Transient P' waves in a hyperkalemic cat: artifact or dissociation?

A 15-year-old Sphynx cat was referred for cervical ventroflexion, ataxia, and lethargy associated with hypokalemia. After administration of supplemental potassium, the cat became severely hyperkalemic. Transient P' (vs. pseudo P' waves) were detected on the electrocardiogram. Over the course of hospitalization, the cat's potassium normalized, and the abnormal P' waves did not recur. These images are presented to highlight the differential diagnoses for this type of electrocardiogram. Diagnostic considerations included complete or transient atrial dissociation (as a rare consequence of hyperkalemia), atrial parasystole, and various electrocardiographic artifacts. Definitive diagnosis of atrial dissociation requires an electrophysiologic study or echocardiographic documentation of two independent atrial rhythms with associated mechanical activity, but these were unavailable in this case.

Effects of two-dose intravenous administration of furosemide on clinical variables, electrocardiographic indices and serum electrolytes in dromedary calves.

The intravenous (IV) usage of diuretic agents such as furosemide may cause changes in clinical signs, electrocardiographic (ECG) indices and serum electrolytes (sodium, potassium, chloride, calcium, phosphorus and magnesium) concentrations in dromedary calves. The purpose of this study was to evaluate the clinical, ECG and biochemical effects of two-dose IV administration of furosemide in dromedary calves. A total of 21 clinically healthy male dromedary calves with the age of 5 (± 1) months and weight of 95 (± 5) kg were studied. The animals were randomly divided into three groups of control (normal saline), low-dose furosemide (2.5 mg/kg) and high-dose furosemide (5 mg/kg). Two IV injections with 12-hr intervals were administered in all animals. The clinical and ECG parameters were measured at 0 (baseline), 2 (T2), 24 (T24) and 48 (T48) hours after drug administration. Serum concentrations of electrolytes were measured at T0, T24 and T48 hr. The results of this study showed no changes in clinical parameters (heart rate, rectal temperature, respiratory rate and Unruminal motility), ECG indices and also no significant changes in serum electrolytes levels. Under conditions with free access to fresh water, two-dose IV injection of furosemide (2.5 and 5 mg/kg) could be administered in healthy dromedary calves.

Pulmonary vein firing initiating atrial fibrillation in the horse: Oversized dimensions but similar mechanisms.

Atrial fibrillation is triggered by the pulmonary veins in humans. Although atrial fibrillation is known to occur in other species, the mechanisms of disease in these are not known. Here we present evidence for pulmonary vein triggers in the horse, where 3D HD Grid mapping was undertaken in the conscious state in the absence of fluoroscopy.

Flavonoid bioactive compounds of hawthorn extract can promote growth, regulate electrocardiogram waves, and improve cardiac parameters of pulmonary hypertensive chickens.

The effect of orally administered hawthorn flavonoid extract (HFE) on growth, electrocardiographic waves, and cardiac parameters of pulmonary hypertensive chickens reared at high altitude (2,100 m above sea level) was examined. A total of 225 one-day-old, mixed broiler chicks (3 treatments with 5 replicates and 15 chicks per each, totally 75 birds/treatment) were assigned to 3 experimental groups: 0, 0.1, and 0.2 ml of HFE per 1 L of drinking water. Birds were administered the drinking water HFE treatments for 42 D. At an age of 28 and 42 D, electrocardiograms were undertaken and cardiac parameters such as the RV:TV, RV:BW, and TV:BW, and indicators of PHS on selected birds were measured. The final BW of chickens receiving the HFE at 0.2 ml/L was greater (2,579 ± 64 g) than that of birds receiving 0.1 ml/L (2,497 ± 62 g) and 0 ml/L (2,323 ± 57 g). Therefore, no supplemented group had a lower final BW than others (P < 0.05). Amplitudes of S and T waves in 0.1- and 0.2-ml/L HFE consumed groups at 28 and 42 D of age decreased compared with that in the control group (P < 0.05). The HFE reduced the heart weight and RV:TV, RV:BW, and TV:BW ratios when supplemented in drinking water at 0.1 and 0.2 mL/L compared with 0 mL/L (P < 0.05). In conclusion, supplementation of HFE in drinking water can reduce the PHS and incidence of cardiac disorders. Owing to the positive effect of HFE on cardiac parameters that mediated through flavonoids bioactive compounds, this product can be used to prevent complications of pulmonary hypertension and disarray of electrocardiographic waves in broiler chickens reared at high altitude.

