Serum microRNA profiles in cats with hypertrophic cardiomyopathy.

The role of microRNAs (miRNAs) in the pathogenesis of heart diseases of humans and rodents, as well as their diagnostic potential, has recently received much attention, but comparable studies for spontaneous disease models in the domestic cat are missing. Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats. The pathology is largely unknown, but is suspected to be influenced by genetic background. In this study, we examined the miRNA profiles in the serum of cats with stable congestive heart failure caused by HCM (n = 11) and healthy control cats (n = 12) using miRNA arrays. 965 out of 2026 miRNAs could be detected in at least six samples of either of the groups. Eleven mammalian miRNAs were differentially expressed between the groups with a fold change ≥ 1.6. Hierarchical cluster analysis resulted in distinct separation of the two groups. After correction for multiple testing (adjusted p < 0.05), a higher expression of miR-381-3p, miR-486-3p, miR-4751, miR-476c-3p, miR-5700, miR-513a-3p, and miR-320e in the HCM group was confirmed. Additionally, miR-1246 was found to be upregulated 3-fold in the HCM group using quantitative RT-PCR. Software analysis of the significantly regulated miRNAs revealed 49 mRNA targets involved in cardiac hypertrophy. Cats with primary HCM show a distinct miRNA profile that includes miRNAs that have already been shown to be differentially regulated in human patients and rodent models for cardiac disease. Studying HCM as a spontaneous cardiac disease of the cat may help to reveal additional pathophysiologic pathways.

Reference intervals for various measurements of canine left atrial size and function obtained using two-dimensional and three-dimensional echocardiography.

BACKGROUND: Many canine cardiac diseases are associated with left atrial (LA) remodeling and decreased function. For accurate assessment of LA indices, large-scale and prospectively determined reference intervals are necessary. OBJECTIVES: To generate reference intervals of LA size and function using two-dimensional and three-dimensional echocardiography. ANIMALS: Two hundred and one healthy adult dogs. METHODS: Left atrial volume was assessed in right parasternal long-axis, left apical four-chamber and two-chamber views using monoplane Simpson's method, two-dimensional and three-dimensional speckle tracking. Additionally, LA diameter was measured in right parasternal short-axis and long-axis views. Furthermore, LA function was determined by measuring strain and calculating LA fractional shortening and ejection fraction. All variables were tested for correlation to heart rate, age, and body weight. For LA diameter and volume, scaling exponents and prediction intervals were generated using allometric scaling. Reference intervals for LA function parameters were calculated using nonparametric methods. RESULTS: Left atrial diameter and volume showed a strong correlation with body weight. The scaling exponent for LA diameter was approximately 1/3 (0.34-0.40) and approximately one for volume measurements (0.97-1.26). Parameters of LA function showed no clinically relevant correlation with body weight, except for two variables, which showed a mild negative correlation. No clinically relevant correlations with age or heart rate were found. CONCLUSIONS: Reference intervals for linear, two-dimensional and three-dimensional measurements of LA size and function were established. The wide range of measurement methods offers the opportunity to select the appropriate reference values for LA evaluation depending on the available technical possibilities.

Two-dimensional speckle tracking-derived global longitudinal strain in healthy Doberman Pinschers: method evaluation, variability, and reference values.

INTRODUCTION: Evaluation of two-dimensional speckle tracking (2D-ST)-derived global longitudinal strain (GLS) in healthy Doberman Pinschers (DP) is essential before it can be used in diseased DP to assess systolic function. To determine feasibility and observer related measurement variability of 2D-ST-derived GLS by use of AutoSTRAIN (AUTO) and 2D Cardiac Performance Analysis (TomTec Imaging Systems GmbH, Unterschleissheim, Germany). ANIMALS, MATERIALS, AND METHODS: This prospective study included 120 healthy, client-owned DP presented for screening evaluation. Global longitudinal strain of the apical four- (GLSA4C), two-, and three-chamber view as well as the average GLS of all three views combined (GLSAV) were determined, compared, and reference values established. Measurement variability was assessed by using intra- and inter-observer coefficient of variation. RESULTS: A small difference existed for GLSAV (mean + 0.23%; P=0.022) between the two software programs although the determined strain values were similar and positively correlated (r = 0.84; P<0.001). No difference could be found between GLSAV and GLSA4C for AUTO (mean + 0.16%; P=0.228), whereas a difference existed for Cardiac Performance Analysis (mean -0.89% (end-systolic strain) and -0.56% (peak strain), P<0.0001). Software specific reference values were established for GLSAV and GLSA4C. Intra- and inter-observer coefficient of variation revealed very low to low measurement variability, with better results for AUTO. DISCUSSION AND CONCLUSIONS: Two-dimensional speckle tracking (2D-ST) derived GLS is a feasible technique to assess systolic function with low measurement variability. Whenever possible, GLSAV should be determined, although GLSA4C might be a potential alternative.

