Heart rate and arrhythmia frequency of normal cats compared to cats with asymptomatic hypertrophic cardiomyopathy

ObjectivesTo compare heart rate and arrhythmia frequency and complexity in a normal population of cats to a population of cats with hypertrophic cardiomyopathy (HCM).Animals17 cats with HCM and 15 cats with normal echocardiograms.MethodsResults for echocardiography, electrocardiography, Doppler blood pressure, and 24-h Holter monitoring were compared between groups.ResultsThere was no difference in heart rate between HCM cats and normal cats regardless of modality used. All (17/17) HCM cats had ventricular arrhythmias (geometric mean 124 complexes/24 h) with 82% (14/17) exhibiting complex arrhythmias (couplets, triplets, or ventricular tachycardia). Most (14/15) normal cats had ventricular arrhythmias (geometric mean 4 complexes/24 h), but only 20% (3/15) exhibited complexity. HCM cats had significantly more total ventricular complexes, ventricular premature complexes and accelerated idioventricular rhythm than normal cats (P < 0.0001, P < 0.0001, and P = 0.01, respectively). Eighty eight percent (15/17) of HCM cats had supraventricular arrhythmias (geometric mean 9 complexes/24 h) with 23% (4/17) exhibiting complexity. Sixty percent (9/15) of normal cats had supraventricular arrhythmias (geometric mean 1 complex/24 h) with 13% (2/15) exhibiting complexity. Cats with hypertrophic cardiomyopathy had significantly more supraventricular complexes than normal cats (P = 0.0148).ConclusionCats with asymptomatic HCM have more frequent and complex ventricular and supraventricular arrhythmias than normal cats but do not have different overall heart rates compared to normal cats. Further studies are needed to determine if these arrhythmias are associated with an increased risk of sudden cardiac death or influence long-term survival.     

Primary pulmonic infundibular stenosis in 12 cats: Natural history and the effects of balloon valvuloplasty

ObjectivesTo evaluate the natural history of primary pulmonic infundibular stenosis in cats and the effects of balloon valvuloplasty.BackgroundPrimary pulmonic infundibular stenosis is an uncommon congenital defect in cats. The natural history of the disease has not been described. Information regarding balloon valvuloplasty in the cat is limited.AnimalsRecords between January 1, 1999 and December 31, 2005 were reviewed and cats with a confirmed echocardiographic diagnosis of primary pulmonic infundibular stenosis, a complete medical history, and no evidence of significant systemic disease were identified.MethodsEchocardiographic, electrocardiographic, and radiographic findings are described. The natural history of those with severe disease was compared to those with mild to moderate disease. Balloon valvuloplasty was performed in six of the cats. The technique used is described.ResultsA stenotic gradient ≥70 mmHg and a right ventricular outflow tract (measured at the level of the stenosis) to pulmonary valve annulus ratio of ≤0.25 were consistent with clinical and echocardiographic severe disease. Cats with severe disease had a very guarded prognosis with a high incidence of congestive heart failure (CHF). Balloon valvuloplasty was successfully performed in 4 of the cats and appeared to improve prognosis, especially if performed prior to the development of CHF. Concurrent hypertrophic cardiomyopathy complicated the outcome in some cats.ConclusionsSevere primary pulmonic infundibular stenosis carries a very guarded prognosis in the cat. Balloon valvuloplasty should be considered in the presence of severe disease and should be performed prior to the development of CHF if possible. The presence of concurrent hypertrophic cardiomyopathy may complicate the prognosis.     

Dilated cardiomyopathy in cats: survey of veterinary cardiologists and retrospective evaluation of a possible association with diet

