Quantitative assessment of two- and three-dimensional transthoracic and two-dimensional transesophageal echocardiography,computed tomography,and magnetic resonance imaging in normal canine hearts

IntroductionThe objective of the study was to evaluate the accuracy of two- and three-dimensional (2D, 3D) transthoracic echocardiography (TTE), 2D transesophageal echocardiography, and computed tomography angiography (CTA) compared with cardiac magnetic resonance imaging (CMR) in normal dogs and to assess repeatability of 2D and 3D TTE for the assessment of left ventricular (LV) and left atrial (LA) dimensions.AnimalsThe study was performed on six healthy dogs.Materials and MethodsTransthoracic echocardiography, transesophageal echocardiography, CTA, and CMR were performed on each dog. Right ventricular (RV) and LV volumes (in systole and diastole), ejection fraction (EF), and LA and right atrial (RA) volumes were assessed. Repeatability and intrarater and interrater measurements of variability were quantified by average coefficient of variation (CV) for 2D and 3D TTE.ResultsNo clinically relevant differences in LV volume were detected between CMR and all modalities. Importantly, 3D TTE had the lowest CV (6.45%), correlated with (r_s = 0.62, p = 0.01), and had the highest overlap in distribution with CMR (OVL >80%). Left ventricular EF and LA size via CTA compared best with CMR and RV and RA volumes were best estimated by 3D TTE. Assessment of LV and LA volumes via 3D TTE had moderate repeatability (15–21%) compared with LV M-mode measurements and 2D LA-to-aortic ratio (<10%), respectively. For LV size, interrater CV for 3D TTE (19.4%) was lower than 2D TTE (23.1%).ConclusionsMeasurements of LV, RV, and RA volumes via 3D TTE and LA volume and LV EF assessed by CTA compared best with CMR. Three-dimensional echocardiography had lower interrater and intrarater CV compared with 2D TTE.     

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.     

Outcome of intensity‐modulated radiation therapy‐based stereotactic radiation therapy for treatment of canine nasal carcinomas

Stereotactic radiation therapy (SRT) has emerged as a convenient definitive treatment modality in veterinary medicine, but few studies exist evaluating outcome with treatment for canine nasal tumors, and no studies report the treatment of one single tumor histotype. This retrospective, observational study evaluates toxicity, response, and survival in 17 dogs with nasal carcinomas treated with SRT. Dogs received a median of 3000 centigray in three fractions via 6‐MV linear accelerator. Eighty‐eight percent of patients (n = 15) demonstrated clinical benefit. Of dogs with repeated CT imaging (n = 10), 60% (n = 6) achieved a partial response and 10% (n = 1) achieved a complete response. Median progression‐free survival (PFS) was 359 days. Median survival time (MST) was 563 days. Among dogs evaluable for acute toxicity, 50% (n = 10) developed low grade toxicity (grade 1, n = 4; grade 2, n = 1). No patients developed grade 3 toxicity. 16 dogs (87%) evaluable over the long term developed signs consistent with possible late toxicity. The majority of late toxicities were mild (alopecia, hyperpigmentation, and leukotrichia n = 10; ocular discharge and keratoconjunctivitis sicca n = 5). Thirty‐seven percent of patients (n = 6) developed seven possible grade 3 late toxicities (blindness, n = 3; fistula, n = 1; seizures, n = 3), which were difficult to distinguish from progressive disease in most patients. Of the prognostic factors evaluated (demographics, tumor stage, dosimetric data, epistaxis, facial deformity, clinical response, image‐based response, nonsteroidal anti‐inflammatory drugs, and chemotherapy), only clinical response was a positive prognostic factor on MST (P < .00). No factors were found to be significantly associated with PFS.     

Reference intervals for the activity of lactate dehydrogenase and its isoenzymes in the serum and cerebrospinal fluid of healthy canines

Background

Lactate dehydrogenase (LD) exists as 5 isoenzymes (LD‐1 through LD‐5) that are expressed throughout the body and can be detected in both serum and cerebrospinal fluid (CSF). LD and its isoenzymes have been relatively unstudied in veterinary medicine, although studies in human medicine have demonstrated that changes in total LD activity and atypical isoenzyme patterns can indicate disease processes, including neurologic abnormalities.

Objectives

The purpose of this study was to establish RIs for LD and its isoenzymes in the serum and CSF of clinically healthy dogs. By establishing a definitive RI for this enzyme in healthy canines, further study of the clinical and diagnostic usefulness of LD can be undertaken.