Systolic function in dogs with pulmonic stenosis of different severities and the effect of balloon valvuloplasty.

INTRODUCTION/OBJECTIVES: Pulmonic stenosis (PS) is one of the most common congenital heart diseases in dogs leading to right ventricular (RV) pressure overload, myocardial remodeling, and potential RV dysfunction. Our objectives were to investigate the extent of RV systolic dysfunction in canine PS and to examine the immediate influence of balloon valvuloplasty (BV) on systolic function. ANIMALS, MATERIALS AND METHODS: This prospective study evaluated 72 dogs with PS and 86 healthy dogs. Echocardiographic parameters of systolic function included normalized tricuspid annular plane systolic excursion (N-TAPSE), normalized systolic myocardial tissue Doppler velocity of the lateral tricuspid annulus (N-RVFW-S'), fractional area change, and speckle-tracking longitudinal endocardial RV strain. Forty-four dogs underwent BV and were re-examined after surgery. RESULTS: Systolic function at the basal segment of the RV was significantly lower in the PS group when compared to healthy dogs (mean N-TAPSE 4.29 ± standard deviation 1.18 mm/kg0.285 vs. 5.60 ± 1.29 mm/kg0.285; median N-RVFW-S' 5.28 [lower-upper 25% quantile 4.35-6.43 cm/s/kg0.186] vs. 7.82 [6.73-8.79 cm/s/kg0.186]; all P<0.001). Global longitudinal RV endocardial strain showed no significant difference between the two groups (-28.50 ± 6.23% vs. 28.61 ± 4.64%; P=0.886), but segmental strain analyses revealed basal hypo- and potential compensatory hyperkinesis of the apical RVFW. Furthermore, BV affected most parameters of systolic function, but not the segmental strain values and N-TAPSE. CONCLUSIONS: Right ventricular basal longitudinal systolic function is decreased in dogs with PS in comparison to a healthy cohort. Regional and global function does not necessarily coincide.

[Pericardial effusion in a cat with feline infectious peritonitis]. / Perikarderguss bei einer Katze mit feliner infektiöser Peritonitis.

This case report describes the disease progression of a male cat with pericardial effusion. Clinical signs (dyspnea, lethargy, and weakness) started very acutely. The initial laboratory profile showed only an increase in alanine aminotransferase enzyme activity. Diagnostic imaging revealed pericardial effusion. Effusion analysis showed a Rivalta-positive, modified transudate. Detection of feline coronavirus antigen in macrophages was negative. General condition and laboratory parameters dramatically worsened within seven days. Therefore, the owners decided to euthanize the cat. Even if effusion variables are macroscopically and microscopically suspicious for FIP, a definitive diagnosis of FIP could only be made by histology (including immunhistochemical staining).

Screening for dilated cardiomyopathy in dogs.

BACKGROUND: Dilated cardiomyopathy (DCM) is the most common cardiac disease in large breed dogs. The disease can start with arrhythmias or with systolic dysfunction of the myocardium. OBJECTIVE: To describe screening methods for DCM in various breeds and provide a new, modified staging system. RECOMMENDATIONS: Screening for occult DCM should start at three years of age and use Holter monitoring in Boxers and Dobermans and might be useful also in other breeds. Single ventricular premature complexes (VPCs) can be detected in many healthy dogs, but healthy animals typically have <50 VPCs in 24 h and demonstrate minimal complexity most often occurring only as single ectopic beats. In general, >100 VPCs in 24 h was recommended as the cut-off value for establishing a diagnosis of DCM. However, there are breed-specific recommendations related to Holter recording diagnosis of DCM in Dobermans and Boxers. Yearly screening over the life of a dog is recommended, as a one-time screening is not sufficient to rule out the future development of DCM. Several echocardiographic methods such as M-mode derived measurements, the measurement of the left ventricular (LV) volume by Simpson's method of discs (SMOD), and E-point to septal separation (EPSS) are recommended for screening purposes. The value of additional tests such as cardiac biomarkers (troponin I and N-terminal pro-B-type natriuretic peptide) as well as a 5-min resting electrocardiogram (ECG) or newer echocardiographic methods such as strain measurements is discussed. CONCLUSION: This review suggests some guidelines for screening for DCM in various breeds.