Investigation of ventricular pre-excitation electrocardiographic pattern in two horses: clinical presentation and potential causes.

Two horses referred to the Unitat Equina, Fundació Hospital Clínic Veterinari, Universitat Autònoma de Barcelona, for unrelated clinical problems, and with no previous history of cardiac disease exhibited an intermittent ventricular pre-excitation electrocardiographic pattern during hospitalization. Both animals showed decreased plasma total and ionized magnesium concentrations, but no other relevant electrolyte disturbances were detected. Altered interventricular septal motion associated with ventricular pre-excitation beats (VPBs) was detected on M-mode echocardiography in both horses. The likely localization of an accessory pathway (AP) was identified in case 2 using pulsed-wave tissue Doppler imaging in the left anterior paraseptal location. Decreased frequency of the VPB was observed with long-term magnesium supplementation and restoration of plasma magnesium concentrations. The presence of ventricular pre-excitation electrocardiographic pattern was attributed to higher sensitivity of the AP to hypomagnesemia in both cases.

Influence of long-term oral application of quinolones on the ECG curve in dogs.

The aim of the study was to analyse the influence of enrofloxacin and pradofloxacin administered orally for 14 days on the ECG in dogs. The ECG was performed before and after a 14 day period of quinolone administration. There was an increase in the QTc and the TpTe interval in the group treated with quinolones. QTc was prolonged by 24 ms (p=0.001). The TpTe interval was shortened, on average, by 6.55 ms (p=0.048). In the group treated with enrofloxacin, QTc was prolonged by 16.27 ms (p=0.006) and the TpTe interval was shortened by 9.64 ms (p=0.050), the TpTe/QT index was reduced by 0.034 (p=0.050) on average. In dogs treated with pradofloxacin, QTc was prolonged by 21.55 ms (p=0.012) on average. The results suggest that a prolonged administration of quinolones can increase the risk of arrhythmias. Furthermore, different generations of these drugs increase this risk to various degrees. The study proved that second generation quinolones, such as enrofloxacin, significantly change the phase of depolarization and repolarization of the ventricles, at the same time increasing the risk of ventricular arrythmia. Pradofloxacin does not change the TpTe and TpTe/QT values, so it is safer in use.

Clinical and histopathological features of myocarditis in dogs with visceral leishmaniasis / Aspectos clínicos e histopatológicos da miocardite em cães com leishmaniose visceral

Visceral leishmaniasis (VL) is a cosmopolitan parasitic zoonosis that can promote myocarditis and heart rate changes in canine and human hosts. Thus, histopathological aspects of the myocardium and clinical, hematological, biochemical, radiological and electrocardiographic data were evaluated in a group of 36 dogs naturally infected with VL (VLG) and compared to data from 15 non-infected dogs (CG=Control Group). A prevalence of asymptomatic dogs was present in the CG (100%) and polysymptomatic dogs in the VLG (66%). In addition, two dogs in the VLG demonstrated systolic murmurs in the mitral valve region: one with a II/VI intensity and the other with a III/VI intensity. The mean values of RBC, hemoglobin and hematocrit were lower in dogs in VLG and were associated with higher values of total protein, total leukocytes, neutrophils, creatine kinase overall (CK) and the CK-MB fraction (CK-MB). The absence of radiographic changes was accompanied by a predominance of respiratory sinus arrhythmia associated with episodes of migratory pacemaker and sinus arrest in dogs in VLG (75%), sinus rhythm in dogs in CG (60%) and decreased P wave amplitude in VLG electrocardiography. Mononuclear cell infiltration was detected in the myocardium of 77,8% of dogs in GVL and classified primarily as mild multifocal lymphohistioplasmacytic. Amastigotes were detected in only one dog, which did not allow the association between myocarditis and parasitism, although the myocardial lesions that were found constitute irrefutable evidence of myocarditis in the VLG dogs, accompanied by lenient electrocardiographic changes compared to CG.