Methods

Serum and atlantoaxial CSF were collected from clinically healthy dogs. Total LD activity was measured spectrophotometrically immediately after collection. Isoenzyme distributions were also determined within 8 hours of collection using the QuickGel LD Isoenzyme technique and a densitometric scanner.

Results

The median serum total LD in healthy canines was 69.0 U/L (n = 41; range: 21.0‐217.0 U/L), while the median CSF total LD was 10.0 U/L (n = 40; range: 6.0‐19.3 U/L). LD‐5 is the predominant isoenzyme in canine serum (n = 40), contributing over half of the total enzyme activity. Conversely, in canine CSF (n = 42), LD‐1 is the predominant isoenzyme, followed by LD‐2 and LD‐3.

Conclusions

Knowledge of the distribution and concentration of LD in the serum and CSF of healthy dogs will set the foundation for future studies of canine LD as a potentially clinically useful biomarker.     

Effect of benazepril and pimobendan on serum angiotensin‐converting enzyme activity in dogs

To support their combined use, the objective of the study was to evaluate the effects of benazepril and pimobendan on serum angiotensin‐converting enzyme (ACE) activity in dogs. A total of 48 healthy beagle dogs were randomized into four groups (n = 12 per group) in a parallel‐group design study: A (control, placebo twice daily (BID)); B (0.5–1.0 mg/kg benazepril once daily (SID) in the morning, placebo in the evening); C (0.25–0.5 mg/kg benazepril BID); D (0.25–0.5 mg/kg benazepril and 0.125–0.25 mg/kg pimobendan, both BID). The test items were administered orally for 15 days. Serum ACE activity was measured on days 1 and 15. Groups B, C and D had significantly lower average serum ACE activity compared to baseline and to the control group, on both days 1 and 15. There were no significant differences in average ACE activity between groups B, C and D. Noninferiority of group C to B was demonstrated. In conclusion, 0.25–0.5 mg/kg benazepril administered BID produced noninferior inhibition of serum ACE activity compared to 0.5–1.0 mg/kg benazepril dosed SID. Pimobendan had no significant effect on benazepril's action on serum ACE activity. The results support the use of benazepril BID in dogs and in combination with pimobendan.     

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.     

Comparison between dexmedetomidine and acepromazine in combination with methadone for premedication in brachycephalic dogs undergoing surgery for brachycephalic obstructive airway syndrome

ObjectiveTo compare dexmedetomidine with acepromazine for premedication combined with methadone in dogs undergoing brachycephalic obstructive airway syndrome (BOAS) surgery.Study designRandomized, blinded clinical study.AnimalsA group of 40 dogs weighing mean (± standard deviation) 10.5 ± 6 kg, aged 2.6 ± 1.9 years.MethodsDogs received either acepromazine 20 μg kg^–1 (group A) or dexmedetomidine 2 μg kg^–1 (group D) intramuscularly with methadone 0.3 mg kg^–1. Anaesthesia was induced with propofol and maintained with sevoflurane. Sedation (0–18), induction (0–6) and recovery (0–5) qualities were scored. Propofol dose, hypotension incidence, mechanical ventilation requirement, extubation time, additional sedation, oxygen supplementation, regurgitation and emergency intubation following premedication or during recovery were recorded. Data were analysed using t tests, Mann-Whitney U or Chi-square tests.ResultsGroup A dogs were less sedated [median (range): 1.5 (0–12)] than group D [5 (1–18)] (p = 0.021) and required more propofol [3.5 (1–7) versus 2.4 (1–8) mg kg^–1; p = 0.018]. Induction scores [group A: 5 (4–5); group D 5 (3–5)] (p = 0.989), recovery scores [group A 5 (4–5); group D 5(3–5)](p = 0.738) and anaesthesia duration [group A:93 (50–170); group D 96 (54–263) minutes] (p = 0.758) were similar between groups. Time to extubation was longer in group A 12.5 (3-35) versus group D 5.5 (0–15) minutes; (p = 0.005). During recovery, two dogs required emergency intubation (p > 0.99) and five dogs required additional sedation (p > 0.99). Oxygen supplementation was required in 16 and 12 dogs in group A and D, respectively (p = 0.167); no dogs in group A and one dog in group D regurgitated (p = 0.311).Conclusions and clinical relevanceDexmedetomidine 2 μg kg^–1 produces more sedation but similar recovery quality to acepromazine 20 μg kg^–1 combined with methadone in dogs undergoing BOAS surgery.     

