Clinical presentation, management, and survival in dogs with persistent atrial standstill in the United Kingdom.

OBJECTIVES: To investigate the clinical and echocardiographic presentation of dogs with persistent atrial standstill (PAS), identify variables measured at first presentation that could predict their survival, and document the progression of the disease after pacing. MATERIALS AND METHODS: Retrospective study of medical records of dogs diagnosed with PAS at three referral hospitals of the United Kingdom over seven years. RESULTS: Twenty-six dogs were diagnosed with PAS during the study period. Median age of the population was three years (range: seven months-12.5 years). The most common clinical sign was syncope (14/26). Twenty-four dogs received artificial pacemakers (PM). Major complications after PM implantation were observed in four dogs (four/24). Serial echocardiographic examinations showed that cardiac dimensions of PAS dogs with left atrial or left ventricular dilation at first presentation did not return to reference range after pacing. Further dilation of the cardiac chambers, recurrence of congestive heart failure (CHF), or development of new episodes of CHF were documented in seven, four, and 10 PAS dogs, respectively, despite pacing. Median survival time for cardiac-related deaths after PM implantation was 1512 days (18-3207). Neither CHF nor echocardiographic variables at presentation predicted survival after PM implantation in PAS dogs. CONCLUSIONS: Persistent atrial standstill (PAS) is an uncommon bradyarrhythmia, occurring in young adult dogs. Affected dogs were often presented with syncope. Whilst syncope resolved, cardiac remodeling persisted after PM implantation. Long-term survival was favorable after PM implantation and was not predicted by congestive status or cardiac chamber size at first presentation.

Long-term outcome and troponin I concentrations in Great Danes screened for dilated cardiomyopathy: an observational retrospective epidemiological study.

INTRODUCTION: Dilated cardiomyopathy (DCM) is common in Great Danes (GDs) but screening for this condition can be challenging. We hypothesised that cardiac troponin-I (cTnI) concentration is elevated in GDs with DCM and/or ventricular arrhythmias (VAs), and is associated with reduced survival time in GDs. ANIMALS: One hundred and twenty-four client-owned GDs assigned echocardiographically as normal (n = 53), equivocal (n = 37), preclinical DCM (n = 21), or clinical DCM (n = 13). MATERIALS AND METHODS: A retrospective epidemiological study. Echocardiographic diagnosis, VAs, and contemporaneous cTnI concentrations were recorded. Diagnostic accuracy and cTnI cut-offs were determined with receiver operating characteristic analyses. Effects of the cTnI concentration and disease status on survival and cause of death were explored. RESULTS: Median cTnI was greater in clinical DCM (0.6 ng/mL [25th-75th percentiles: 0.41-1.71 ng/mL]) and GDs with VAs (0.5 ng/mL [0.27-0.80 ng/mL], P<0.001). Elevated cTnI detected these dogs with good accuracy (area under the curve: 0.78-0.85; cut-offs 0.199-0.34 ng/mL). Thirty-eight GDs (30.6%) suffered a cardiac death (CD); GDs suffering CD (0.25 ng/mL [0.21-0.53 ng/mL]) and specifically sudden cardiac death (SCD) (0.51 ng/mL [0.23-0.72 ng/mL]) had higher cTnI than GDs dying of other causes (0.20 ng/mL [0.14-0.35 ng/mL]; P<0.001). Elevated cTnI (>0.199 ng/mL) was associated with shorter long-term survival (1.25 years) and increased risk of SCD. Great Danes with VAs had shorter survival times (0.97 years). CONCLUSIONS: A cardiac troponin-I concentration is a useful adjunctive screening tool. Elevated cTnI is a negative prognostic indicator.

Infective endocarditis in dogs in the UK: 77 cases (2009-2019).