A leishmaniose visceral (LV) é uma zoonose parasitária cosmopolita capaz de promover miocardite e alterações no ritmo cardíaco em cães e seres humanos. Dessa forma, os aspectos clínicos, hematimétricos, bioquímicos, radiográficos, eletrocardiográficos e histopatológicos do miocárdio foram avaliados em 36 cães naturalmente infectados com LV (GLV) e comparados a 15 cães não infectados (GC). Houve predomínio de cães assintomáticos no GC (100%) e polissintomáticos no GLV (66%). Dois cães do GLV apresentaram sopro sistólico de intensidade II/VI e III/VI, em região de foco mitral. Os valores médios de hemácia, hemoglobina e hematócrito foram inferiores nos cães do GLV, associados a maiores valores de proteína total, leucócitos totais, neutrófilos, creatinina quinase total (CK) e fração MB (CK-MB). Ausência de alterações radiográficas foi acompanhada de predomínio de arritmia sinusal respiratória associada a episódios de marcapasso migratório e sinus arrest nos cães do GLV (75%), ritmo sinusal nos cães do GC (60%) e diminuição da amplitude da onda P no GLV à eletrocardiografia. Infiltrado inflamatório mononuclear foi detectado no miocárdio de 77,8% dos cães do GLV, classificados, em sua maioria, como linfoistioplasmocitário multifocal leve. A forma amastigota foi detectada em apenas um cão, não permitindo a associação entre a miocardite e a parasitose, ainda que as lesões miocárdicas encontradas constituam prova irrefutável da miocardite nos cães do GLV, acompanhadas por alterações eletrocardiográficas brandas em comparação ao GC.

The disruption of mitochondrial metabolism and ion homeostasis in chicken hearts exposed to manganese.

Exposure to high levels of manganese (Mn) can result in cardiotoxicity in animals. However, little is known about the effect of excess Mn on poultry hearts. The aim of this study was to investigate the effect of dietary Mn on chicken cardiac injuries and the possible mechanisms of this process. In the present study, 400 fifty-day-old Hy-line brown cocks were randomly divided into four groups, and were fed either a commercial diet (containing 100mg/kg Mn) or a Mn-supplemented diet containing 600mg/kg, 900mg/kg, or 1800mg/kg Mn for 30, 60 or 90 days, respectively. Next, we examined several biomarkers of cardiac injury, including biochemical blood serum analyses, electrocardiogram assays, histological analyses, ultra-structural assays and apoptosis assays. To investigate the possible mechanisms of Mn-induced cardiotoxicity, we examined the effect of MnCl(2) on mitochondrial function and metal ion homeostasis. We found that subchronic MnCl(2) exposure induced damage in chicken hearts. Further investigations indicated that possible mechanisms for Mn-induced chicken cardiac injury included the disruption of mitochondrial metabolism and the alteration of ion homeostasis.

Comparative evaluation of halothane anaesthesia in medetomidine-butorphanol and midazolam-butorphanol premedicated water buffaloes (Bubalus bubalis).

