Hypertrophic Cardiomyopathy In Cats Research Articles

Acute heart failure and cardiogenic arterial thromboembolism in cats: clinical and echocardiographic features

Acute heart failure and arterial thromboembolism are common complications of hypertrophic cardiomyopathy in cats. These conditions have many common links in pathogenesis, so analyzing the differences between them improves the understanding of the impact of vessel occlusion on the body. In the study, 40 clinical cases were analyzed and two groups were formed: the first – cats with arterial thromboembolism and the second – cats with acute heart failure. The data from anamnesis, clinical examination and echocardiographic examination were collected. Age, sex, breed, weight, temperature, frequency of respiratory movements, signs of dyspnea, presence of pulmonary edema, presence of free fluid in the chest and pericardial cavities were analyzed. The following echocardiographic parameters were analyzed: left ventricular wall thickness, left ventricular end-systolic and end-diastolic dimensions, diameters of the aorta and left atrium, heart rate and left ventricular contraction fraction. It was established that the majority of animals from both groups were males. Acute heart failure was registered mainly in young cats (M = 3.7), in contrast to animals with arterial thromboembolism (M = 6.7), (P < 0.01). There was no significant difference in the values of rectal temperature, weight, heart rate, aortic diameter, and left ventricular contraction fraction. Most animals from both groups had signs of dyspnoea. The difference in the frequency of respiratory movements was significant (P < 0.01). In cats with acute heart failure, pulmonary edema was diagnosed in 85%, free fluid in the thoracic and/or pericardial cavities in 55 %. In animals with thromboembolism, edema was found in 45 %, and effusion in the chest and/or pericardial cavities in 30 % of animals. The established differences indicate that arterial thromboembolism develops in animals that have had heart pathology for a longer period of time, whereas acute heart failure occurs more suddenly in cats.

Radiographic findings of cardiopulmonary structures can predict hypertrophic cardiomyopathy and congestive heart failure in cats.

This study aimed to find the radiographic characteristics for the detection of hypertrophic cardiomyopathy (HCM) and congestive heart failure (CHF) in cats. Healthy cats (n = 35) and HCM cats with (21) and without (22) CHF. On radiography, the cardiac size using vertebral heart score, left atrium enlargement (LAE), and dilation of the pulmonary vessels were assessed. The sensitivity and specificity of the radiographic characteristics regarding LAE were evaluated with the echocardiographic left atrium to aortic root ratio as a reference. In HCM cats, cardiomegaly, LAE, and dilation of the caudal pulmonary artery were found compared with those in healthy cats. The LAE could be predicted using the elevation of the carina with 94.12% specificity but 17.5% sensitivity. When CHF developed, LAE and dilation of the caudal pulmonary vein (PV) were significantly different compared with those in HCM cats without CHF. The distal side of the summated shadow made by the right caudal PV with the ninth rib in HCM cats with CHF was significantly larger than that in HCM cats without CHF and a cut-off value of 5.35 mm was drawn with 75% sensitivity and 100% specificity. Although there was an overlapping of radiographic findings between healthy and HCM cats, radiographic assessment of LAE can be useful for predicting HCM and the distal side of the summated shadow made by the right caudal PV with the ninth rib can predict CHF in HCM cats.

Systolic third sound associated with systolic anterior motion of the mitral valve in cats with obstructive hypertrophic cardiomyopathy.

Third heart sounds in cats frequently are associated with hypertrophic cardiomyopathy (HCM) but their exact characterization and timing within the cardiac cycle remains unknown. Characterize third heart sounds in cats by phonocardiography and test the ability of 3 observers with different levels of experience and training to recognize third systolic heart sounds in cats. Fifty client-owned cats of different breeds presented for heart screening. Cats were prospectively assessed using an electronic stethoscope (with digital recording) and then underwent full conventional echocardiographic examination. Audio recordings were blindly assessed in a random order by 3 observers: the cardiologist who collected clinical data, as well as a trained and an untrained junior veterinarian. Cohen's kappa coefficients were calculated to quantify agreement between the opinion of each observer and the echocardiography results (considered the gold standard). Twenty cats had a third systolic sound on phonocardiography and an obstructive HCM phenotype with systolic anterior motion of the mitral valve (SAM) on echocardiography. Agreement with echocardiography was very good for the experienced cardiologist, substantial for the trained junior veterinarian, and poor for the untrained junior veterinarian (kappa of 0.92, 0,64, and 0.08, respectively). We describe here a new auscultatory abnormality in cats with obstructive HCM. It could help a trained non-cardiologist veterinarian in suspecting obstructive HCM in cats based on auscultation only.