Introduction/objectivesThe objectives were to conduct a survey of cardiologists on their recent experiences with cats that have dilated cardiomyopathy (DCM) and to retrospectively review individual cases of feline DCM.Animals, materials and methodsPart one: A survey was distributed to cardiologists with questions regarding caseload and clinical management of cats with DCM diagnosed over the past two years. Part two: Cardiologists completing the survey were invited to submit data from cats recently diagnosed with DCM. Data on signalment, clinical signs, diet, echocardiographic measurements and outcome were recorded.ResultsPart one: From 52 completed surveys, many cardiologists responded that measuring and supplementing taurine and recommending a diet change in cats with DCM are common practices. Few (15%) cardiologists reported an increase in the number of feline DCM cases over the past two years, although some had cases that improved even if taurine deficiency was not present. Part two: Twenty of 37 (54%) cats ate low pea/lentil (low PL) diets, and 14/37 (38%) ate high PL diets at the time of diagnosis; three had incomplete diet information. Two of 13 cats (15%) in which taurine was measured had levels below the reference range. After adjusting for other variables, cats eating high PL diets that changed diets after diagnosis had a significantly longer survival time than that of cats eating high PL diets that did not change diets after diagnosis (P = 0.025).ConclusionsAdditional research is warranted to determine whether there could be a possible association between diet and DCM in cats.     

Congenital supravalvular mitral stenosis in 14 cats

ObjectivesTo describe the clinical features of congenital supravalvular mitral stenosis (SVMS) in cats.BackgroundSupravalvular mitral stenosis is an uncommon congenital cardiac defect that has not been previously reported in a series of cats.Animals14 cats with SVMS.MethodsMedical records, relevant diagnostic studies and preserved pathology specimens were reviewed.ResultsCats were presented over a wide age range (5 months–10 years; median 3 years); males (n = 9) and the Siamese breed were over-represented. Presenting complaints included respiratory distress (n = 6), hindlimb paralysis due to aortic thromboembolism (n = 5) and asymptomatic heart murmur (n = 3). Echocardiographic examination often identified pulmonary hypertension (PHT) (n = 7) and concurrent cardiac abnormalities (n = 7), especially partial atrioventricular septal defect (PAVSD) (n = 4). Status 12 months following diagnosis was known for 9 cats; 8 of these had died or were euthanized.ConclusionsCats with SVMS are usually presented as young adults for respiratory signs attributable to congestive heart failure, aortic thromboembolism or incidental murmur identification. Congestive heart failure, PHT and concurrent congenital cardiac abnormalities (specifically PAVSD) are common. Long-term prognosis for symptomatic cats is poor.     

Acute Pancreatitis in Cats With Hepatic Lipidosis

The purpose of this study was to characterize the incidence, clinical features, and prognosis of acute pancreatitis in cats with hepatic lipidosis. Of 13 cats histologically diagnosed with hepatic lipidosis between July 1988, and November 1989,5 (38%) were also histologically diagnosed with acute pancreatitis. In cats with hepatic lipidosis alone, the signalment, history, physical examination, and clinicopatho-logic findings were generally indistinguishable from those of cats with concurrent acute pancreatitis except that cats with acute pancreatitis were more likely to be cachectic and to have coagulation abnormalities. Hepatomegaly was seen on abdominal radiographs in both groups. Of the 5 cats with concurrent acute pancreatitis, abdominal ultrasonography detected 1 cat with a hypoechoic pancreas and 5 with peritoneal effusion; those abnormalities were not seen in cats without concurrent acute pancreatitis. Cats with concurrent acute pancreatitis had only a 20% recovery rate, compared with a 50% recovery rate in cats with hepatic lipidosis alone. We conclude that cats with hepatic lipidosis should be rigorously evaluated for concurrent acute pancreatitis because of 1) the rate of disease coincidence, 2) the inability of signalment, history, physical examination, and clinicopathologic findings to adequately distinguish between hepatic lipidosis and acute pancreatitis, 3) the worse prognosis associated with concurrent acute pancreatitis, and 4) the opposing nutritional strategies for hepatic lipidosis and acute pancreatitis. (Journal of Veterinary Internal Medicine 1993; 7:205–209. Copyright © 1993 by the American College of Veterinary Internal Medicine.)     

Twenty-four hour Holter monitoring of unsedated healthy cats in the home environment

Objective

To determine the heart rate, rhythm, number of ventricular premature complexes (VPCs) and atrial premature complexes (APCs) in unsedated cats using Holter monitoring.

Animals, materials and methods

Twenty-three healthy client owned cats were used. Clinical examination, blood pressure measurements, echocardiographic examination and serum biochemical analysis were performed. A lightweight Holter was used in the home environment.