Utility of N-terminal pro-brain natriuretic peptide for assessing hemodynamic significance of patent ductus arteriosus in dogs undergoing ductal repair

ObjectiveDetermine if plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) correlates with markers of hemodynamically significant patent ductus arteriosus (PDA) in dogs.AnimalsTen dogs with PDA and 30 healthy dogs of similar ages.MethodsProspective case series with control population. Dogs with PDA were initially evaluated with thoracic radiographs, transthoracic echocardiography, pulmonary capillary wedge pressure (PCWP) and NT-proBNP. Following ductal occlusion, NT-proBNP and echocardiography were repeated within 24 h and at day 90. PCWP was repeated at day 90. Correlation between NT-proBNP and hemodynamic measurements was assessed, and accuracy of NT-proBNP for identifying PDA severity was estimated.ResultsNT-proBNP was significantly higher (median; absolute range) in dogs with PDA (895; 490–7118 pmol/L) than controls (663; 50–1318 pmol/L) (p = 0.025). NT-proBNP decreased significantly 90 days post-ductal closure (597; 154–1858 pmol/L) (p = 0.013). Left atrial and ventricular size decreased significantly within 24 h and at day 90 as did PCWP (day 90 only). NT-proBNP correlated with vertebral heart size (VHS) and indexed left ventricular systolic diameter (iLVIDs); concentrations ≥ 1224 pmol/L distinguished dogs with elevated VHS and iLVIDs.ConclusionsNT-proBNP is elevated in dogs with PDA, decreases following PDA closure and correlates with select radiographic and echocardiographic markers of cardiac remodeling.     

Treatment of myeloid neoplasia with doxorubicin and cytarabine in 11 dogs

Myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML) are primary myeloid neoplasms in dogs generally considered to have a poor outcome. In this study, we assessed toxicity, efficacy and outcome of concurrent administration of doxorubicin and cytarabine in 11 dogs with myeloid neoplasia. Bone marrow specimens were reviewed by three pathologists and classified as either MDS (n = 2), high grade MDS/early AML (MDS/AML; n = 4) or AML (n = 5). The median number of treatment cycles was 5 (range 1–9) and resolution of cytopenia was reported in 7 of 11 dogs including 2 dogs with MDS, 2 dogs with MDS/AML, and 3 dogs with AML. The median duration of remission in the seven responders was 344 days (range 109–1428) and the median overall survival for all dogs was 369 days. Adverse events consisted of predominantly low-grade gastrointestinal illness and myelosuppression. Three dogs developed grade V toxicity manifesting with heart failure (n = 2) at 369 and 1170 days after diagnosis and acute gastrointestinal side effects (n =1). Despite a limited sample size, these results suggest that a doxorubicin and cytarabine protocol may be considered as a therapeutic option in dogs with myeloid neoplasia. Protocol safety, in particular regarding myocardial toxicity, and efficacy should be further investigated.     

Plasma‐Free Metanephrine and Free Normetanephrine Measurement for the Diagnosis of Pheochromocytoma in Dogs

Background

Measurement of plasma‐free metanephrines is the test of choice to identify pheochromocytoma in human patients.

Objectives

To establish the sensitivity and specificity of plasma‐free metanephrine (fMN) and free normetanephrine (fNMN) concentrations to diagnose pheochromocytoma in dogs.

Animals

Forty‐five client‐owned dogs (8 dogs with pheochromocytoma, 11 dogs with adrenocortical tumors, 15 dogs with nonadrenal disease, and 11 healthy dogs.)

Methods

A prospective study. EDTA plasma was collected from diseased and healthy dogs and submitted for fMN and fNMN measurement by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS).

Results

Free MN concentration (median [range]) was significantly higher in dogs with pheochromocytoma (8.15 [1.73–175.23] nmol/L) than in healthy dogs (0.95 [0.68–3.08] nmol/L; P < .01) and dogs with adrenocortical tumors (0.92 [0.25–2.51] nmol/L; P < .001), but was not different from dogs with nonadrenal disease (1.91 [0.41–6.57] nmol/L; P ≥ .05). Free NMN concentration was significantly higher in dogs with pheochromocytoma (63.89 [10.19–190.31] nmol/L) than in healthy dogs (2.54 [1.59–4.17] nmol/L; P < .001), dogs with nonadrenal disease (3.30 [1.30–10.10] nmol/L; P < .001), and dogs with adrenocortical tumors (2.96 [1.92–5.01] nmol/L); P < 0.01). When used to diagnose pheochromocytoma, a fMN concentration of 4.18 nmol/L had a sensitivity of 62.5% and specificity of 97.3%, and a fNMN concentration of 5.52 nmol/L had a sensitivity of 100% and specificity of 97.6%.