Exploration of Mediators Associated with Myocardial Remodelling in Feline Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) affects both humans and cats and exhibits considerable interspecies similarities that are exemplified by underlying pathological processes and clinical presentation to the extent that developments in the human field may have direct relevance to the feline disease. Characteristic changes on histological examination include cardiomyocyte hypertrophy and interstitial and replacement fibrosis. Clinically, HCM is characterised by significant diastolic dysfunction due to a reduction in ventricular compliance and relaxation associated with extracellular matrix (ECM) remodelling and the development of ventricular hypertrophy. Studies in rodent models and human HCM patients have identified key protein mediators implicated in these pathological changes, including lumican, lysyl oxidase and TGF-β isoforms. We therefore sought to quantify and describe the cellular location of these mediators in the left ventricular myocardium of cats with HCM and investigate their relationship with the quantity and structural composition of the ECM. We identified increased myocardial content of lumican, LOX and TGF-β2 mainly attributed to their increased expression within cardiomyocytes in HCM cats compared to control cats. Furthermore, we found strong correlations between the expressions of these mediators that is compatible with their role as important components of cellular pathways promoting remodelling of the left ventricular myocardium. Fibrosis and hypertrophy are important pathological changes in feline HCM, and a greater understanding of the mechanisms driving this pathology may facilitate the identification of potential therapies.

РЕЗУЛЬТАТЫ ЭЛЕКТРОКАРДИОГРАФИЧЕСКОГО ИССЛЕДОВАНИЯ ПРИ ГКМП У РАЗНОВОЗРАСТНЫХ КОШЕК

Cardiomyopathies are a heterogeneous group of myocardial diseases with varying phenotypes and prognosis. Feline cardiomyopathies are common, and cardiovascular disease is among the 10 most common causes of death in cats. Hypertrophic cardiomyopathy (HCM) is a common cause of heart failure, arterial thromboembolism, and sudden death in cats. HCM is a primary myocardial lesion characterized by unexplained left ventricular hypertrophy (LVH) and impaired myocardial relaxation. The cause of primary or idiopathic in cats is unknown, but hereditary pathology probably exists in many cases. The disease is widespread in breeds such as Maine Coon, Persian, Ragdoll, American Shorthair. There are also reports of HCM in littermates and other close relatives of domestic shorthair cats. The method of electrocardiography is quite sensitive in the diagnosis of cardiomyopathies in humans, therefore, the study of ECG signs of HCM in cats, as well as the study of the dynamics of disease progression, the development and improvement of the treatment of this disease is an urgent scientific and practical problem in veterinary medicine, which has not been sufficiently resolved to date. According to the obtained ECG data, it can be concluded that recording in animals of different ages, as well as in animals that have a hereditary predisposition to the development of this disease, can play a key role in diagnosing an early stage of cardiomyopathy. The prevalence of HCM in cats with a predisposition to this disease is much higher than in cats without this genetic predisposition. Further studies involving more cats with HCM, secondary left ventricular hypertrophy, and normal hearts are proposed to better understand the heterogeneity and complexity of this myocardial disease.

Tpeak-Tend, a novel electrocardiographic marker in cats with hypertrophic cardiomyopathy-a brief communication.

Hypertrophic cardiomyopathy (HCM) is the most common heart disease in feline species. ECG allows assessing parameters that can help in the diagnosis and risk stratification of conditions that occur secondary to this disease. This study aimed to evaluate electrocardiographic markers Tpte and Tpte/QT in leads I, II, III, aVR, aVL and aVF in control and HCM cats. Data were obtained from 63 domestic cats allocated in a Control (n = 40) and an HCM (n = 23) group. Tpte and Tpte/QT of all individuals were measured in all limb leads (I, II, III, aVR, aVL, aVF). We constructed ROC curves to evaluate the sensitivity and specificity of markers to identify HCM-affected cats. Logistic regression analysis was performed to assess the risks of cats having HCM based on Tpte indexes. Tpte in leads II (p < 0.01), aVR (p < 0.01), aVL (p < 0.01), and aVF (p < 0.01) had significantly higher results in the HCM group. Tpte/QT showed no statistical difference between groups in any of the derivations evaluated. A Tpte > 27.5ms in lead aVF showed an accuracy of 83.3% to identify individuals with HCM in our study. Univariable logistic regression reveals that cats with Tpte in aVR and aVF > 27.5ms and in aVL > 26.5ms had 1.28, 12 and 1.16 respectively, more chances of having HCM. The prolongation of Tpte may be a noninvasive electrocardiographic complementary tool to help differentiate patients with and without hypertrophic cardiomyopathy.