Results

Three-lead electrocardiographic registrations of good quality were obtained from all cats. Normal sinus rhythm was present in all cats. The median heart rate was 165 beats per minute (bpm), range 70-303 bpm. Mean heart rate varied significantly with age and gender. Sinus arrhythmia occurred intermittently in 18 cats (78%). Uncommon ventricular premature complexes occurred in 18 (78%) of the cats. The median number of VPCs per cat was 3 complexes/24 h period, range 0-146. Cats 7-15 years of age had significantly more VPCs than cats 1-6 years of age (median 6 versus 1 per 24 h period, p = 0.04). A single APC occurred in one cat (4%).

Conclusions

Cats commonly have intermittent sinus arrhythmia. Many healthy cats have rare single VPCs per 24 h period. Old cats have significantly more VPCs than young cats. The heart rate varies significantly with age and gender.     

Multi-centered investigation of a point-of-care NT-proBNP ELISA assay to detect moderate to severe occult (pre-clinical) feline heart disease in cats referred for cardiac evaluation

ObjectiveTo prospectively evaluate the diagnostic accuracy of a point-of-care (POC) N-terminal pro-B-type natriuretic peptide (NT-proBNP) ELISA to assess the likelihood of moderate to severe occult heart disease (OcHD) in a clinical population of cats suspected to have heart disease.AnimalsOne hundred and forty-six asymptomatic client-owned cats with a heart murmur, gallop rhythm, arrhythmia, or cardiomegaly.MethodsPhysical examination, blood pressure measurement and echocardiography were performed prospectively. Point-of-care ELISA was visually assessed as either positive or negative by a reader blinded to the echocardiographic results.ResultsForty-three healthy cats, 50 mild OcHD, 31 moderate OcHD, 6 severe OcHD, and 16 cats equivocal for OcHD were examined. Cats with OcHD included 65 with hypertrophic cardiomyopathy, 6 with restrictive or unclassified cardiomyopathy, 1 with arrhythmogenic right ventricular cardiomyopathy, and 15 with non-cardiomyopathic forms of heart disease. Point-of-care ELISA differentiated cats with moderate or severe OcHD with sensitivity/specificity of 83.8%/82.6% and overall accuracy of 82.9%. Positive POC ELISA increased likelihood of moderate or severe OcHD by a factor of 4.8 vs. those that tested negative. Point-of-care ELISA differentiated cats with moderate or severe cardiomyopathic OcHD with sensitivity/specificity of 88.6%/81.3% and overall accuracy of 83.2%.ConclusionIn a select sample of cats referred for cardiac evaluation, positive POC NT-proBNP ELISA increases likelihood of moderate to severe OcHD while negative POC NT-proBNP ELISA result excludes moderate to severe OcHD.     

Risk factors,prognostic indicators,and outcome of pyothorax in cats: 80 cases (1986-1999)

OBJECTIVE: To identify risk factors associated with development of pyothorax in cats, assess survival rates for cats that are treated, determine prognostic indicators, and determine recurrence rates. DESIGN: Retrospective study. ANIMALS: 80 cats with pyothorax and 212 control cats. PROCEDURE: History; month of evaluation; physical examination findings; results of hematologic, serum biochemical, and retrovirus testing; radiographic findings; outcome; recurrence rate; and necropsy findings were recorded. For control cats, age, sex, breed, indoor versus outdoor status, vaccination history, and single- versus multi-cat household status were recorded. RESULTS: Cats from multi-cat households were 3.8 times as likely (95% confidence interval, 1.9 to 8.2) to develop pyothorax, compared with cats from single-cat households. Indoor or outdoor status was not a risk factor. Cats with pyothorax were significantly younger (mean, 3.83 +/- 3.43 years) than controls (mean, 5.62 +/- 5.27 years). Nonsurvivors had significantly lower heart rates than survivors. Hypersalivation was significantly more common in nonsurvivors (11/39; 26.8%) than survivors (1/39; 3%). Overall, 48.8% (39/80) of cats survived. When cats that were euthanatized without treatment were excluded from analyses, the survival rate was 66.1% (39/59). Pyothorax recurred in 1 of 17 cats for which follow-up information was obtained. CONCLUSIONS AND CLINICAL RELEVANCE: Cats with pyothorax that received treatment had a fair to good prognosis, with low recurrence rates in survivors. Hypersalivation and low heart rate were associated with worse clinical outcome. Cats with pyothorax were likely to come from multi-cat households.     