OBJECTIVES: To determine the causative organisms, clinical features and outcome of canine infective endocarditis in the UK. MATERIALS AND METHODS: Medical records of three veterinary referral hospitals were searched for dogs with infective endocarditis between December 2009 and December 2019. Signalment, clinical signs, causative organism, valve affected, treatment and survival data were recorded. RESULTS: Seventy-seven cases with possible or definite infective endocarditis (according to the modified Duke criteria) were included. The majority were large breed (40/77 - 51.9%). There were 47 of 77 (61%) male dogs and the mean age was 7.3 ±3 years. A causative organism was identified in 26 of 77 (33.8%) cases. The most common organisms were Escherichia coli (7/27 - 25.9%), Pasteurella spp. (5/27 - 18.5%), Staphylococcus spp. (4/27 - 14.8%) and Corynebacterium spp. (4/27 - 14.8%). Bartonella spp. were not detected in any patients. The mitral valve was most commonly affected (48/77 - 62.3%). Clinical features were non-specific, with lethargy being the most common clinical sign observed (53/77 - 68.8%). Fifty-three dogs (68.8%) survived to discharge. The median survival time post discharge was 425 days (2 to 3650 days). The development of congestive heart failure was associated with a poorer outcome. Cardiac troponin concentration, antithrombotic use and the development of thromboembolism or arrhythmias were not significantly associated with outcome. CLINICAL SIGNIFICANCE: Some dogs with infective endocarditis that survive to discharge can have a long lifespan. The inability to detect an underlying organism is common and Bartonella spp. may be a less prevalent cause of canine infective endocarditis in the UK than in the USA.

The effect of obesity and subsequent weight reduction on cardiac structure and function in dogs.

BACKGROUND: In people, the cardiovascular effects of obesity include systemic hypertension, cardiac remodelling and both systolic and diastolic dysfunction, whilst weight reduction can reverse myocardial remodelling and reduce risk of subsequent cardiovascular disease. To date, variable results are reported in studies of the effect of obesity and controlled weight reduction on cardiovascular morphology and function in dogs. This prospective study aimed to assess cardiac function, heart rate variability, cardiac biomarkers and body composition before and after weight reduction in pet dogs with obesity. Twenty-four client-owned dogs referred for weight management due to obesity were recruited. To assess the cardiac effects of obesity, body composition analysis (by dual energy X-ray absorptiometry, DEXA) and cardiovascular assessment (echocardiography, Doppler blood pressure, electrocardiography, cardiac biomarkers) were performed prior to weight management. Twelve dogs completed the study and reached target weight, receiving a further cardiovascular assessment and DEXA. A Wilcoxon-signed rank test was used to compare each variable pre- and post- weight reduction. RESULTS: Median (interquartile range) duration of weight loss was 224 days (124-245 days), percentage weight loss was 23% (18-31%) of starting weight. Median change in body fat mass was -50% (-44% to -55%; P = 0.004), whilst median change in lean mass was -7% (+ 1% to -18%, P = 0.083). Before weight reduction, diastolic dysfunction (evidence of impaired relaxation in all dogs), increased left ventricular wall thickness and mildly elevated systolic blood pressure (14/24 ≥ 160 mmHg, median 165 mmHg (140-183)) were common features in dogs with obesity. However, systolic left ventricular wall dimensions were the only variables that changed after weight reduction, with a decrease in both the systolic interventricular septum (P = 0.029) and systolic left ventricular free wall (P = 0.017). There was no evidence of decreased heart rate variability in dogs with obesity (P = 0.367), and no change in cardiac biomarker concentrations with weight reduction (N-terminal proBNP, P = 0.262; cardiac troponin I P = 0.657). CONCLUSIONS: Canine obesity results in diastolic dysfunction and left ventricular hypertrophy, the latter of which improves with significant weight and fat mass reduction. Further studies are required to clarify the clinical consequences of these findings.

Cor triatriatum dexter of unusual morphology in a miniature schnauzer.

A five-year-nine-month-old, male entire, miniature schnauzer presented for further investigation of pleural effusion. Echocardiography revealed a perforated membrane dividing the right atrium into two chambers: the true right atrium (a small, lower-pressure, cranioventral chamber communicating with the tricuspid valve and right ventricle) and the accessory right atrium (a larger, higher-pressure, caudodorsal chamber), consistent with a cor triatriatum dexter. This was confirmed using computed tomography angiography. Imaging studies revealed that both the cranial and caudal vena cava entered the higher-pressure accessory right atrium and the coronary sinus entered both the accessory and true right atrial chambers. This differed from the more usual canine cor triatriatum dexter presentation with the cranial vena cava entering the lower-pressure cranial chamber and the caudal vena cava entering the higher-pressure caudal chamber. Balloon membranostomy was successful in reducing the pressure gradient between the two right atrial chambers with subsequent resolution of the clinical signs. The patient continues to do well after three-years of follow-up.

