at 12 h post-infestation. Efficacies recorded for Bravecto™ ranged from 45.1% (Day 84) to 97.8% (Day 42) at 6 h post-infestation, and from 64.7% (Day 84) to 100% (Days 42 and 56) at 12 h post-infestation. Efficacies observed at 24 h were 100% for both products during the study except 99.6% on Day 84 for Bravecto™.