Indications for and outcome of positive-pressure ventilation in cats: 53 cases (1993-2002)

OBJECTIVE: To determine indications for and outcomes of positive-pressure ventilation (PPV) in cats, document ventilator management, and identify factors associated with outcome. DESIGN: Retrospective study. ANIMALS: 53 cats that underwent PPV. PROCEDURE: Information on signalment, history, concurrent diseases, clinical findings, results of venous blood gas analyses and clinicopathologic testing, treatment, ventilator settings, and outcome was retrieved from the medical records. Data for cats that survived were compared with data for cats that died or were euthanatized while undergoing PPV RESULTS: PPV was initiated for management of respiratory failure (36 cats [68%]), cardiac arrest (9 [17%]), neurologic impairment (6 [11%]), and nonresponsive hypotension (2 [4%]). Eight cats (15%) survived, 19 (36%) died, and 26 (49%) were euthanatized while undergoing PPV. Cats that survived had a longer duration of ventilation than did those that died or were euthanatized and had a significantly higher incidence of ventilator-associated pneumonia. Signalment and ventilator settings were not associated with outcome. Cats that had no clinical evidence of pulmonary disease but required PPV because of primary neurologic disease had a higher survival rate (2/6) than did cats that required PPV because of respiratory failure (5/36), cardiac arrest (1/9), or nonresponsive hypotension (0/2). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the survival rate for cats requiring PPV may be lower than reported survival rates for dogs. Death was attributable to progressive respiratory failure, non-responsive hypotension, kidney failure, or neurologic impairment.     

Supraventricular tachycardia in dogs: 65 cases (1990–2007)

Objective – To characterize the signalment, clinical findings, and prognosis of dogs with supraventricular tachycardia (SVT). Design – Retrospective study. Setting – North Carolina State University Veterinary Teaching Hospital. Animals, Intervention, and Measurements – Case selection included all patients at the veterinary teaching hospital with SVT during years 1990–2007. Medical records from dogs with at least 1 recorded episode of SVT were extracted. The signalment, history, electrocardiographic, radiographic, and echocardiographic findings, therapy, and response to therapy were reviewed and summarized. Follow‐up was conducted to determine the date and cause of death. Kaplan‐Meier survival curves were constructed and analyzed. The relationships between patient characteristics and responses to therapy and prognosis were evaluated. Main Results – Sixty‐five records documented a diagnosis of SVT. Sixty‐two percent were males. Labrador Retrievers and Boxers were overrepresented compared with the general hospital population. Median age at presentation was 9 years (range 0.5–15.5 y). The median heart rate during SVT was 270/minute (range 187–375/min). The most common presenting complaint was syncope (30%), 23% were asymptomatic at the time of diagnosis. Most dogs had structural heart disease (65%). Median survival was 472 days (<1–2007 d). Identification of sustained SVT (>30 s) did not affect survival (P=0.50), nor did the presence of congestive heart failure (P=0.70). Conclusions – The majority of dogs with SVT had structural heart disease or a severe concurrent illness at the time of SVT diagnosis. SVT, though often a persistent and occasionally sustained arrhythmia, does not appear to be a primary factor in mortality.     

Effect of treatment with atenolol on 5-year survival in cats with preclinical (asymptomatic) hypertrophic cardiomyopathy