Effect of cilobradine in cats with a first episode of congestive heart failure due to primary cardiomyopathy.

INTRODUCTION: Heart rate (HR) is often elevated in cats with cardiomyopathies (CMPs). Pharmacologic modulation of HR may reduce cardiac morbidity and mortality. OBJECTIVES: To investigate the effects of cilobradine vs. placebo, regarding time to cardiac mortality or morbidity in cats with first episode of congestive heart failure (CHF) due to primary CMP. ANIMALS: Three hundred and sixty-seven client-owned cats with primary CMP that had presented with a first episode of CHF at 50 centers in Europe. Per-protocol population comprised 193 cats (n = 89 cilobradine, n = 104 placebo). An interim analysis for futility was planned. METHODS: Prospective, randomized, placebo-controlled, double-blinded, multicenter clinical trial. Primary outcome variable was the time to a composite of cardiac mortality or cardiac morbidity. RESULTS: Median time to primary outcome was 84 days (95% confidence interval [CI]: 63-219 days) in the cilobradine group (CG) and 203 days in the placebo group (95% CI: 145-377 days) with observed hazard ratio of 1.44, indicating a higher hazard for the CG (P = 0.057). Mean HR was 28 beats per minute (bpm) lower at Day 7 (P < 0.0001) and remained 29 bpm lower at Day 360 (P = 0.026) in the CG than that in the placebo group. Although the number of adverse events did not differ, there were more serious adverse events in the CG. CONCLUSIONS: Heart rate reduction by cilobradine in cats with a first episode of CHF due to primary CMP did not reduce cardiac mortality and morbidity.

Echocardiographic reference intervals in healthy UK deerhounds and prevalence of preclinical dilated cardiomyopathy: a prospective, longitudinal study.

BACKGROUND: Sighthounds have high echocardiographic (ECHO) left ventricular volumes. Establishing robust breed-specific ECHO reference intervals (RI) for screening is important. End-diastolic volume index (EDVI), end-systolic volume index (ESVI) and ejection fraction (EF) reference ranges derived by Simpson's method of discs are not available for deerhounds. The influence of sex or body weight (BW) on left ventricular diameter during diastole (LVDd) and systole (LVDs) has never been reported. OBJECTIVES: Prospectively determine ECHO RI and assess prevalence of dilated cardiomyopathy (DCM) in healthy UK deerhounds. ANIMALS: Ninety-nine deerhounds. METHODS: Deerhounds scored on ECHO and ECG variables then classified as normal (NORM), equivocal (EQUIV) or affected (AFF) with DCM. Fifty-nine NORM deerhounds used to determine ECHO RI. RESULTS: Prevalence of DCM was 21.6%. There were significant differences in BW (P<0.001), LVDd (P<0.001) and LVDs (P<0.05) between female and male deerhounds. Cut-off values for EDVI (≥140.2 mL/m2: 79% sensitivity/97% specificity), ESVI (≥71.9 mL/m2: 94.7% sensitivity/94.2% specificity) and EF (≤42.1%: 84.2% sensitivity/92.8% specificity) were proposed to help diagnose DCM. The most reliable ECHO variables to identify AFF dogs were LVDs indexed to BW by allometric scaling and ESVI; one of the least reliable was sphericity index. Ventricular arrhythmias (VA) were identified in 13.6% of the population, with the highest prevalence in AFF deerhounds (42%). CONCLUSIONS: Preclinical DCM in deerhounds is common and VA may be associated with DCM. Healthy deerhounds have higher LVDd, LVDs and EDVI compared with other breeds. This study provides ECHO RIs for deerhounds; sex or BW RIs should be used when screening.

Usefulness of cardiac biomarker screening to detect dilated cardiomyopathy in Dobermanns.