Natural history of hypertrophic cardiomyopathy in cats from rehoming centers: The CatScan II study.

The natural history of hypertrophic cardiomyopathy (HCM) in cats has been mainly studied in cats referred for suspected heart disease, which can skew the results towards cats with clinical signs. Few data are available on factors associated with development of HCM in cats. (1) Clinical variables can predict which cats will develop HCM; (2) HCM in cats not referred for suspected heart disease is associated with a low rate of cardiovascular events. One hundred seven cats from rehoming centers without a history of clinical signs of cardiac or systemic disease at the time of adoption. Prospective longitudinal study. After rehoming, shelter cats were reexamined for serial echocardiograms. Cox regression analysis was used to identify predictors of development of HCM in cats that were normal at baseline. Adverse cardiovascular events including heart failure, thromboembolism, or sudden death were recorded. Cats were monitored for a median of 5.6 [1.2-9.2] years. At baseline, 68/107 cats were normal, 18/107 were equivocal and 21/107 had HCM. Nineteen cats developed HCM during the study period. The factors at baseline associated with increased hazard of developing HCM were lower left atrial fractional shortening, higher left ventricular fractional shortening, and higher body weight. Cardiovascular events were observed in 21% of cats with HCM. Cardiovascular events were common in cats with HCM from a rehoming center study sample. Lower left atrial systolic function appears to precede overt HCM.

The Use of 3-D Models of Echocardiographic Imaging Planes for Teaching Echocardiography Techniques for Use in Dogs and Cats.

Echocardiography is an invaluable technique for the diagnosis of heart disease. The aim of this study was to develop 3-D models of healthy and diseased hearts of dogs and cats, and to evaluate their effectiveness in assisting veterinary undergraduates to understand echocardiographic imaging planes. Resin models depicting the main echocardiographic imaging planes of normal hearts were created, as well as example hearts with features of mitral degeneration in dogs and hypertrophic cardiomyopathy in cats. After a theoretical class, fourth-year students were randomly assigned to one of two groups (model group or control group). The model group had access to the 3-D models, along with self-explanatory text about echocardiographic imaging planes; the control group only had access to the self-explanatory text. Both groups were allowed 2weeks to study their allocated resources, after which the students undertook an assessment to evaluate their learning and completed a questionnaire about their experiences and satisfaction with the respective teaching method. A total of 39 students participated in the study, 19 in the model group and 20 in the control group. Students assigned to the model group spent more time studying (p = 0.0027). The proportion of students who achieved a satisfactory grade in the assessment was 89.5% in the model group and 60% in the control group (p = 0.0449). The 3-D models facilitated, and significantly improved, the identification of cardiac structures and disease-associated abnormalities, and the learning process in general. Additionally, the models seemed to provide greater student motivation for studying echocardiography.

Prognostic criteria for assessing of hypertrophic cardiomyopathy in cats

Hypertrophic cardiomyopathy (HCM) occurs in 10-15% of cats in the population [5, 7]. Cardiomyopathy is a myocardial disease in which the structure and function of the heart muscle are impaired in the absence of any other condition that could cause the observed deviation [10]. To assess the state of the cardiovascular system, echocardiography, electrocardiography, X-ray examination, as well as, importantly, physical examination are used in veterinary cardiology [1, 4, 5, 10]. Visual diagnostic techniques are the most objective and informative, however, it is the components of the physical examination and the timely response of the owner to deviations in the parameters of the physical examination that allows you to select and evaluate the effectiveness of the treatment of heart disease. Counting the number of respiratory movements at rest (during sleep) is one of the important criteria for physical examination available to the cat owner [9]. This indicator allows you to adjust the treatment, as well as predict the possible onset of deterioration. The aim of the presented study was to determine the main prognostic parameters in cats with congestive heart failure caused by HCMP stage C [10]. A group of 4 DSH cats was formed, in which hypertrophic cardiomyopathy stage C was detected (according to ACVIM staging). When assessing the main indicators, it was revealed that unfavorable prognostic signs are the diameter of the left atrium (correlation degree -0.62), the number of respiratory movements at rest - both before and after the start of treatment (correlation degree -0.77 and -0.81, respectively). It should also be noted a moderate positive correlation between the indicator of life expectancy and the fraction of contractility of the left atrium (0.39). However, it should be noted that in order to more accurately determine the diagnostic significance and the possibility of determining forecasts, it is necessary to increase the number of animal samples with an assessment of indicators in dynamics.