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.

[Measuring myocardial velocity using tissue Doppler imaging in healthy dogs]. / Messung der myokardialen Geschwindigkeit mittels Gewebe-Doppler beim gesunden Hund.

OBJECTIVE: of the study was to evaluate tissue velocity imaging (TVI) with respect to its reproducibility and to introduce reference values in a large canine population. In addition, the influence of gender, heart rate, age, weight and breed of the dogs was evaluated. MATERIAL AND METHODS: A total of 199 healthy dogs were included. The longitudinal TVI was recorded from an apical four-chamber view using colour Doppler technique in unsedated dogs. Each myocardial wall was recorded as a single wall image, aligning the ultrasound beam as parallel as possible to the longitudinal motion of the respective wall. Off-line analysis was performed using the Q-analysis software. RESULTS: Coefficients of variance for intrareader and interreader variability for each parameter were less than 10.0% and 12.4%, respectively. Tissue velocities were heterogeneously distributed within the myocardium, demonstrating an apico-basal gradient. Whereas gender did not influence TVI variables, heart rate, age, breed and weight had a significant influence on the tissue velocity. CONCLUSION AND CLINICAL RELEVANCE: TVI is a sophisticated and promising echocardiographic technique. It is relatively easy to perform and can be included in the evaluation of systolic and diastolic myocardial function in routine daily practice. One limitation is that it is influenced by heart rate, age, breed and weight of the dogs. This study provides a basis for further investigation on this topic and supplies reference values for different weight groups in dogs.

Comparison of pulsed wave and color Doppler myocardial velocity imaging in healthy dogs.

BACKGROUND: Tissue velocity imaging (TVI) is increasingly used in small animal cardiology. Tissue velocity of the myocardial wall can be measured by pulsed wave (PW) or color Doppler (CD) imaging methods. Currently, the same reference ranges are used for PW TVI and CD TVI methods. However, if and how both methods correlate, and whether they can be used interchangeably, have not been assessed in small animals. OBJECTIVES: To compare the results of PW TVI and CD TVI measurements. ANIMALS: Seventy-one healthy dogs. METHODS: Longitudinal myocardial velocity profiles were recorded from the 4-chamber left apical view. Peak maximal systolic (S), early (E), and late diastolic (A) velocities were measured off-line in a blinded fashion in the septal and lateral left ventricular wall by PW TVI and CD TVI. Differences between peak PW TVI and CD TVI waves were analyzed by a paired t-test. Regression analysis and Bland-Altman difference plots also were used to assess agreement between methods. RESULTS: There was a significant correlation between PW TVI and CD TVI (P < .001). However, S, E, and A waves measured by PW TVI were significantly higher than the CD TVI values (P < .001). Peak systolic and diastolic PW velocities were approximately 2.20 cm/s higher than corresponding mean CD TVI velocities. CONCLUSIONS AND CLINICAL IMPORTANCE: PW TVI measurements are significantly higher compared with CD TVI measurements. Theses differences are clinically relevant. These methods should not be used interchangeably, and different reference ranges for PW TVI and CD TVI should be used.

Ability of a 5-minute electrocardiography (ECG) for predicting arrhythmias in Doberman Pinschers with cardiomyopathy in comparison with a 24-hour ambulatory ECG.