OBJECTIVES: To assess the diagnostic accuracy of two cardiac biomarker assays (N-terminal pro-BNP , Troponin I) in detecting dilated cardiomyopathy in Dobermanns. MATERIALS AND METHODS: Dobermanns undergoing cardiac biomarker testing were screened by echocardiography and Holter monitoring, then assigned to a group: normal, equivocal, arrhythmia form of dilated cardiomyopathy, echocardiographic form of dilated cardiomyopathy or both. Some were reassessed to identify final status. Initial cardiac biomarker results were compared to final status. Receiver operating characteristic curves were used to identify area under the curve and corresponding sensitivity (Se), specificity (Sp) for different cut-offs (CO) for each cardiac biomarker. RESULTS: A total of 118 Dobermanns with cardiac biomarker data had echocardiography/Holter assessment. Repeat assessment was carried out in 47 Dobermanns after 394.5 ±151.0 days. Seventeen dogs changed group between initial and final status. The final status of 59 was normal, nine were equivocal and 50 had dilated cardiomyopathy (prevalence 42.4%). Of the dilated cardiomyopathy group, 25 had dilated cardiomyopathy-both, 13 dilated cardiomyopathy-echocardiography and 12 dilated cardiomyopathy-Holter. Receiver operating characteristic area under the curve=0.807 for N-terminal proBNP (Se 0.69 and Sp 0.81) and 0.873 for high-sensitivity cardiac Troponin I (Se 0.77 and Sp 0.86). When both Se and Sp were optimised for all forms of dilated cardiomyopathy, N-terminal proBNP cut-off was 626 pmol/L (Se and Sp 0.79) and high-sensitivity cardiac Troponin I cut-off was 0.056 ng/mL (Se and Sp 0.84). Receiver operating characteristic area under the curve was higher for dilated cardiomyopathy-echocardiography (NT-proBNP 0.883; high-sensitivity cardiac Troponin I 0.907) than dilated cardiomyopathy-Holter. CLINICAL SIGNIFICANCE: Cardiac biomarker screening may be useful to select Dobermanns which would benefit from further assessment by echocardiography and Holter.

Low plasma taurine levels in English cocker spaniels diagnosed with dilated cardiomyopathy.

OBJECTIVES: The aims of this study were to evaluate taurine levels in English cocker spaniels with dilated cardiomyopathy and assess their survival time and natural progression of their disease. MATERIALS AND METHODS: Retrospective comparison of English cocker spaniels with dilated cardiomyopathy phenotype with and without taurine deficiency at the cardiology department of a UK academic referral centre between 2008 and 2018. RESULTS: Taurine plasma concentration was available in 16 English cocker spaniels with dilated cardiomyopathy phenotype; 13 of 16 had congestive heart failure and three of 16 did not. Taurine concentration was low (<50 µmol/L) in 13 of 16 and normal in three of 16. Deficient dogs received taurine supplementation in addition to conventional cardiac medications. Eight dogs were still alive at the end of this study and eight were dead. MST for all dogs included in the study was 2800 days. Left ventricular systolic function improved and left ventricular dimensions reduced in English cocker spaniels with taurine deficiency following taurine supplementation and conventional cardiac therapy, although similar results were observed in English cocker spaniels with normal taurine concentration on cardiac therapy alone. CLINICAL SIGNIFICANCE: Based on laboratory reference intervals, low taurine concentrations were common in English cocker spaniels with dilated cardiomyopathy, showing a possible association between dilated cardiomyopathy in English cocker spaniels and taurine deficiency; supplementation with taurine was not curative.

Mitral valve dysplasia in eight English Springer Spaniels.

INTRODUCTION: To describe the signalment, physical examination, and echocardiographic findings of a series of English Springer Spaniels (ESSs) diagnosed with congenital mitral valve dysplasia (MD). ANIMALS: Eight client-owned ESSs with congenital MD referred for murmur investigation and/or suspected congestive heart failure (CHF). MATERIALS AND METHODS: Retrospective case series. Medical records and echocardiograms were reviewed to collect relevant data. Echocardiograms were assessed for the following abnormalities consistent with MD: thickened valve leaflets or leaflet tips, a 'hockey stick' appearance to the valve leaflets, abnormal length of one leaflet with respect to the other, and tethering of one or both leaflets to the papillary muscles. RESULTS: All eight dogs showed the typical echocardiographic lesions associated with MD: thickened leaflet tips (5/8), 'hockey stick' appearance (5/8), elongated anterior leaflet (4/8), tethering of one or both leaflets (7/8). Seven of the eight dogs presented in CHF. Six of the eight dogs had left ventricular dilation in both systole and diastole. Two of the eight dogs had reduced systolic function as assessed by ejection fraction/fractional shortening; however end-systolic volume index was increased in 6/8 dogs. Two dogs subsequently developed atrial fibrillation. CONCLUSIONS: Congenital MD should be considered in ESSs with a left-sided apical systolic murmur, particularly in younger dogs. The valve changes seen are similar to those reported in other breeds with MD (thickened leaflet tips, hockey stick appearance to open leaflet tips, abnormal leaflet tethering, abnormally shaped leaflets) and may result in marked remodeling and CHF.