ObjectivesTo investigate the effect of treatment with atenolol on 5-year survival in cats with preclinical hypertrophic cardiomyopathy (HCM).Animals63 Client-owned cats with preclinical HCM and 31 healthy control cats.MethodsProspective, observational, open-label, clinical cohort study. Cats with HCM were diagnosed by echocardiography, treated with atenolol (6.25–12.5 mg q12h, PO; n = 42) or untreated (n = 21), and were observed for 5 years after enrollment. The study end point was death from any cause. Cats of similar body weight, age, gender, and breed without evidence of heart disease were studied concurrently and served as controls.ResultsDuring the observational period, 27 cats with HCM died; 14 (22%) due to cardiac disease and 13 (21%) due to non-cardiac disease. Ten control cats (32%) died of non-cardiac disease. There was no significant difference (P = 0.307) in all-cause mortality between control and HCM. Cardiac mortality was higher in cats with HCM compared to control cats (P = 0.005). There was no significant difference in all-cause mortality (P = 0.729) and cardiac mortality (P = 0.897) between cats with HCM treated or untreated with atenolol. Age and left atrial size at diagnosis were the only predictors of 5-year outcome.ConclusionsOur study failed to demonstrate an effect of atenolol on 5-year survival in cats with preclinical HCM.     

Double-outlet right atrium in a 9 year-old cat

Double-outlet right atrium (DORA) is a type of atrioventricular septal defect that is described as an extreme leftward deviation of the lower portion of the interatrial septum, resulting in insertion into the atrial wall left and posterior to the mitral orifice. This rare anomaly, which has been reported in humans and only just recently in cats, was identified by transthoracic echocardiography in a 9 year-old cat that was presented for further evaluation of a tachyarrhythmia and cardiomegaly. This case report describes the diagnostic findings in this cat and summarizes the anatomy, classification and clinical consequences of this rare congenital heart defect.     

Prospective echocardiographic and tissue Doppler screening of a large Sphynx cat population: Reference ranges,heart disease prevalence and genetic aspects

Objectives(1) To investigate heart morphology and function using echocardiography and tissue Doppler imaging (TDI), (2) to determine heart disease prevalence and characteristics, and (3) to assess potential genetic features in a population of Sphynx cats presented for cardiovascular screening.AnimalsA total of 147 echocardiographic examinations, including 33 follow-ups, were performed by trained observers on 114 Sphynx cats of different ages (2.62 ± 1.93 years [0.5–10.0]) from 2004 to 2011.MethodsSphynx cats underwent a physical examination, conventional echocardiography, and, if possible, two-dimensional color TDI.ResultsConventional echocardiographic findings included 75/114 normal (65.8%) and 39/114 (34.2%) abnormal examinations with a diagnosis of either congenital heart diseases (n = 16) or hypertrophic cardiomyopathy (HCM, n = 23). In adult healthy cats, a significant body weight effect was observed for several echocardiographic variables, including end-diastolic left ventricular (LV) free wall (P < 0.01), interventricular septum (P < 0.001), and LV diameter (P < 0.001). Mitral valve dysplasia (MVD) was observed as a single or associated defect in 15/16 cats with congenital heart diseases. A significant increase in HCM prevalence (P < 0.001) was observed according to age. The pedigree analysis of a large family (n = 81) suggested an autosomal dominant mode of inheritance with incomplete penetrance for HCM.ConclusionsBody weight should be taken into account when interpreting values of diastolic myocardial wall thicknesses in Sphynx cats. Additionally, HCM and MVD are two relatively common heart diseases in this feline breed. More pedigree data are required to confirm the inheritance pattern of HCM at the breed level.     

Disseminated intravascular coagulation in cats

The purpose of this study was to describe the clinical characteristics of cats with disseminated intravascular coagulation (DIC), including associated diseases and hemostatic abnormalities, and to identify risk factors for death and treatments that potentially altered outcome. Medical records for cats with DIC from 1990-2004 were evaluated retrospectively. Inclusion criteria were the presence of an underlying disorder associated with DIC and either postmortem examination findings of intravascular fibrin deposition or thrombosis, or both of 2 or more organs or coagulation profiles that meet 3 of 5 criteria: prolonged prothrombin time (PT), activated partial thromboplastin time (aPTT), presence of fibrin degradation products (FDP), low plasma fibrinogen (FIB) concentration, and thrombocytopenia (<160,000 platelets/microL). Signalment, historical data, clinical findings, clinicopathologic data, underlying disorders, management, and outcome were recorded. Forty-six cats fulfilled the criteria for DIC. Cats ranged in age from 7 weeks to 17 years (median, 9 years). Hemorrhage was noted in 7 of 46 cats (15%). Three of 46 cats (7%) survived, whereas 43 of 46 (93%) died or were euthanized. The most common underlying disorders were lymphoma, other forms of neoplasia, pancreatitis, and sepsis. There was no association detected between outcome and signalment; underlying disease; hemorrhage; abnormalities in aPTT, FIB, FDPs, platelet count; transfusion of blood products; and heparin therapy. However, the median PT of nonsurvivors was more prolonged than in survivors (P < .005). DIC in cats can result from a variety of neoplastic, infectious, and inflammatory disorders, and is associated with a high case fatality rate.     