Ambulatory electrocardiography, heart rate variability, and pharmacologic stress testing in cats with subclinical hypertrophic cardiomyopathy

The utility of ambulatory electrocardiography (AECG) to evaluate cats with subclinical hypertrophic cardiomyopathy (HCM) for arrhythmias and heart rate variability (HRV) is not well defined but may provide information regarding risk stratification. This prospective study used AECG to evaluate ectopy and HRV in subclinical HCM cats compared to healthy controls and is the first to implement a pharmacologic cardiac stress test. Twenty-three purpose-bred, Maine coon cross cats (16 HCM, 7 control) underwent 48-h of continuous AECG. Terbutaline (0.2–0.3 mg/kg) was administered orally at 24 and 36 h. Heart rate, ectopy frequency and complexity and HRV parameters, including standard deviation of normal R-R intervals (SDNN), were compared pre-terbutaline and post-terbutaline and across phenotype, genotype and sex. Genotype for an HCM-causative mutation was significantly associated with the frequency of supraventricular (P = 0.033) and ventricular (P = 0.026) ectopy across all cats. Seven HCM cats and zero healthy cats had a sinus arrhythmia. Mean heart rate was significantly higher post-terbutaline (p < 0.0001). HCM cats had significantly greater HRV compared to controls (SDNN: p = 0.0006). Male cats had significantly higher HRV (SDNN: p = 0.0001) and lower mean heart rates (p = 0.0001). HRV decreased post-terbutaline (SDNN: p = 0.0008) and changes in HRV observed between sexes were attenuated by terbutaline.

Prevalence of cardiac myosin-binding protein C3 mutations in Maine Coon cats with hypertrophic cardiomyopathy.

Background and Aim:Hypertrophic cardiomyopathy (HCM) is a common heart problem that affects many cats. Although cats with HCM are symptomatic, some die suddenly or develop congestive heart failure. Therefore, this study aimed to estimate the prevalence of myosin-binding protein C3 (MYBPC3), A31P, and A74T polymorphisms in Maine Coon cats to assess risk factors for diagnosing HCM in cats.Materials and Methods:Forty-nine Maine Coon cats of at least 10 months of age were enrolled in this study. First, clinical parameters, such as heart rate, systolic blood pressure, and echocardiography, were evaluated. Then, polymerase chain reaction, followed by DNA sequencing, was conducted using specific primers for amino acid substitutions caused by genetic variants of MYBPC3-A31P and -A74T polymorphisms.Results:Investigations showed that the prevalence of MYBPC3-A31P and -A74T mutations in this study was 16.33% and 24.45%, respectively. Moreover, HCM in cats with MYBPC3-A31P and A74T mutations increased with age, body weight, high heart rate, and prolonged isovolumic relaxation time.Conclusion:Therefore, we propose that Maine Coon cats develop HCM due to multiple genetic factors and underlying clinical characteristics in individual cats. Furthermore, relaxation time assessments can be a sensitive technique for HCM screening during its preclinical phase and can help identify the risk of developing HCM. However, further studies are warranted to evaluate the effect of MYBPC3 mutations on the phenotypic expression of HCM.

Methods for diagnosing of hypertrophic cardiomyopathy in cats

The article discusses the main diagnostic methods used in the diagnosis of hypotrophic cardiomyopathy in cats. The work was carried out on the basis of one of the veterinary clinics in St. Petersburg. Of the clinical symptoms, the most common are shortness of breath, cyanosis, weakness, breathing through the mouth. Systemic hypertension was diagnosed in sick cats. In hypertrophic cardiomyopathy of cats, echocardiography is still the gold standard of diagnosis, but it is worth noting that for an accurate diagnosis, one should not be limited to ultrasound examination of the heart, a comprehensive assessment of the clinical status of the animal should be carried out and the degree of negative effect of HCM on a particular patient should be determined.