Preliminary investigation of serum cardiac troponin I in dogs with acute ischaemic stroke.

OBJECTIVES: To describe the incidence of elevated serum cardiac troponin I in dogs with acute ischaemic strokes, to evaluate its prognostic value in these patients and characterise a possible relationship between cardiac troponin I elevation in dogs with ischaemic strokes and underlying cardiac dysfunction. MATERIALS AND METHODS: Prospective study of 18 dogs with acute ischaemic stroke diagnosed by MRI of the brain. Serum cardiac troponin I concentration, trans-thoracic echocardiography and six-lead electrocardiography were performed and findings were compared between dogs with good and poor outcome. RESULTS: Serum cardiac troponin I was increased in 17 dogs (median 0.95 ng/mL; range 0.146 to 153). Focal hyperechoic regions of myocardium were visible in two dogs using trans-thoracic echocardiography and presumed to represent acute infarcts. A significant association was found between cardiac troponin I and creatinine concentrations. No difference in cardiac troponin I concentrations was detected between dogs that experienced good and poor outcomes. Clinically important cardiac dysfunction was identified in two dogs. CLINICAL SIGNIFICANCE: Cardiac troponin I is commonly elevated in patients diagnosed with acute ischaemic stroke but, in this small study population, did not have prognostic value. Larger studies (recruiting a study population of 98 dogs for a power of 0.8 and a 0.05 alpha/critical value) would aid in further investigation of these preliminary results.

The prevalence of pulmonary hypertension in Cavalier King Charles spaniels compared with other breeds with myxomatous mitral valve disease.

INTRODUCTION: Pulmonary hypertension (PH) is a common consequence of myxomatous mitral valve disease (MMVD). Cavalier King Charles spaniels (CKCS) are frequently affected with MMVD and appear to have different disease progression compared to other dogs. This study aimed to determine if CKCS are more likely to develop PH as a result of MMVD than dogs of other breeds. A secondary aim was to explore whether breed or PH impacted survival. ANIMALS: A total of 187 dogs diagnosed with MMVD, 94 CKCS and 93 non-CKCS, were included in this study. METHODS: This is a retrospective review of dogs with MMVD. Data were analyzed for presence of PH, congestive heart failure (CHF) and echocardiographic variables including the ratio between mitral E wave velocity (E vel) and isovolumic relaxation time (E/IVRT) and were compared between CKCS/non-CKCS and dogs with/without PH. Survival analysis was also performed. RESULTS: American College of Veterinary Internal Medicine (ACVIM) stage (p < 0.001), CKCS (p = 0.005), left atrium-to-aortic ratio (LA/Ao) (p < 0.001), E vel (p < 0.001) and log10(E/IVRT) (p < 0.001) were significant at the univariate level for PH development. At the multivariate level, only ACVIM stage remained significant (p = 0.044), suggesting that worsening MMVD was the predominant determinant of PH development in this study. Pulmonary hypertension was associated with greater likelihood of CHF (p < 0.001) and death (both cardiac [p < 0.001] and all-cause mortality [p = 0.011]). Cavalier King Charles spaniels were more likely to experience cardiac death than non-CKCS (p = 0.004). CONCLUSIONS: In this study, development of PH was associated with worse MMVD, according to ACVIM stage.

Usefulness of pulsed-wave tissue Doppler imaging at the mitral annulus for prediction of new-onset atrial fibrillation in dogs.