Six clinically healthy male water buffaloes (Bubalus bubalis) 2-3 years of age and weighing 290-325 kg were used for 2 different treatments (H1 and H2). The animals of group H1 were premedicated with medetomidine (2.5 g/kg,i.v.) and butorphanol (0.05 mg/kg, i.v.), while in group H2 midazolam (0.25 mg/kg) and butorphanol (0.05 mg/kg) were used intravenously. Induction of anaesthesia was achieved by 5% thiopental sodium in H1 (3.85 +/- 0.63 mg/kg) and H2 (6.96 +/- 0.45 mg/kg) groups. The anaesthesia was maintained with halothane in 100 % oxygen through a large animal anaesthetic machine. Better analgesia and sedation with a significantly lower dose of thiopental for induction and significantly higher values of sternal recumbency time and standing time were recorded in group H1 than in group H2, whereas no significant (P > 0.05) difference for the halothane concentration was observed between groups H1 and H2. Significant decrease in heart rate was observed in group H1 whereas it significantly increased in group H2. In both groups, RR decreased during the preanaesthetic period, which increased significantly (P < 0.01) after halothane administration. In both groups a significant (P < 0.01) fallin RT was recorded from 20 min to the end of observation period. A significant (P < 0.05) fall in MAP was observed in group H1 from 15 min until the end, while in group H2 MAP increased nonsignificantly (P > 0.05) after premedication and a significant (P < 0.05) occurredafter thiopental administration. In both groups a significant (P < 0.01) increase in CVP and a significant (P < 0.01) decrease in SpO2 were observed after premedication which persisted up to 120 min. ECG changes included significant (P < 0.01) decrease and increase in QRS amplitudes in groups H1 and H2 respectively, a significant (P < 0.05) increase in PR interval was recorded at 15 min in group H1, a significant (P < 0.05) decrease in PR interval in group H2, a significant (P < 0.05) decrease in T wave amplitude in group H1, and a significant (P < 0.01) increase in duration of T wave in group H1 . It is concluded that both combinations can be used safely in buffaloes for surgery of 2 h duration but better sedation, analgesia and muscular relaxation and more dose sparing effect on anaesthetics and shorter recovery times were observed in group H1.

Evaluation of an algorithm for highly automated measurements of QT interval.

INTRODUCTION: Noise, artifact, and labile morphology of ECGs collected from freely moving animals in safety pharmacology studies render accurate measurements of QT interval challenging. Consequently, a high percentage of beats are uninterpretable and results provided by currently available analysis algorithms often require extensive manual review to correct errors. Performance of a novel algorithm, Multi-Domain Signal Processing™ (MDSP), is evaluated as a means of removing noise (denoising) without distorting morphology and for obtaining accurate beat-to-beat QT measurements. METHODS: Performance was evaluated using controlled experiments and an observational evaluation as follows: a) a clean ECG strip was intentionally corrupted with varying levels of noise to provide recordings of known signal-to-noise ratio (SNR). SNR and fidelity were compared pre- and post-MDSP denoising, b) beat-to-beat QT of a noisy ECG was measured manually pre- and post-MDSP denoising and automatically by MDSP, c) beat-to-beat QT of a clean ECG was measured manually and automatically using MDSP, and d) beat-to-beat QT was computed for 3 freely moving non-human primates (NHP) pre- and post-torsadogen administration and the impact of averaging on QTSD, QT/RR dynamics and relationship was evaluated. RESULTS: MDSP reduced noise amplitude by up to 85% while preserving signal morphology. Mean QTs for manual and automatic measurements on a noisy ECG were within 2±15ms. MDSP-denoising prior to manual QT measurements resulted in a 22% decrease in QTSD compared to measurements obtained without denoising. Average QT standard deviation of the mean (QTSD) for automatic MDSP-derived measurements for 3 freely moving subjects was 7ms with 2.5% of beats automatically excluded due to noise. DISCUSSION: This work demonstrates that the MDSP algorithm shows promise as a tool for providing accurate automatic beat-to-beat measurements of QT interval from NHP in safety pharmacology studies. A methodology is presented for characterizing the impact of noise on algorithm performance.

Cardiovascular and respiratory safety pharmacology in Göttingen minipigs: Pharmacological characterization.