Analysis of the Serum Peptidomics Profile for Cats With Sarcomeric Gene Mutation and Hypertrophic Cardiomyopathy.

Background: Hypertrophic cardiomyopathy (HCM) has a complex phenotype that is partly explained by genetic variants related to this disease. The serum peptidome profile is a promising approach to define clinically relevant biomarkers. This study aimed to classify peptide patterns in serum samples between cats with sarcomeric gene mutations and normal cats.Materials and Methods: In the total serum samples from 31 cats, several essential proteins were identified by peptidomics analysis. The 5,946 peptides were differentially expressed in cats with sarcomeric gene mutations compared with cats without mutations.Results: Our results demonstrated characteristic protein expression in control cats, Maine Coon cats, and Maine Coon cats with gene mutations. In cats with gene mutations, peptide expression profiling showed an association with three peptides, Cytochrome 3a132 (CYP3A132), forkhead box O1 (FOXO1), and ArfGAP, with GTPase domains, ankyrin repeats, and PH domain 2 (AGAP2).Discussion: The serum peptidome of cats with mutations might provide supporting evidence for the dysregulation of metabolic and structural proteins. Genetic and peptidomics investigations may help elucidate the phenotypic variability of HCM and treatment targets to reduce morbidity and mortality of HCM in cats.

The Feline Cardiomyopathies: 3. Cardiomyopathies other than HCM

Practical relevance:Although feline hypertrophic cardiomyopathy (HCM) occurs more commonly, dilated cardiomyopathy (DCM), restrictive cardiomyopathy (RCM), arrhythmogenic right ventricular cardiomyopathy (ARVC), left ventricular noncompaction (LVNC) and cardiomyopathy – nonspecific phenotype (NCM; formerly unclassified cardiomyopathy) are all recognized in domestic cats.Patient group:Any adult domestic cat, of either sex and of any breed, can be affected.Diagnostics:The non-HCM cardiomyopathies are rarely suspected in subclinically affected cats, so most are first identified when a cat presents with signs of heart failure or systemic thromboembolic disease. The definitive clinical confirmatory test for these other feline cardiomyopathies is echocardiography.Key findings:‘Cardiomyopathy – nonspecific phenotype’ is a catch-all term that groups hearts with myocardial changes that either do not meet the criteria for any one type of cardiomyopathy (HCM, RCM, DCM, ARVC, LVNC) or meet the echocardiography criteria for more than one type. RCM is characterized by diastolic dysfunction due to fibrosis that results in a restrictive transmitral flow pattern on Doppler echocardiography and usually marked left or biatrial enlargement. DCM is characterized by decreased myocardial contractility and is rare in cats. When it occurs, it is seldom due to taurine deficiency. However, since taurine-deficient DCM is usually reversible, a diet history should be obtained, whole blood and plasma taurine levels should be measured and taurine should be supplemented in the diet if the diet is not commercially manufactured. ARVC should be suspected in adult cats with severe right heart enlargement and right heart failure (ascites and/or pleural effusion), especially if arrhythmia is present. Feline LVNC is rare; its significance continues to be explored. Treatment of the consequences of these cardiomyopathies (management of heart failure, thromboprophylaxis, treatment of systemic arterial thromboembolism) is the same as for HCM.Conclusions:While these other cardiomyopathies are less prevalent than HCM in cats, their clinical and radiographic presentation is often indistinguishable from HCM. Echocardiography is usually the only ante-mortem method to determine which type of cardiomyopathy is present. However, since treatment and prognosis are often similar for the feline cardiomyopathies, distinguishing among the cardiomyopathies is often not essential for determining appropriate therapy.Areas of uncertainty:The feline cardiomyopathies do not always fit into one distinct category. Interrelationships among cardiomyopathies in cats may exist and understanding these relationships in the future might provide critical insights regarding treatment and prognosis.

172 A genome wide association study of hypertrophic cardiomyopathy in cats

172 A genome wide association study of hypertrophic cardiomyopathy in cats

Cardiac extracellular volume fraction in cats with preclinical hypertrophic cardiomyopathy.