Anemia in cats with hemotropic mycoplasma infection: Retrospective evaluation of 23 cases (1996–2005)

This study summarizes the diagnostic findings from all anemic cats diagnosed with hemotropic mycoplasma (HM) infections at the Western College of Veterinary Medicine — Veterinary Teaching Hospital between 1996 and 2005. The objectives were to determine the frequency of HM-induced anemia among all cats presented with anemia during this period, the clinical findings and risk factors associated with clinical HM infection, and factors affecting or predicting survival. Medical records were examined from 23 cats with HM-induced anemia from the total of 170 cats diagnosed with anemia during this period. The frequency of HM-induced anemia was 14% (23/170) among all anemic cats. Cats with HM-induced anemia were less likely to be purebred (P = 0.04) than other cats with anemia. Of the cats with HM-induced anemia, those with positive retroviral status (P = 0.01), concurrent illness (P < 0.01), or lack of erythroid regeneration (P = 0.01) were most likely to die. The 1-year survival of HM-infected cats was 65% (13/20).     

Utility of measuring plasma N-terminal pro-brain natriuretic peptide in detecting hypertrophic cardiomyopathy and differentiating grades of severity in cats

Background: Cats with hypertrophic cardiomyopathy (HCM) often have no clinical signs or subtle signs. Measurement of N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) has been demonstrated in people to be highly specific for heart disease and also correlates with severity of HCM. NT‐proBNP may also be valuable in detecting and grading HCM in cats, but results to date have been equivocal. Objectives: The aims of this study were to evaluate NT‐proBNP as a screening test for diagnosis of HCM in cats and determine an appropriate cut‐off value and to determine if NT‐proBNP concentrations correlated with severity of HCM in cats. Methods: Plasma NT‐proBNP concentrations were measured in 201 cats using an ELISA designed for use in cats. Cats were classified using echocardiography as clinically healthy controls (n=99) or cats with equivocal (n=9), mild (n=15), moderate (n=17), or severe (n=61) HCM. Results: NT‐proBNP concentrations (median; 25th–75th interquartile percentiles) in mildly (216.1; 87.6–392.5 pmol/L), moderately (282.7; 131.9–466.6 pmol/L), and severely (839.5; 655.3–1046.4 pmol/L) affected cats were significantly higher than those in healthy controls (18.9; 3.4–62.4 pmol/L). Concentrations in severely affected cats were significantly higher than in cats from other HCM groups. There was no significant difference between mild and moderate HCM. Cut‐off values >49 pmol/L had a sensitivity of 97.8% and specificity of 66.7%; >100 pmol/L had a sensitivity of 92.4% and specificity of 93.9%; and >150 pmol/L had a sensitivity of 88% and a specificity of 100%. Conclusions: NT‐proBNP with a cut‐off value of >100 pmol/L was useful in detecting even mild HCM. Cats with increased NT‐proBNP concentrations should be examined by echocardiography.     

Clinical and echocardiographic findings of pulmonary artery stenosis in seven cats