INTRODUCTION: Similarities between pigs and humans support the relevance of Göttingen minipigs for regulatory safety pharmacology. The minipig is the species of choice for cardiovascular safety pharmacology when pivotal repeat toxicology studies are conducted in this species. METHODS: 4 male Göttingen minipigs with cardiovascular telemetry transmitters received intravenous saline, esmolol (0.5, 1, 2, 4 and 8mg/kg), medetomidine (0.04mg/kg), remifentanil (0.5, 1, 2, 4, 8 and 16µg/kg) and dopamine (2, 8, 10, 20, 30 and 50µg/kg/min) and oral sotalol (3 and 10mg/kg). Respiratory monitoring was conducted in 3 male and 3 female Göttingen minipigs receiving intravenous saline and methacholine (0, 3.4, 13.5 and 68µg/kg). RESULTS: Heart rate (HR) corrected QT was optimal with a method based on analysis of covariance (QTca) followed by Fridericia's standard formula. Esmolol induced a decrease in HR. Medetomidine was associated with an initial hypertension with bradycardia followed by sustained hypotension, bradycadia and prolonged QTc. Remifentanil induced a dose-dependent QTc shortening with an increase in arterial pressures. Sotalol caused a decrease in HR and systolic arterial pressure with an increase in PR and QTc intervals. Dopamine induced an increase in arterial and pulse pressures. Methacholine increased tidal volume, respiratory rate and minute volume. DISCUSSION: The results suggest that the minipig is a valid alternative to other non-rodent species for cardiovascular and respiratory safety pharmacology studies when this species is justified.

Effect of citric acid on electrocardiographic parameters of broiler chickens with pulmonary hypertension.

To clarify the effect of orally administered citric acid on the electrocardiographic parameters of pulmonary hypertensive broilers, chicks were reared at high altitude and treated with citric acid for 45 days. Increase of cardiac indices such as right ventricle/total ventricles (RV/TV), RV/body weight and TV/body weight ratio was not observed in the treated groups as compared to the control groups. Decrease of S amplitude in the treated groups (leads II, III, aVF) was only significant (P < 0.05) at 45 days of age (leads II, aVF; 1.5 g/l of citric acid). There were significant reductions of T amplitude at 28 (lead aVR) and 36 days (lead aVL) and significant reductions of R wave at 28 (lead aVL, all doses of citric acid) and 45 days of age (lead aVR, 1 and 1.5 g/l citric acid) in the treated groups. The QRS interval was significantly higher at 28 (leads III and aVF), 36 (leads II, III and aVF, 1 g/l citric acid) and 45 days of age (leads II and aVF) in the treated groups. The QT interval was significantly (P < 0.05) increased at 28 and 45 days of age (lead aVL) and the RR interval also showed an increase at 28 (leads aVR and aVL) and 45 (lead aVL) days of age as compared to the controls. Our data indicate that citric acid modulates the induction of pulmonary hypertension at high altitude and this effect is detectable in the electrocardiographic parameters.

The effect of electro-acupuncture stimulation on rhythm of autonomic nervous system in dogs.

Effects of electro-acupuncture (EA) stimulation on the rhythm of the autonomic nervous system in dogs were studied. Six healthy beagles were used in this study. Each dog was separately kept in a cage, and repeatedly exposed to light for 12 hr and dark for 12 hr alternately. Fixed subject dogs were stimulated by use of 5-V, 250-musec, 2-Hz biphasic square pulses for 15 min at the Xuan Shu (GV-5) and Bai Hui (GV-20) points on the spine. After EA stimulation, electrocardiogram was recorded for 24 hr. From the electrocardiogram data, the heart rate (HR), coefficient of variation in the R-R intervals (CVRR; index of autonomic nervous activity), power of high frequency component (HF; index of vagal nervous activity), and ratio of powers of the low and high frequency components (LF/HF; index of sympathetic nervous activity) were obtained. Cosinor analysis demonstrated that these indices exhibited a significant rhythmicity (P<0.05), irrespective of EA stimulation. In LF/HF, EA stimulation advanced the acrophase (from 22:55 to 21:33, P=0.012), and elevated the midline-estimating statistic of rhythm (from 0.653 to 0.725, P=0.006). However, there was no significant difference in HR, CVRR, or HF. In conclusion, EA stimulation markedly influenced the rhythm of sympathetic nervous system in dogs.