BackgroundCardiac magnetic resonance imaging (CMR) allows for detection of fibrosis in hypertrophic cardiomyopathy (HCM) by quantification of the extracellular volume fraction (ECV).Hypothesis/ObjectivesTo quantify native T1 mapping and ECV in cats. We hypothesize that native T1 mapping and ECV will be significantly increased in HCM cats compared with healthy cats.AnimalsSeventeen healthy and 12 preclinical HCM, age‐matched, client‐owned cats.MethodsProspective observational study. Tests performed included indirect blood pressure, CBC, biochemical analysis including total thyroid, urinalysis, transthoracic echocardiogram, and CMR. Cats were considered healthy if all tests were within normal limits and a diagnosis of HCM was determined by the presence of left ventricular concentric hypertrophy ≥6 mm on echocardiography.ResultsThere were statistically significant differences in LV mass (healthy = 5.87 g, HCM = 10.3 g, P < .0001), native T1 mapping (healthy = 1122 ms, HCM = 1209 ms, P = .004), and ECV (healthy = 26.0%, HCM = 32.6%, P < .0001). Variables of diastolic function including deceleration time of early diastolic transmitral flow (DTE), ratio between peak velocity of early diastolic transmitral flow and peak velocity of late diastolic transmitral flow (E : A), and peak velocity of late diastolic transmitral flow (A wave) were significantly correlated with ECV (DTE; r = 0.73 P = .007, E : A; r = −0.75 P = .004, A wave; r = 0.76 P = .004).Conclusions and Clinical ImportanceQuantitative assessment of cardiac ECV is feasible and can provide additional information not available using echocardiography.

A Novel Homozygous Intronic Variant in TNNT2 Associates With Feline Cardiomyopathy.

BackgroundHypertrophic cardiomyopathy (HCM) is a genetic disease of the heart and the most common cause of sudden cardiac death in the young. HCM is considered a disease of the sarcomere owing to the large number of mutations in genes encoding sarcomeric proteins. The riddle lies in discovering how these mutations lead to disease. As a result, treatments to prevent and/or treat HCM are limited to invasive surgical myectomies or ablations. The A31P variant of cardiac myosin binding protein-C, encoded by MYBPC3, was found to be more prevalent in a cohort of Maine Coon cats with HCM. However, other mutations in MYBPC3 and MYH7 have also been associated with HCM in cats of other breeds. In this study, we expand the spectrum of genes associated with HCM in cats.ResultsNext Generation Whole Genome sequencing was performed using DNA isolated from peripheral blood of a Maine Coon with cardiomyopathy that tested negative for the MYBPC3 A31P variant. Through risk stratification of variants, we identified a novel, homozygous intronic variant in cardiac troponin T (TNNT2). In silico analysis of the variant suggested that it may affect normal splicing of exon 3 of TNNT2. Both parents tested heterozygous for the mutation, but were unaffected by the disease. Echocardiography analyses revealed that the proband had shown early onset congestive heart failure, which is managed with a treatment regime including ACE and aldosterone inhibitors.ConclusionIn summary, we are the first to demonstrate the association between TNNT2 mutations and HCM in felines, suggesting that this gene should be included in the testing panel of genes when performing genetic testing for HCM in cats.

Assessment of left atrial function in feline hypertrophic cardiomyopathy by using two- dimensional speckle tracking echocardiography

BackgroundLeft atrial (LA) function plays an important role in diastolic dysfunction in cats with hypertrophic cardiomyopathy (HCM). Two-dimensional speckle tracking echocardiography (2D-STE) is a technique for assessing LA function. This study aimed to evaluate the LA function in HCM cats compared to normal cats, using 2D-STE.ResultsSeventeen client-owned cats affected with HCM and twenty healthy control cats were studied. Conventional echocardiographic and 2D-STE variables were measured and compared between groups (control and HCM groups). Variability of the peak atrial longitudinal strain (PALS) displayed good reproducibility with 4.7% intra-observer and 14% inter-observer repeatability. The mean value of PALS in the HCM group (13.16 ± 8.64) was lower than that in the control group (28.54 ± 10.31) (P < 0.001). PALS was lowest in the LA roof region. The atrial longitudinal strains of septal and lateral regions were significantly lower in the HCM group than in the normal group. The PALS correlated with the percentage of the LA fractional shortening (LA-FS) (r = 0.538, P = 0.001), the percentage of the LA ejection fraction (LA-EF) (r = 0.797, P < 0.001), and the LA fractional area change (FAC) (r = 0.746, P < 0.001).ConclusionsPALS is a feasible and reproducible method to evaluate the LA function in cats affected with HCM.