BACKGROUND: Ventricular premature contractions (VPCs) are common in the occult stage of cardiomyopathy in Doberman Pinschers. Although the gold standard for detecting arrhythmia is the 24-hour ambulatory electrocardiography (ECG) (Holter), this method is more expensive, time-consuming and often not as readily available as common ECG. OBJECTIVES: Comparison of 5-minute ECGs with Holter examinations. ANIMALS: Eight hundred and seventy-five 5-minute ECGs and Holter examinations of 431 Doberman Pinschers. METHODS: Each examination included a 5-minute ECG and Holter examination. A cut-off value of > 100 VPCs/24 hours using Holter was considered diagnostic for the presence of cardiomyopathy. Statistical evaluation included calculation of sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: Holter examinations revealed > 100 VPCs/24 hours in 204/875 examinations. At least 1 VPC during a 5-minute ECG was detected in 131 (64.2%) of these 204 examinations. No VPCs were found in the 5-minute ECG in 73 (35.8%) examinations of affected Doberman Pinschers. A 5-minute ECG with at least 1 VPC as cut-off had a sensitivity of 64.2%, a specificity of 96.7%, a positive predictive value of 85.6% and a negative predictive value of 89.9% for the presence of > 100 VPCs/24 hours. CONCLUSIONS AND CLINICAL IMPORTANCE: A 5-minute ECG is a rather insensitive method for detecting arrhythmias in Doberman Pinschers. However, the occurrence of at least 1 VPC in 5 minutes strongly warrants further examination of the dog, because specificity (96.7%) and positive predictive value (85.6%) are high and could suggest occult cardiomyopathy.

Use of Simpson's method of disc to detect early echocardiographic changes in Doberman Pinschers with dilated cardiomyopathy.

BACKGROUND: M-mode is the echocardiographic gold standard to diagnose dilated cardiomyopathy (DCM) in dogs, whereas Simpson's method of discs (SMOD) is the preferred method to detect echocardiographic evidence of disease in humans. OBJECTIVES: To establish reference values for SMOD and to compare those with M-mode measurements. ANIMALS: Nine hundred and sixty-nine examinations of 471 Doberman Pinschers. METHODS: Using a prospective longitudinal study design. Reference values for SMOD were established using 75 healthy Doberman Pinschers >8 years old with <50 ventricular premature contractions (VPCs) in 24 hours. The ability of the new SMOD cut-off values, normalized to body surface area (BSA), for left ventricular end-diastolic volume (LVEDV/BSA >95mL/m(2) ) and end-systolic volume (LVESV/BSA > 55mL/m(2) ) to detect echocardiographic changes in Doberman Pinschers with DCM was compared with currently recommended M-mode values. Dogs with elevated SMOD values but normal M-mode measurements were followed-up using a prospective longitudinal study design. RESULTS: At the final examination 175 dogs were diagnosed with DCM according to both methods (M-mode and SMOD). At previous examinations, M-mode values were abnormal in 142 examinations only, whereas all 175 SMOD already had detected changes. Additionally, 19 of 154 dogs with >100 VPCs/24 hours and normal M-mode values had abnormal SMOD measurement. Six dogs with increased SMOD measurements remained healthy at several follow-up examinations (classified as false positive); in 24 dogs with increased SMOD measurements, no follow-up examinations were available (classified as unclear). CONCLUSIONS AND CLINICAL IMPORTANCE: SMOD measurements are superior to M-mode to detect early echocardiographic changes in Dobermans with occult DCM.

Assessment of left ventricular systolic function by strain imaging echocardiography in various stages of feline hypertrophic cardiomyopathy.

BACKGROUND: Diastolic dysfunction occurs in many cats with hypertrophic cardiomyopathy (HCM). Less is known about systolic function in various stages of HCM. Myocardial strain analysis by tissue Doppler imaging (TDI) is a noninvasive echocardiographic method to assess systolic function that has not been reported previously in cats. OBJECTIVES: To evaluate systolic function in various stages of feline HCM by measurement of myocardial strain. ANIMALS: Two hundred and sixty-three cats. METHODS: Cats were classified by echocardiography into one of the following groups: clinically healthy (control) group (n=160), mild HCM (n=22), moderate HCM (n=39), and severe HCM (n=42). Peak myocardial strain, measured by TDI in the basal and midventricular segment of the interventricular septal wall (IVS) and the left ventricular posterior wall (LVPW), was compared among different HCM and control groups. RESULTS: Whereas conventional echocardiography demonstrated an apparently normal or supernormal contractile state based on percentage of fractional shortening, myocardial strain in all HCM groups was significantly decreased compared with the control group (P<.001). There was a significant correlation between strain values and wall thickness (P<.001). Reproducibility of strain analysis was 6.3% in the IVS and 9.7% in the LVPW. CONCLUSIONS AND CLINICAL IMPORTANCE: Myocardial strain analysis is a new, valuable, and reproducible method in cats. This method allows noninvasive detection of abnormal systolic deformation in cats with HCM despite apparently normal left ventricular systolic function as assessed by conventional echocardiography. The abnormal systolic deformation already was present in mild HCM and increased with progressive left ventricular concentric hypertrophy.