Conclusions and Clinical Importance

Plasma fNMN concentration has excellent sensitivity and specificity for the diagnosis of pheochromocytoma in dogs, whereas fMN concentration has moderate sensitivity and excellent specificity. Measurement of plasma‐free metanephrines provides an effective, noninvasive, means of identifying dogs with pheochromocytoma.     

Anatomical Variations of the Blood Vascular System in Veterinary Medicine: The Internal Iliac Artery of the Dog — Part Three

The aim of this study was to analyse and describe the variability of the umbilical artery. Two hundred and thirty‐two pelvic halves from 116 adult dogs were examined. To study the permeability of the umbilical artery, ten adult dogs, nine newborns and thirteen foetuses between 35 and 50 days of gestation were also used. In relation to the origin of the umbilical artery, six anatomical variations were found. From which five involved a cranial (n = 4) or caudal (n = 1) relocation of its origin, and in one case (n = 1), the umbilical artery arose from the median sacral artery. In eight cases, the umbilical artery gave off the prostatic (n = 1) or vaginal (n = 7) arteries. The permeability of the umbilical artery was the most significant anatomical variation: permeability was detected in 45% (106 of 232 pelvic halves) of all cases, from which 36 were males and 70 females. Interestingly, an equal vascular permeability in both hemipelvises was found for 82% of the dogs, thus additional data related to such feature of the umbilical artery was also recorded. In accordance with the statistical study, the main anatomical variations described showed significant values for gender, side of the body, size and profile variables.     

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.     

Computed tomographic‐lymphography as a complementary technique for lymph node staging in dogs with malignant tumors of various sites

Locoregional lymph nodes are routinely examined in order to define the spatial extent of neoplastic disease. As draining patterns of certain tumor types can be divergent from expected anatomical distribution, it is critical to sample the lymph nodes truly representing the draining area. The aim of this bicenter prospective pilot study was to describe the technique of computed tomographic (CT)‐lymphography for primary draining lymph node mapping in tumor staging in dogs. Forty‐five dogs with macro‐ or microscopic tumors in specified localizations were evaluated. Depending on body weight, 0.8–2 ml contrast agent (iohexol) was injected into four quadrants around the tumor, and CT‐images were obtained at 1, 3, 6, 9, and 12 minutes post‐injection. Attenuation of chosen regions of interest (Hounsfield units (HU)) and patterns of enhancement were assessed for 284 lymph nodes in the precontrast study with median HUs of 31.1 (Interquartile range (IQR) = 18.4) and for 275 in the intravenous postcontrast study with 104.3 HU (IQR = 31.2) (paired Wilcoxon test, P < 0.001). In the CT‐lymphography study, 45 primary draining lymph nodes with a significantly higher median HU value of 348.5 (IQR = 591.4) (one‐sample t‐test, P < 0.001) were identified. Primary draining lymph nodes were found to be clearly visible after 1–3 minutes after local injection, often concurrent with a good visibility of the lymphatic vessel system. The herein described technique of peritumorally injected CT‐contrast agent followed by subsequent CT‐lymphography for primary draining lymph node mapping works well in a majority of cases in all investigated sites and warrants further validation for different tumor entities.     

Prospective clinical trial evaluating spironolactone in Doberman pinschers with congestive heart failure due to dilated cardiomyopathy

Introduction/objectivesWhether the aldosterone antagonist spironolactone has beneficial survival effects in dogs with dilated cardiomyopathy (DCM) is not known. The primary objective of the study was to evaluate the effect of spironolactone, when added to conventional therapy, on survival time in Doberman pinschers with congestive heart failure (CHF) due to DCM.AnimalsSixty-seven client-owned Doberman pinschers with CHF due to DCM.Materials and methodsThe trial design was prospective, randomized, blinded, and placebo controlled. Dogs were randomized to receive 50–75 mg of spironolactone twice daily (n = 34) or a placebo (n = 33), in addition to standard CHF therapy. Follow-up visits were targeted every one–six weeks until endpoint. Quality-of-life questionnaire and physical examination were performed at every visit, while renal biochemistry, ECG, echocardiography, and thoracic radiography were reassessed as needed. The primary endpoint was time to cardiac death, defined as death or euthanasia from CHF or sudden death.ResultsMedian time to primary endpoint in the spironolactone group (183 days) was not statistically significantly different than that for the placebo group (124 days) (P = 0.254). The development of atrial fibrillation (AF) was significantly less frequent in the spironolactone group (n = 7) than the placebo group (n = 15, P = 0.037).ConclusionsWhile median time to cardiac death in the spironolactone group was not statistically significantly different than that in the placebo group, adding spironolactone to conventional therapy resulted in reduced occurrence of AF.     