Primary hypoparathyroidism in dogs: a retrospective study of 17 cases.

OBJECTIVE: To evaluate the clinico-pathological findings, response to treatment and prevalence of complications in dogs with primary hypoparathyroidism. DESIGN: Retrospective study of 17 dogs presenting to the University of Melbourne Veterinary Clinical Centre and Murdoch University Veterinary Hospital over a 15 year period (1990 to 2004). Case records were evaluated for signalment, body weight, diet type, historical and clinical findings, serum total calcium, phosphate, albumin and parathyroid hormone concentrations, urinary fractional excretion ratios of calcium and phosphate, electrocardiogram (ECG) results, treatments administered, outcome and period of follow-up. RESULTS: The most common breeds identified were St Bernard (three dogs), Chihuahua (two dogs), German Shepherd (two dogs) and Jack Russell Terrier (two dogs). Three dogs were cross bred. Seizures, muscle tremors and fasciculations, stiff gait, tetany, muscle cramping, behavioural change and hyperventilation were the most common clinical signs. Vomiting, inappetence, diarrhoea, abdominal pain, hyperthermia, facial pruritus, ataxia, weakness, cataracts, and circling also occurred with less frequency. The mean duration of observed clinical signs preceding diagnosis was 33 days (median 13 days, range 1 to 173 days). All dogs had marked hypocalcaemia with normal or mildly increased serum albumin concentrations. Mean phosphate concentrations were significantly higher in inappetent dogs (P = 0.049). Mean serum calcium concentrations were significantly lower in dogs with cataracts compared to those without (P = 0.046). There were no other significant relationships between serum calcium or phosphate concentrations and the clinical presentation or outcome. No significant correlations were identified between the presence of a particular clinical sign and the duration of clinical signs. ECGs were obtained in four dogs and all exhibited QT interval prolongation due to a ST-segment prolongation. Sixteen of 17 dogs were treated successfully for hypocalcaemia and discharged from hospital. Acute management included parenteral calcium gluconate (10 dogs) and intravenous anticonvulsants (five dogs). Chronic therapy included oral vitamin D analogues and calcium supplementation. Treatment complications occurred in two dogs and included acute renal failure (one dog) and iatrogenic tissue necrosis following subcutaneous calcium administration (one dog). The mean follow-up period was 14.5 months (median 13 months, range 0 to 39 months). Twelve dogs were alive at the last follow up and two dogs were euthanased for unrelated reasons. The type of vitamin D analogue used was not associated with outcome. CONCLUSION: Primary hypoparathyroidism was an uncommon diagnosis in dogs. Saint Bernards, cross bred dogs, German Shepherd dogs and Terrier breeds were most commonly affected. Neurological signs were the most common presenting clinical signs, although alimentary signs may have been more common than previously reported. Dogs with primary hypoparathyroidism appeared to have a good prognosis following initiation of calcium supplementation and vitamin D therapy. Complications of treatment were uncommon and could be minimised with regular monitoring.

Effects of fenoldopam mesylate on systemic hemodynamics and indices of renal function in normotensive neonatal foals.

BACKGROUND: Fenoldopam mesylate, a dopamine-1 receptor agonist, has dose- and species-dependent effects on hemodynamics and renal function. The effects of this drug in normotensive neonatal foals have not been reported. HYPOTHESIS: Two doses of fenoldopam would result in distinct changes in the systemic circulation, urine output, and creatinine clearance of neonatal foals. ANIMALS: Six Thoroughbred foals. METHODS: Each foal received 2 dosages of fenoldopam (low dose, 0.04 microg/kg/min; high dose, 0.4 microg/kg/min) and a control administration of saline, in a masked, placebo-controlled study. RESULTS: High-dosage fenoldopam had no effect on renal function but caused a significant increase in heart rate and decrease in mean, systolic and diastolic arterial blood pressure compared with saline. Low-dosage fenoldopam had no effects on systemic hemodynamics, significantly increased urine output, and had no significant effect on creatinine clearance or the fractional excretions of sodium, potassium, or chloride compared with saline. CONCLUSIONS AND CLINICAL IMPORTANCE: These data suggest that high-dosage fenoldopam increases heart rate, decreases arterial blood pressure, and has no significant effects on renal function, whereas low-dosage fenoldopam has no significant effects on systemic hemodynamics while increasing urine output. This contrast is unique to this species and warrants further investigation.