Cardiac troponin I in Doberman Pinschers with cardiomyopathy.

BACKGROUND: Cardiac troponin I (cTnI) is useful for detection of cardiac myocyte damage, but its efficacy in detecting various stages of dilated cardiomyopathy (DCM) in Doberman Pinschers is unclear. OBJECTIVES: To evaluate the diagnostic value of cTnI in various stages of DCM in Dobermans. ANIMALS: Six hundred and fifty-three cTnI measurements of 336 Doberman Pinschers. METHODS: Using a longitudinal study design, staging of the disease was based upon 24-hour-ambulatory-ECG (Holter) and echocardiography. A total of 447 cTnI measurements were performed in 264 healthy Dobermans, and 206 cTnI measurements in 75 Dobermans with cardiomyopathy. Eighty-eight cTnI samples were from dogs with >100 ventricular premature contractions (VPCs)/24 hour, but without echocardiographic changes ("VPC group"). Additional 19 samples originated from dogs with only echocardiographic changes ("ECHO group"), and 56 samples from dogs with both VPCs and echocardiographic changes ("VPC plus ECHO group"). Twenty samples were from dogs with clinical signs ("clinical group"). The group "incipient" included 23 dogs, that were considered to be normal according to Holter and echocardiography at the time of the exam, but that developed DCM within 1.5 years. RESULTS: cTnI values of dogs in all disease groups, including the "incipient" (0.30+/-0.20) and "VPC group" (0.36+/-0.34), were significantly (P=.04, P<.001) higher than the control group (0.07+/-0.16). A cut-off value of >0.22 ng/mL had a sensitivity of 79.5% and a specificity of 84.4% to detect all forms of cardiomyopathy. CONCLUSIONS AND CLINICAL IMPORTANCE: cTnI measurement is a valuable diagnostic test that can detect cardiomyopathy in dogs that are otherwise clinically normal.

Association of A31P and A74T polymorphisms in the myosin binding protein C3 gene and hypertrophic cardiomyopathy in Maine Coon and other breed cats.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is an inherited autosomal dominant trait in cats. The A31P single nucleotide polymorphism (SNP) in the myosin binding protein C 3 gene is thought to be the causative mutation in Maine Coon cats. Additionally, the A74T SNP is offered as a genetic test for HCM. OBJECTIVES: To evaluate the genetic association between the above-mentioned SNPs and phenotypes. ANIMALS: Eighty-three Maine Coon cats and 68 cats of other breeds. METHODS: The study was performed prospectively. Cats were phenotyped as healthy or HCM with echocardiography. Taqman genotyping assays were used for genotyping; results were confirmed by sequencing analysis. RESULTS: A31P was found in 18/83 (22%) Maine Coon cats. Fifteen of 18 Maine Coons (83%) with the A31P mutation were healthy on echocardiographic examination (mean age 65 months). A74T was present in 28/79 (35%) of Maine Coons and in 42/68 (62%) of other cat breeds. Twenty-two of 28 (79%) of Maine Coons and 21/42 (62%) of other breed cats with the A74T mutation were healthy at a mean age of 72 months and 91 months, respectively. Of 12 Maine Coons with HCM, 9 (75%) were genotype-negative for A31P and 6 (50%) for A74T. Allele frequencies did not differ significantly (P= .47) between phenotype groups. None of the evaluated genetic tests was able to provide useful predictive information of disease outcome. CONCLUSIONS AND CLINICAL IMPORTANCE: The value of currently available genetic tests is low in the cats of this study. The mutations analyzed appear to have a low penetrance, and even homozygote cats can remain healthy.

Prevalence of dilated cardiomyopathy in Doberman Pinschers in various age groups.