Change of Vertebral Left Atrial Size in Dogs With Preclinical Myxomatous Mitral Valve Disease Prior to the Onset of Congestive Heart Failure

Introduction/objectivesIt has been proposed that vertebral left atrial size (VLAS) on thoracic radiographs can be used to assess the left atrial enlargement in dogs with myxomatous mitral valve disease (MMVD). However, it remains unclear whether VLAS can be used to distinguish dogs between pre-clinical MMVD that are at a greater risk of developing congestive heart failure (CHF) from those at a lower risk. We investigated this possibility.Animals, materials and methodsForty-one dogs with MMVD were retrospectively classified into one of two groups, a group that developed CHF (group CHF, n = 17) or remained CHF-free (group no-CHF, n = 24). The value of vertebral heart scale (VHS) and VLAS at three time-points, change in VHS and VLAS at a specific time interval (ΔVHS, ΔVLAS) and rate of change in the values per month (ΔVHS/month, ΔVLAS/month) were compared.ResultsAt the first visit, there were no significant differences in VLAS between the groups. At the median of 105 (interquartile ranges 83–155) days prior to the onset of CHF (group CHF) or the last visit (group no-CHF), VLAS was significantly higher in group CHF (mean, 2.9; standard deviation ± 0.4) than in group no-CHF (2.6 ± 0.3) (p = 0.028). ΔVLAS/month (area under the curve, 0.91; p<0.001) showed high diagnostic accuracy in distinguishing which dogs would develop CHF within 180 days and which would not.ConclusionsVLAS and ΔVLAS/month in dogs with pre-clinical MMVD may be useful to identify dogs at risk of developing CHF within the next 180 days.     

Microdose computed tomographic cardiac angiography in normal cats

ObjectivesTo determine if microdose contrast-enhanced multi-detector computed tomographic angiography (MDCTA) allows characterization of cardiac chambers in lightly sedated normal cats.AnimalsSeven healthy domestic cats.MethodsLightly sedated normal cats were imaged pre-contrast and with microdose (0.22 ml/kg of non-ionic iodinated contrast medium, 300 mg I/ml) triple-phase MDCTA in a motion restriction device.ResultsOn pre-contrast images, the aorta (median: 52.43 Hounsfield units [HU], range 27.35–76.74 HU) was outlined by significantly (p = 0.015) lower attenuating periaortic fat (−66.16 HU, −42.62 to −92.77 HU). On post-contrast images, median peak contrast enhancement in the right ventricle (111.77 HU, 36.09–141.60 HU) was achieved in 3.1 s (range 2.9–7.3 s), in the aorta (149.30 HU, 99.43–319.60 HU) and left atrium (180.83 HU, 88.53–266.84 HU) in 6.4 s (range 5.6–7.7 s) and in the left ventricle (147.89 HU, 57.23–245.77 HU) in 7.10 s (range 6.2–11.2 s). Significantly higher attenuation was measured between all chambers and walls, the right ventricular lumen and interventricular septum (median ratio 53.78 HU, range 0.21–83.20 HU), left ventricular lumen and left ventricular free wall (89.32 HU, 38.81–185.95 HU) and aorta and periaortic fat (190.43 HU, 143.22–425.44 HU) on post-contrast images.ConclusionsSufficient biological contrast is available on survey CT to discriminate between the aorta and the left atrium, and microdose MDCTA provides sufficient contrast enhancement for adequate visualization of the heart chambers in normal cats.     