A comprehensive review of hypertrophic cardiomyopathy and arterial thromboembolism in cats

The number of cats requiring treatment for hypertrophic cardiomyopathy (HCM) and arterial thromboembolism (ATE) continues to increase, and the knowledge regarding its management is constantly evolving. The pathological lesions of HCM include hypertrophy of the left ventricle, which causes abnormalities in the relaxation function of the heart. This phenomenon increases the stiffness of the ventricular muscle, thereby reducing the ability of the left ventricle to fill with blood during diastole. This is accompanied by an increase in ventricular filling pressure and left atrial pressure. HCM in cats is characterized by concentric hypertrophy and atrial enlargement. Hypertrophic obstructive cardiomyopathy (HOCM) also involves a narrowed left ventricular outflow tract, and in humans, it is generally perceived to be a more serious disease. However, unlike in humans, HCM and HOCM in cats do not result in significantly different survival times. Heart murmurs, gallop rhythms, arrhythmias, cardiac hypertrophy, congestive heart failure (CHF), ATE, and cardiac sudden death (CSD) have all been associated with HCM. Although the presence of a heart murmur is a characteristic feature of heart disease, it may be a functional one, which is defined as “dynamic right ventricular outflow track obstruction” (DRVOTO) in cats. Therefore, it is difficult to evaluate the presence of HCM based on the existence of a heart murmur alone. ATE typically affects one or both hind limbs, resulting in acute paralysis and severe pain, consistent with lower motor neuron disease. The clot, which is formed in the left atrium of the heart, travels to an artery and becomes an ATE, which then blocks the blood flow and impairs circulation, causing infarction. Therefore, ATE in cats is a serious condition. This review describes the results of the latest research on HCM and ATE, the most common heart conditions in cats.

Cardiac Effects of a Single Dose of Pimobendan in Cats With Hypertrophic Cardiomyopathy; A Randomized, Placebo-Controlled, Crossover Study.

Background: Pimobendan has been shown to impart a significant survival benefit in cardiomyopathic cats who receive it as part of heart failure therapy. However, use of pimobendan remains controversial in cats with hypertrophic cardiomyopathy (HCM) due to lack of pharmacodynamic data for pimobendan in cats with HCM and due to theoretical concerns for exacerbating left ventricular outflow tract obstructions.Hypothesis/Objectives: Our objective was to investigate the cardiac effects of pimobendan in cats with HCM. We hypothesized that pimobendan would not exacerbate left ventricular outflow tract obstructions and that it would improve echocardiographic measures of diastolic function.Animals: Thirteen purpose-bred cats were studied from a research colony with naturally-occurring HCM due to a variant in myosin binding protein C.Methods: Cats underwent two examinations 24 h apart with complete standard echocardiography. On their first day of evaluation, they were randomized to receive oral placebo or 1.25 mg pimobendan 1 h prior to exam. On their second examination, they were crossed over and received the remaining treatment. Investigators were blinded to all treatments.Results: The pimobendan group had a significant increase in left atrial fractional shortening (pimobendan group 41.7% ± 5.9; placebo group 36.1% ± 6.0; p = 0.04). There was no significant difference in left ventricular outflow tract (LVOT) velocities between the groups (pimobendan group 2.8 m/s ± 0.8; placebo group 2.6 m/s ± 1.0). There were no significant differences between the number of cats with LVOT obstructions between groups (12 in pimobendan group; 11 in placebo group; p = 1.00). There were no detectable differences in any systolic measures, including left ventricular fractional shortening, mitral annular plane systolic excursion, and tricuspid annular plane systolic excursion. Doppler-based diastolic function assessment was precluded by persistent tachycardia.Conclusions: Improved left atrial function in the pimobendan group could explain some of the reported survival benefit for HCM cats in CHF. Pimobendan did not exacerbate LVOT obstructions and thus may not be contraindicated in HCM cats with LVOT obstructions. Future studies are needed to better characterize other physiologic effects, particularly regarding diastolic function assessment, and to better assess safety of pimobendan over a longer time-course.