Clinical and pathological aspects of experimental oleander (Nerium oleander) toxicosis in sheep.

Dried Nerium oleander leaves at single lethal dose of 110 mg/kg body weight were administered orally to six native male sheep. Clinical signs of toxicosis in sheep began to appear about 30 min after receiving the oleander and included decrease of the heart rate followed by cardiac pauses and tachyarrhythmias; ruminal atony, mild to moderate tympany, abdominal pain, polyuria and polakiuria. Electrocardiography revealed bradycardia, atrio-ventricular blocks, depression of S-T segments, ventricular premature beats and tachycardia, and ventricular fibrillation. Five sheep died within 4-12 h and one survived. At necropsy there were varying degrees of haemorrhages in different organs and gastroenteritis. Histopathological examination of tissue sections revealed myocardial degeneration and necrosis, degeneration and focal necrosis of hepatocytes, necrosis of tubular epithelium in kidneys, oedema in the lungs, and ischemic changes in the cerebrum.

Effect of intratesticular injection of xylazine/ketamine combination on canine castration.

This study was performed to compare the effect of intratesticular (IT) injection of xylazine/ketamine combination for canine castration with those of intramuscular (IM) or intravenous (IV) injection. Xylazine and ketamine was administered simultaneously via intratesticularly (IT group), intramuscularly (IM group) or intravenously (IV group) at doses of 2 and 10 mg/kg, respectively. Pain response at the time of injection, mean induction time, mean arousal time, mean walking time and cardiopulmonary function during anesthesia were monitored after the xylazine and ketamine administration. In IV and IM groups, heart rates were significantly decreased 30 and 45 min after xylazine and ketamine administration, respectively (p < 0.05). Respiratory rates were significantly decreased in the IV group (p < 0.05). In the IT group, there was no significant changes in heart and respiratory rates. The occurrence of cardiac arrhythmias was less severe in IT group compared with those in IM and IV groups. The route of administration did not affect rectal temperature. Mean induction time was significantly (p < 0.05) longer in IT group than in IM and IV groups. On the contrary, mean arousal time and mean walking time were shortened in IT group. Clinical signs related to pain response at the time of injection and vomiting were less observed in IT group than in IM group, and head shaking was less shown in IT group than in IM and IV groups during recovery period. These results indicated that intratesticular injection of xylazine/ketamine for castration has several advantages such as less inhibition of cardiopulmonary function and fast recovery from anesthesia without severe complications, and would be an effective anesthetic method for castration in small animal practice.

Taurine deficiency in dogs with dilated cardiomyopathy: 12 cases (1997-2001).

OBJECTIVE: To determine signalment, history, clinical signs, blood and plasma taurine concentrations, electrocardiographic and echocardiographic findings, treatment, and outcome of dogs with low blood or plasma taurine concentrations and dilated cardiomyopathy (DCM). DESIGN: Retrospective study. ANIMALS: 12 client-owned dogs with low blood or plasma taurine concentrations and DCM. PROCEDURE: Medical records were reviewed, and clinical data were obtained. RESULTS: All 12 dogs were being fed a commercial dry diet containing lamb meal, rice, or both as primary ingredients. Cardiac function and plasma taurine concentration improved with treatment and taurine supplementation. Seven of the 12 dogs that were still alive at the time of the study were receiving no cardiac medications except taurine. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that consumption of certain commercial diets may be associated with low blood or plasma taurine concentrations and DCM in dogs. Taurine supplementation may result in prolonged survival times in these dogs, which is not typical for dogs with DCM. Samples should be submitted for measurement of blood and plasma taurine concentrations in dogs with DCM, and taurine supplementation is recommended while results of these analyses are pending.