INTRODUCTION: The time from the onset of the P wave on electrocardiogram to the peak of late diastolic wave signal (PA-TDI interval) recorded by left atrial pulsed-wave tissue Doppler imaging (PW-TDI) is a surrogate of the total atrial conduction time, and it can predict the development of new-onset atrial fibrillation (AF) in people. This study investigated whether PA-TDI interval measured with PW-TDI at the level of lateral aspect of the mitral valve annulus could identify dogs which developed AF within 6 months after echocardiography. ANIMALS: Forty-two dogs with different cardiac diseases were included; 21 dogs developed AF within 6 months after echocardiography (AF group) and 21 dogs did not (non-AF group). Each AF case was matched with a non-AF case for body weight and left atrium:aortic root ratio. METHODS: This was a retrospective study. Review of signalment, underlying disease and echocardiography data were included. PA-TDI interval was measured offline from acquired PW-TDI images. PA-TDI interval and standard echocardiographic variables were compared between groups. Receiver operator characteristic curves were used to identify the best AF predictor. Univariate and multivariate regression were used to evaluate predictors of PA-TDI interval. RESULTS: The AF group had significantly greater 2D left atrial maximal diameter, left-ventricular (LV) end-diastolic volume, M-Mode LV internal diameter and LV end-systolic volume index. PA-TDI was significantly longer in the AF group, and it was superior to other echocardiographic variables in predicting AF development within 6 months (AUC = 0.896). CONCLUSIONS: PA-TDI interval measured with PW-TDI at the lateral mitral valve annulus may identify dogs at risk of developing AF.

Phenotypic description of cardiac findings in a population of Dogue de Bordeaux with an emphasis on atrial fibrillation.

The aim of this study was to describe the clinical phenotype of Dogue de Bordeaux (DdB) referred for cardiac investigation, with particular reference to the prevalence of atrial fibrillation and associated features. Review of canine medical records of two United Kingdom veterinary referral hospitals identified 64 DdB with available echocardiographic and electrocardiographic (ECG)/Holter data. Atrial fibrillation was documented in 25 (39%) dogs and supraventricular tachycardia was recorded in five (7.8%) dogs. In a subset of 34 dogs, excluding congenital heart disease (n=17), presence of a cardiac mass (n=7) and non-cardiac neoplasia (n=6), 19 (56%) dogs had atrial fibrillation, with a median heart rate of 200 beats per min (bpm) on presentation. Atrial fibrillation was inconsistently associated with cardiac chamber remodelling, but was frequently associated with systolic dysfunction (13/19, 68.4%) and right sided atrial or ventricular dilatation (14/19, 73.7%) in dogs with atrial fibrillation in this subset. No dogs in this subset had right sided atrial or ventricular dilatation in the absence of supraventricular arrhythmia or systolic dysfunction. The absence of structural heart disease in some dogs with supraventricular arrhythmias suggests that an underlying primary arrhythmic process might be responsible for initiating remodelling, although a primary cardiomyopathy cannot be ruled out.

White blood cell differentials in dogs with congestive heart failure (CHF) in comparison to those in dogs without cardiac disease.

OBJECTIVES: To determine if dogs with congestive heart failure have different white blood cell differential cell counts than dogs without cardiac disease. MATERIALS AND METHODS: In total, 72 dogs with congestive heart failure and 143 controls were included in this retrospective study. Signalment, white blood cell differential counts and echocardiography data were retrieved. Basic statistical analysis was performed on white blood cell differential counts, and principal component analysis was used to compare these counts between cases and controls, with age, gender and case/control status as supplementary variables. Cases and controls were compared with binary logistic regression for the principal components identified and individual white blood cell differential counts. Principal component analysis of cases alone was conducted with age, gender, weight and mitral E wave:isovolumic relaxation time as supplementary variables. Linear regression analysis was used to explore the association between mitral E wave:isovolumic relaxation time and the principal components, weight, gender, age and diagnosis (mitral valve disease or dilated cardiomyopathy). RESULTS: Among cases and controls, the largest variance in data (component 1) was associated with neutrophils, band neutrophils, monocytes and case status (P<0·01). The odds of an individual being a case increased 2·5-fold (95% confidence interval: 1·4 to 4·4) for each unit increase in component 1. Among the cases, mitral E wave:isovolumic relaxation time was associated with neutrophil count and case/control category. CLINICAL SIGNIFICANCE: Dogs with congestive heart failure had a statistically significant increase in neutrophils, band neutrophils and monocytes in comparison with those without cardiac disease but the cell counts remained within normal reference intervals.

