This report, issued by the ACVIM Specialty of Cardiology consensus panel, revises guidelines for the diagnosis and treatment of myxomatous mitral valve disease (MMVD, also known as endocardiosis and degenerative or chronic valvular heart disease) in dogs, originally published in 2009. Updates were made to diagnostic, as well as medical, surgical, and dietary treatment recommendations. The strength of these recommendations was based on both the quantity and quality of available evidence supporting diagnostic and therapeutic decisions. Management of MMVD before the onset of clinical signs of heart failure has changed substantially compared with the 2009 guidelines, and new strategies to diagnose and treat advanced heart failure and pulmonary hypertension are reviewed.

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A spontaneously occurring disease of domestic cats was identified by echocardiography and was similar in its phenotypic expression to HCM in humans; it was characterized by unexplained left ventricular hypertrophy in a variety of patterns with or without evidence of outflow obstruction. Unfavorable prognosis was associated with greater magnitude of hypertrophy and absence of outflow obstruction. Feline HCM may prove to be a valuable animal model of the human disease.

BackgroundPimobendan is effective in treatment of dogs with congestive heart failure (CHF) secondary to myxomatous mitral valve disease (MMVD). Its effect on dogs before the onset of CHF is unknown.Hypothesis/ObjectivesAdministration of pimobendan (0.4–0.6 mg/kg/d in divided doses) to dogs with increased heart size secondary to preclinical MMVD, not receiving other cardiovascular medications, will delay the onset of signs of CHF, cardiac‐related death, or euthanasia.Animals360 client‐owned dogs with MMVD with left atrial‐to‐aortic ratio ≥1.6, normalized left ventricular internal diameter in diastole ≥1.7, and vertebral heart sum >10.5.MethodsProspective, randomized, placebo‐controlled, blinded, multicenter clinical trial. Primary outcome variable was time to a composite of the onset of CHF, cardiac‐related death, or euthanasia.ResultsMedian time to primary endpoint was 1228 days (95% CI: 856–NA) in the pimobendan group and 766 days (95% CI: 667–875) in the placebo group (P = .0038). Hazard ratio for the pimobendan group was 0.64 (95% CI: 0.47–0.87) compared with the placebo group. The benefit persisted after adjustment for other variables. Adverse events were not different between treatment groups. Dogs in the pimobendan group lived longer (median survival time was 1059 days (95% CI: 952–NA) in the pimobendan group and 902 days (95% CI: 747–1061) in the placebo group) (P = .012).Conclusions and Clinical ImportanceAdministration of pimobendan to dogs with MMVD and echocardiographic and radiographic evidence of cardiomegaly results in prolongation of preclinical period and is safe and well tolerated. Prolongation of preclinical period by approximately 15 months represents substantial clinical benefit.

Consensus Statements of the American College of Veterinary Internal Medicine (ACVIM) provide the veterinary community with up-to-date information on the pathophysiology, diagnosis, and treatment of clinically important animal diseases. The ACVIM Board of Regents oversees selection of relevant topics, identification of panel members with the expertise to draft the statements, and other aspects of assuring the integrity of the process. The statements are derived from evidence-based medicine whenever possible and the panel offers interpretive comments when such evidence is inadequate or contradictory. A draft is prepared by the panel, followed by solicitation of input by the ACVIM membership that may be incorporated into the statement. It is then submitted to the Journal of Veterinary Internal Medicine, where it is edited before publication. The authors are solely responsible for the content of the statements. AbstractCardiomyopathies are a heterogeneous group of myocardial disorders of mostly unknown etiology, and they occur commonly in cats. In some cats, they are welltolerated and are associated with normal life expectancy, but in other cats they can result in congestive heart failure, arterial thromboembolism or sudden death.Cardiomyopathy classification in cats can be challenging, and in this consensus statement we outline a classification system based on cardiac structure and function (phenotype). We also introduce a staging system for cardiomyopathy that includes subdivision of cats with subclinical cardiomyopathy into those at low risk