BACKGROUND: Dilated cardiomyopathy (DCM) in Doberman Pinschers is an autosomal dominant inherited disease. The prevalence of DCM in Doberman Pinschers of various age groups in Europe is currently unknown, but this information would be important to develop recommendations for screening programs. OBJECTIVES: To evaluate the prevalence of cardiomyopathy in various age groups of Dobermans. ANIMALS: Seven hundred and seventy-five examinations in 412 Doberman Pinschers. METHODS: Dogs were included in a prospective longitudinal cohort study. Each examination included echocardiography and 24-hour ECG (Holter) examination. A cut-off value of >100 ventricular premature contractions (VPCs) per 24 hours on Holter examination or abnormal echocardiography was considered diagnostic for cardiomyopathy. The cumulative prevalence included all dogs with DCM and healthy dogs >7 years of age. RESULTS: DCM prevalence in various age groups was as follows: age group 1 (1 to <2 years) 3.3%, age group 2 (2 to <4 years) 9.9%, age group 3 (4 to <6 years) 12.5%, age group 4 (6 to <8 years) 43.6%, and age group 5 (>8 years) 44.1%. The cumulative prevalence of Doberman Pinscher cardiomyopathy was 58.2%. There was an equal sex distribution, but male dogs showed earlier echocardiographic changes than did female dogs, which had significantly more VPCs. CONCLUSIONS AND CLINICAL IMPORTANCE: The prevalence of Doberman cardiomyopathy is very high in Europe. Disease manifestation and progression are different between male and female dogs. Yearly screening for DCM by Holter examination and echocardiography is recommended, starting at 2 years of age.

[Left ventricular hypertrophy in the cat - "when hypertrophic cardiomyopathy is not hypertrophic cardiomyopathy"]. / Linksherzhypertrophie bei der Katze - <>

According to WHO classification hypertrophic cardiomyopathy (HCM) is a primary genetic cardiomyopathy. Echocardiographically HCM is characterized by symmetric, asymmetric or focal left ventricular hypertrophy (LVH) without recognizable underlying physical cause. However, echocardiographically HCM in cats may not be distinguishable from other causes of a thick appearing left ventricle. Hypovolemia can look like a hypertrophied ventricle but is basically only pseudohypertrophic. Well recognized and logical physical causes of LVH include systemic hypertension and outflow obstruction. LVH similar to HCM may also be found in feline hyperthyroidism. The context of the disease helps to differentiate these physical / physiological causes of LVH. Difficult to distinguish from HCM, particularly when based on a snapshot of a single echocardiographic exam, are myocarditis and <>. Only the clinical and echocardiographic course allow a reasonably confident etiological diagnosis and the differentiation between HCM and secondary LVH.

The prevalence of atrial premature complexes in healthy Doberman Pinschers and their role in the diagnosis of occult dilated cardiomyopathy.

The importance of atrial premature complexes (APCs) as a possible marker of occult dilated cardiomyopathy (DCM) in Doberman Pinschers (DP) is unknown. The aim of this study was to identify APC in healthy DP and to investigate their role as early markers of occult DCM. Holter-ECG results from 561 examinations of 153 DP at different time points were retrospectively evaluated, with special emphasis on APCs. Holter results from 110 healthy control DPs were compared to the last normal Holter and echocardiographic examinations in 43 DP that subsequently developed DCM within 15 months (DCM group), and to the first examination in the DCM group that contained ventricular premature complexes (VPC). There were no significant differences in the number of APCs or the coupling interval between the control group and the last normal examination in the DCM group (P > 0.05). The number of APCs increased slightly at the first abnormal examination in the DCM group. Healthy male DP had more APCs than females (P = 0.009) and older dogs had APCs more frequently than younger dogs (P < 0.001). About 85% of healthy DP with at least one APC/24 h had <20 APCs/24 h. Extracardiac diseases, especially gastrointestinal diseases influenced the occurrence of APCs (P = 0.037 and P = 0.006, respectively). APCs were present without obvious cardiac disease and were not a marker for the development of DCM, as they were not identified until after VPCs were present.

The role of atrial fibrillation as a prognostic factor in doberman pinschers with dilated cardiomyopathy and congestive heart failure.

Atrial fibrillation (AF) in congestive heart failure (CHF) is associated with a high risk of mortality and shorter survival times in human and veterinary medicine. A retrospective review of medical records was performed to evaluate the impact of AF on survival times in Doberman Pinschers with dilated cardiomyopathy (DCM). Time of first onset of CHF and its role as a prognostic factor were also determined, as were predictors of AF development. Forty-eight client-owned purebred Doberman Pinschers with DCM and CHF were included; 23 dogs presented with AF and 25 dogs did not develop AF until immediately before cardiac-related death. Dogs with AF survived for significantly shorter times than those without AF (P = 0.043). For dogs with AF, mean and median survival times were 88.2 days and 22 days, respectively (range, 42.1-134.4 days); mean and median survival times for dogs without AF were 150.7 days and 98 days, respectively (range, 98.5-203 days). AF increased the risk of cardiac-related death (hazard ratio [HR], 2.371; 95% confidence intervals [CI], 1.14-4.95; P = 0.021). Biventricular and right atrial dilation was only present in dogs with AF and right atrial enlargement was the only significant predictor of AF after multivariate analysis (P < 0.001). Dogs with AF had significantly higher mean heart rates than dogs without AF (201 beats per min [bpm] vs. 132 bpm; P < 0.001). In conclusion, AF in Doberman Pinschers with DCM and CHF increased the risk of cardiac-related death and reduced survival time.