Retrospective Evaluation of the Effect of Heart Rate on Survival in Dogs with Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) usually is associated with a rapid ventricular rate. The optimal heart rate (HR) during AF is unknown. HYPOTHESIS/OBJECTIVES: Heart rate affects survival in dogs with chronic AF. ANIMALS: Forty-six dogs with AF and 24-hour ambulatory recordings were evaluated. METHODS: Retrospective study. Holter-derived HR variables were analyzed as follows: mean HR (meanHR, 24-hour average), minimum HR (minHR, 1-minute average), maximum HR (maxHR, 1-minute average). Survival times were recorded from the time of presumed adequate rate control. The primary endpoint was all-cause mortality. Cox proportional hazards analysis identified variables independently associated with survival; Kaplan-Meier survival analysis estimated the median survival time of dogs with meanHR <125 bpm versus ≥125 bpm. RESULTS: All 46 dogs had structural heart disease; 31 of 46 had congestive heart failure (CHF), 44 of 46 received antiarrhythmic drugs. Of 15 dogs with cardiac death, 14 had CHF. Median time to all-cause death was 524 days (Interquartile range (IQR), 76-1,037 days). MeanHR was 125 bpm (range, 62-203 bpm), minHR was 82 bpm (range, 37-163 bpm), maxHR was 217 bpm (range, 126-307 bpm). These were significantly correlated with all-cause and cardiac-related mortality. For every 10 bpm increase in meanHR, the risk of all-cause mortality increased by 35% (hazard ratio, 1.35; 95% CI, 1.17-1.55; P < 0.001). Median survival time of dogs with meanHR<125 bpm (n = 23) was significantly longer (1,037 days; range, 524-open) than meanHR ≥125 bpm (n = 23; 105 days; range, 67-267 days; P = 0.0012). Mean HR was independently associated with all-cause and cardiovascular mortality (P < 0.003). CONCLUSIONS AND CLINICAL IMPORTANCE: Holter-derived meanHR affects survival in dogs with AF. Dogs with meanHR <125 bpm lived longer than those with meanHR ≥ 125 bpm.

European Society of Veterinary Cardiology screening guidelines for dilated cardiomyopathy in Doberman Pinschers.

BACKGROUND: Dilated cardiomyopathy (DCM) is the most common cardiac disease in large breed dogs and is inherited in Doberman Pinschers with a high prevalence (58%). OBJECTIVE: The European Society for Veterinary Cardiology convened a task force to formulate screening guidelines for DCM in Dobermans. RECOMMENDATIONS: Screening for occult DCM in Dobermans should start at three years of age and use both Holter monitoring and echocardiography. Yearly screening over the life of the dog is recommended, as a one-time screening is not sufficient to rule out future development of DCM. The preferred echocardiographic method is the measurement of the left ventricular volume by Simpson's method of discs (SMOD). Less than 50 single ventricular premature complexes (VPCs) in 24 h are considered to be normal in Dobermans, although detection of any number of VPCs is cause for concern. Greater than 300 VPCs in 24 h or two subsequent recordings within a year showing between 50 and 300 VPCs in 24 h is considered diagnostic of occult DCM in Dobermans regardless of the concurrent echocardiographic findings. The guidelines also provide recommendations concerning ancillary tests, that are not included in the standard screening protocol, but which may have some utility when recommended tests are not available or financially untenable on an annual basis. These tests include assay of cardiac biomarkers (Troponin I and N-Terminal pro-B-type Natriuretic Peptide) as well as a 5-min resting electrocardiogram (ECG). CONCLUSION: The current guidelines should help to establish an early diagnosis of DCM in Dobermans.

Assessment of left ventricular function in healthy Great Danes and in Great Danes with dilated cardiomyopathy using speckle tracking echocardiography.