ObjectivesDescribe the clinical, electrocardiographic (ECG), radiographic and echocardiographic findings in cats with isolated pulmonary artery stenosis. Assess the usefulness of systolic and diastolic Doppler measurements at predicting stenosis severity.BackgroundPulmonary artery stenosis is an infrequent congenital cardiac defect in humans that has not been reported in cats. In humans, pulmonary artery stenosis is usually seen in conjunction with other cardiac defects and may lead to clinical signs if severe.Animals, materials and methodsSeven cats with pulmonary artery stenosis were retrospectively evaluated. Medical records, radiographs, ECGs, echocardiograms and angiocardiograms were reviewed. Severity of stenosis was assessed by two-dimensional and color Doppler echocardiographic evaluation and clinical findings. Peak systolic and diastolic gradients across the stenosis, and systolic and diastolic pressure decay half-times were graded using echocardiography. In addition, the duration of antegrade flow during diastole was subjectively assessed. Univariate analyses were performed to assess the best variable to predict stenosis severity.ResultsConcurrent congenital defects were not identified. Only cats with severe obstruction showed clinical signs including exertional dyspnea and lethargy. Diastolic Doppler measurements were superior to systolic measurements at predicting severity of stenosis. Antegrade flow throughout diastole and/or a diastolic pressure half-time of >100 ms indicated severe obstruction. The prognosis for pulmonary artery stenosis appears to be good regardless of severity.ConclusionAmong cats with pulmonary artery stenosis, clinical signs are uncommon and prognosis is good. Doppler assessment of diastolic flow appears to be superior to systolic flow at predicting severity.     

Effects of treatment with ivabradine and atenolol on reproducibility of echocardiographic indices of left heart size and function in healthy cats

ObjectivesData on reproducibility of echocardiographic indices in cats are commonly derived from studies in healthy, non-treated animals. However, medical treatment may alter reproducibility of such data possibly influencing interpretation of results of clinical trials assessing the effects of drugs on cardiovascular function. The objectives were therefore to investigate the effects of ivabradine and atenolol on reproducibility of echocardiographic indices of left heart function.AnimalsEight healthy cats.MethodsRepeated echocardiographic examinations were performed by two observers in mildly sedated cats at baseline and after four weeks of treatment (Group 1, ivabradine 0.3 mg/kg q12 h PO, n = 4; Group 2, atenolol 6.25 mg/cat q12 h PO, n = 4) in a prospective, double-blind, randomized study. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and between-day intraobserver variability of all echocardiographic indices. Variability was expressed as coefficient of variation (CV) and the absolute value below which the difference between two measurements lay with 95% probability. Effects of treatments on variability were compared using linear mixed effects models ANOVA and Fisher's exact test.ResultsOverall, CVs ranged from 0.5 to 50.6% at baseline, 0.5–45.5% after ivabradine, and 0.5–23.3% after atenolol. Reproducibility of all variables determined did neither improve nor worsen consistently after either treatment although atenolol exhibited a tendency toward higher reliability with none of the CVs exceeding 24% as compared to ivabradine.ConclusionsTreatment of healthy cats with either atenolol or ivabradine had only minor effects on reproducibility of echocardiographic data. Whether these findings can be extrapolated to cats with hypertrophic cardiomyopathy deserves further study.     

Use of pimobendan in 170 cats (2006–2010)

Hypothesis/ObjectivesTo describe the therapeutic use of pimobendan in cats, describe the patient population to which it was administered, document potential side effects and report the clinical course following administration of pimobendan in conjunction with standard heart failure therapy. It is hypothesized that cats with advanced heart disease including congestive heart failure from a variety of causes will tolerate pimobendan with a minimum of side effects when used in treatment in conjunction with a variety of other medications.Animals, materials and methodsOne hundred and seventy client owned cats with naturally occurring heart disease, one hundred and sixty four of which had congestive heart failure. Medical records were reviewed and owners and referring veterinarians were contacted for follow-up data. Data collected included pimobendan dose, other medications administered concurrently, data collected at physical examination, presence or absence of heart failure, adverse effects, classification of heart disease, echocardiographic data and survival time. The data were analyzed for significance between the initial visit and any follow-up visits.ResultsAll cats were treated with pimobendan. The median pimobendan dose was 0.24 mg/kg q 12 h. Pimobendan was used in combination with multiple concurrent medications including angiotensin converting enzyme inhibitors, diuretics and anti-thrombotics. Five cats (3.0%) had potential side effects associated with pimobendan. One cat (0.6%) had presumed side effects severe enough to discontinue pimobendan use. Median survival time for 164 cats with congestive heart failure after initiation of pimobendan was 151 days (range 1–870).ConclusionPimobendan appears to be well tolerated in cats with advanced heart disease when used with a variety of concurrent medications. Randomized controlled studies need to be performed to accurately assess whether it is efficacious for treatment of congestive heart failure in cats.