Evaluation of a sensitive cardiac troponin I assay as a screening test for the diagnosis of hypertrophic cardiomyopathy in cats.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the most common cardiac disease in cats. However, most cats are not diagnosed until they develop congestive heart failure, arterial thromboembolism (ATE), or sudden cardiac death. Thus, an affordable screening test for early detection of HCM is desirable. HYPOTHESIS/OBJECTIVES: Evaluation of a sensitive cardiac troponin I (cTnI) assay as a screening test for HCM in cats and determination of a cutoff for its early detection. ANIMALS: One hundred sixty-six client-owned cats (male, n = 97) of various breeds were evaluated and classified using echocardiography as being healthy (n = 87), equivocal (n = 15), or having HCM (mild, n = 16; moderate, n = 10; severe, n = 34) or ATE (n = 4). METHODS: All cats were prospectively evaluated by echocardiography, and serum cTnI concentration was determined using the currently most sensitive assay (Siemens ADVIA Centaur TnI-Ultra). RESULTS: The median cTnI concentration was significantly different between study groups (P < .000001). A cutoff of 0.06 ng/mL provided good discrimination between healthy cats and cats with HCM (sensitivity, 91.7%; specificity, 95.4%; area under the curve [AUC], 0.95; 95% confidence interval [CI], 0.899-0.978). Even for asymptomatic cats with HCM, sensitivity and specificity for a cutoff of >0.06 ng/mL remained high at 87.8% and 95.4%, respectively (AUC, 0.93; 95% CI, 0.864-0.964). CONCLUSIONS AND CLINICAL IMPORTANCE: Cardiac troponin I can be used as a sensitive and specific screening test for the diagnosis of HCM in otherwise healthy cats (cutoff, >0.06 ng/mL). However, echocardiography is needed to confirm the diagnosis.

Effect of pimobendan or benazepril hydrochloride on survival times in dogs with congestive heart failure caused by naturally occurring myxomatous mitral valve disease: the QUEST study.

BACKGROUND: Myxomatous mitral valve disease (MMVD) continues to be an important cause of morbidity and mortality in geriatric dogs despite conventional therapy. HYPOTHESIS: Pimobendan in addition to conventional therapy will extend time to sudden cardiac death, euthanasia for cardiac reasons, or treatment failure when compared with conventional therapy plus benazepril in dogs with congestive heart failure (CHF) attributable to MMVD. ANIMALS: Two hundred and sixty client-owned dogs in CHF caused by MMVD were recruited from 28 centers in Europe, Canada, and Australia. METHODS: A prospective single-blinded study with dogs randomized to PO receive pimobendan (0.4-0.6 mg/kg/d) or benazepril hydrochloride (0.25-1.0 mg/kg/d). The primary endpoint was a composite of cardiac death, euthanized for heart failure, or treatment failure. RESULTS: Eight dogs were excluded from analysis. One hundred and twenty-four dogs were randomized to pimobendan and 128 to benazepril. One hundred and ninety dogs reached the primary endpoint; the median time was 188 days (267 days for pimobendan, 140 days for benazepril hazard ratio = 0.688, 95% confidence limits [CL]=0.516-0.916, P= .0099). The benefit of pimobendan persisted after adjusting for all baseline variables. A longer time to reach the endpoint was also associated with being a Cavalier King Charles Spaniel, requiring a lower furosemide dose, and having a higher creatinine concentration. Increases in several indicators of cardiac enlargement (left atrial to aortic root ratio, vertebral heart scale, and percentage increase in left ventricular internal diameter in systole) were associated with a shorter time to endpoint, as was a worse tolerance for exercise. CONCLUSIONS AND CLINICAL IMPORTANCE: Pimobendan plus conventional therapy prolongs time to sudden death, euthanasia for cardiac reasons, or treatment failure in dogs with CHF caused by MMVD compared with benazepril plus conventional therapy.