Association of QRS duration and survival in dogs with dilated cardiomyopathy: A retrospective study of 266 clinical cases

ObjectiveThe purpose of this study was to investigate the prognostic value of QRS duration in dogs with dilated cardiomyopathy (DCM) by studying its relationship with survival time.MethodsThe medical records of dogs diagnosed with DCM were retrospectively searched for good quality ECG tracings. The QRS duration was measured from the ECG tracing and two different models were used: binary variable (dogs were divided into 2 groups based on a QRS duration of <60 ms or ≥60 ms) and continuous variable. The survival times were analysed by the Kaplan-Meier method and Cox’s proportional hazard model.Results266 dogs met the inclusion and exclusion criteria. A QRS duration ≥60 ms was associated with a reduced survival time compared to those with a QRS duration <60 ms (Hazard Ratio of 1.34, 95% CI 1.05–1.71, P = 0.02). When considered as a continuous variable the Hazard Ratio was 1.015 for each increase in QRS duration of 1 ms (95% CI 1.006–1.024, p = 0.001).Dogs with a QRS duration < 60 ms had a median survival time (IQ range) of 25 weeks (97-65) and dogs with a QRS duration ≥60 ms had a median survival time (IQ range) of 13 weeks (3–34).ConclusionThe measurement of QRS duration is relatively simple to perform from a surface ECG recording. A duration ≥60 ms is associated with shorter survival times in dogs with DCM, which may provide practitioners with additional prognostic information.     

Association between atrial fibrillation and right-sided manifestations of congestive heart failure in dogs with degenerative mitral valve disease or dilated cardiomyopathy

IntroductionTo determine whether dogs with atrial fibrillation (AF) are more likely to develop right-sided manifestations of congestive heart failure (R-CHF) than dogs without AF.AnimalsTwo hundred twenty dogs diagnosed with congestive heart failure (CHF) secondary to degenerative mitral valve disease (DMVD, n = 155) or dilated cardiomyopathy (DCM, n = 65) at a referral institution.MethodsMedical records were reviewed to extract relevant clinical and echocardiographic data.ResultsFifty dogs had AF at the time of CHF diagnosis, including 17/155 (11.0%) dogs with DMVD and 33/65 (50.8%) dogs with DCM. Sixty dogs had R-CHF evidenced by cavitary effusions. Among DMVD dogs, R-CHF occurred in 13/17 (76.5%) dogs with AF compared with 10/138 (7.2%) dogs without AF; among DCM dogs, R-CHF occurred in 24/33 (72.7%) dogs with AF compared with 13/32 (40.6%) dogs without AF. Dogs with AF were more likely to manifest R-CHF signs than dogs without AF (p < 0.0001 for DMVD; p = 0.0125 for DCM). The presence of AF, diagnosis of DCM, and moderate to severe tricuspid regurgitation were associated with R-CHF in multivariate analysis. AF was the strongest predictor of R-CHF (odds ratio, 14.44; 95% confidence interval, 5.75–36.26).ConclusionsDogs with AF are more likely to manifest R-CHF than dogs without AF. Cavitary effusions are an expected finding in approximately three-quarters of dogs with AF and CHF secondary to either DCM or DMVD.     

Power and Pulsed Doppler Evaluation of Prostatic Artery Blood Flow in Normal and Benign Prostatic Hyperplasia–Affected Dogs

This study was carried out with the objectives to test the differences in the haemodynamic characteristics of the prostatic artery in normal and benign prostatic hyperplasia (BPH)–affected dogs using Doppler ultrasonography. In sixteen male German shepherd dogs, prostatic volume was detected and prostatic biopsy was performed. The prostatic artery blood flow parameters determined were as follows: peak systolic velocity (PSV), end diastolic velocity (EDV), Resistive Index (RI) and Pulsatility Index. The power Doppler mode was used for colour flow mapping of the prostatic artery. In PW mode at marginal locations, the waveforms recorded showed a continuous pattern typical of the high‐resistance vessels, while in subcapsular locations, the waveforms recorded were continuous characteristic of the low‐resistance vessel. Peak systolic velocity and EDV in both locations were significantly higher in BPH group (p < 0.001) than normal group (p < 0.05). Pixel number in BPH group in both locations was significantly higher (p < 0.05) compared to the normal group. This study shows that Doppler ultrasonography represents a valid and non‐invasive method for the characterization of the blood flow in the prostatic artery in dogs affected with BPH. Moreover, statistically significant differences of blood flow velocities in prostatic artery in normal and BPH‐affected dogs were detected. The RI was not able to differentiate normal dogs from dogs affected by BPH and therefore is not a parameter usable for diagnostic purposes, while Power Doppler could represent an additional diagnostic tool.