OBJECTIVES: Assess global circumferential and radial systolic and diastolic myocardial function with speckle tracking echocardiography (STE) in healthy Great Danes (GD) and in GD diagnosed with dilated cardiomyopathy (DCM). ANIMALS: Eighty-nine GD were included in the study: 39 healthy (normal group [NORMg]) and 50 diagnosed with DCM (DCMg). METHODS: This was a retrospective study. Signalment and echocardiographic diagnosis were obtained from the medical records of GD assessed between 2008 and 2012. Speckle tracking echocardiography analysis of circumferential (C) and radial (R) strain (St) and strain rate (SR) in systole (S), early (E) and late (A) diastole was performed at the levels of the mitral valve (MV), papillary muscles (PM) and apex (Ap) of the left ventricle. Univariable and multivariable analysis was performed to identify differences between groups. RESULTS: Speckle tracking echocardiography variables increase from the MV towards the Ap of the left ventricle in both NORMg and DCMg dogs, some reaching statistical significance. Most of the variables (28/31) were lower in DCMg than in NORMg dogs: statistically significant variables included radial SR at the Ap in systole (p=0.029), radial strain at the PM (p=0.012), circumferential SR at the PM in systole (p=0.031), circumferential and radial SR at the MV in early diastole (p=0.019 and p=0.049, respectively). CONCLUSIONS: There are significant differences in STE variables between NORMg and DCMg Great Danes, although the overlap between the two groups may indicate that these variables are not sufficiently discriminatory. STE variables are not sufficiently sensitive to use in isolation as a screening method.

A descriptive review of cardiac tumours in dogs and cats.

Cardiac tumours are uncommon in the canine and feline population and often an incidental finding. Common types include haemangiosarcoma (HSA), aortic body tumours (chemodectoma and paraganglioma) and lymphoma. These neoplasms can cause mild to severe, life-threatening clinical signs that are independent of the histological type and may be related to altered cardiovascular function or local haemorrhage/effusion into the pericardial space. Cardiac tumours may require symptomatic treatment aimed at controlling tumour bleeding and potential arrhythmias, and other signs caused by the mass effect. Additional treatment options include surgery, chemotherapy and radiotherapy. For all medical therapies, complete remission is unlikely and medical management, beyond adjunctive chemotherapy in HSA, requires further investigation but combination chemotherapy is recommended for lymphoma. The aim of this report is to summarize and critically appraise the current literature in a descriptive review. However, interpretation is limited by the lack of definitive diagnosis and retrospective nature of most studies.

Serum cardiac troponin I in canine syncope and seizures.

OBJECTIVE: To determine if serum cardiac troponin I (cTnI) concentration distinguishes between cardiogenic syncope and collapsing dogs presenting with either generalized epileptic seizures (both with and without cardiac disease) or vasovagal syncope. ANIMALS: Seventy-nine prospectively recruited dogs, grouped according to aetiology of collapse: generalized epileptic seizures (group E), cardiogenic syncope (group C), dogs with both epileptic seizures and cardiac disease (group B), vasovagal syncope (group V) or unclassified (group U). METHODS: Most patients had ECG (n = 78), echocardiography (n = 78) and BP measurement (n = 74) performed. Dogs with a history of intoxications, trauma, evidence of metabolic disorders or renal insufficiency (based on serum creatinine concentrations >150 µmol/L and urine specific gravity <1.030) were excluded. Serum cTnI concentrations were measured and compared between groups using non-parametric statistical methods. Multivariable regression analysis investigated factors associated with cTnI. Receiver operator characteristic curve analysis examined whether cTnI could identify cardiogenic syncope. RESULTS: Median cTnI concentrations were higher in group C than E (cTnI: 0.165 [0.02-27.41] vs. 0.03 [0.01-1.92] ng/mL; p<0.05). Regression analysis found that serum cTnI concentrations decreased with increasing time from collapse (p=0.015) and increased with increasing creatinine concentration (p=0.028). Serum cTnI diagnosed cardiogenic syncope with a sensitivity of 75% and specificity of 80%. CONCLUSIONS: Serum cTnI concentrations were significantly different between groups C and E. However, due to the overlap in cTnI concentrations between groups cTnI, measurement in an individual is not optimally discriminatory to differentiate cardiogenic syncope from collapse with generalized epileptic seizures (both with and without cardiac disease) or vasovagal syncope.