Background-Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary familial heart muscle disease associated with substantial cardiovascular morbidity and risk of sudden death. Efforts to discern relevant pathophysiological mechanisms have been impaired by lack of a suitable animal model. Methods and Results-ARVC was diagnosed in 23 boxer dogs (12 male; 9.1Ϯ2.3 years old). Clinical events alone or in combination included sudden death (nϭ9; 39%), ventricular arrhythmias of suspected right ventricular (RV) origin (nϭ19; 83%), syncope (nϭ12, 52%), and heart failure (nϭ3; 13%). Right ventricular enlargement or aneurysms occurred in 10 (43%). Striking histopathological abnormalities were present in each boxer dog but not in controls, including severe RV myocyte loss with replacement by fatty (nϭ15, 65%) or fibrofatty (nϭ8, 35%) tissue. Focal fibrofatty lesions were also present in both atria (nϭ8) and the left ventricle (LV) (nϭ11). Fatty replacement occupied substantially greater RV wall area in ARVC dogs than controls (40.4Ϯ18.8% versus 13.8Ϯ3.4%, respectively) (PϽ0.001); residual myocardium was correspondingly reduced (56.6Ϯ19.2% versus 84.8Ϯ3.8% in controls) (PϽ0.001). MRI demonstrated bright anterolateral and/or infundibular RV myocardial signals, confirmed as fat by histopathology. Myocarditis appeared in the RV (nϭ14, 61%) and LV (nϭ16, 70%) and in each dog with sudden death, but not in controls. Familial transmission was evident in 10 of the 23. Key Words: models, animal Ⅲ cardiomyopathy Ⅲ pathology Ⅲ death, sudden A rrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary familial cardiomyopathy associated with substantial cardiovascular morbidity and sudden death in the young. 1-3 ARVC is transmitted as an autosomal dominant trait, and 2 mutations have been identified at the cardiac ryanodine receptor 2 gene (ARVD2) and the desmoplakin gene (ARVD8). 4,5 It has been noted for many years that the boxer canine breed is predisposed to ventricular arrhythmias and sudden death, 6,7 but the underlying disease responsible for these clinical features has been incompletely defined. In light of advances in genomic mapping of the domestic dog, 8 a spontaneous canine model of ARVC and sudden death would provide a unique opportunity to study this disease genome and contribute valuable insights into its pathogenesis. Therefore, the purpose of the present study was to define the clinical and pathological features of a naturally occurring myocardial disease in boxer dogs and assess its suitability as an animal model of ARVC. Conclusions-We Methods Selection of Animal SubjectsAs part of an ongoing study to evaluate the heritability of ventricular arrhythmias in boxer dogs, 239 such animals, including 6 large families, were prospectively recruited for Holter ECG between 1997 and 1999 at the Ohio State University College of Veterinary Medicine. Of those with substantial ectopy or syncope that died or were euthanized, 23 boxer dogs (12 male, 11 female) had autopsy examination and constitute the study group....

BackgroundHypertrophic cardiomyopathy is the most prevalent heart disorder in cats and principal cause of cardiovascular morbidity and mortality. Yet, the impact of preclinical disease is unresolved.Hypothesis/ObjectivesObservational study to characterize cardiovascular morbidity and survival in cats with preclinical nonobstructive (HCM) and obstructive (HOCM) hypertrophic cardiomyopathy and in apparently healthy cats (AH).AnimalsOne thousand seven hundred and thirty client‐owned cats (430 preclinical HCM; 578 preclinical HOCM; 722 AH).MethodsRetrospective multicenter, longitudinal, cohort study. Cats from 21 countries were followed through medical record review and owner or referring veterinarian interviews. Data were analyzed to compare long‐term outcomes, incidence, and risk for congestive heart failure (CHF), arterial thromboembolism (ATE), and cardiovascular death.ResultsDuring the study period, CHF, ATE, or both occurred in 30.5% and cardiovascular death in 27.9% of 1008 HCM/HOCM cats. Risk assessed at 1, 5, and 10 years after study entry was 7.0%/3.5%, 19.9%/9.7%, and 23.9%/11.3% for CHF/ATE, and 6.7%, 22.8%, and 28.3% for cardiovascular death, respectively. There were no statistically significant differences between HOCM compared with HCM for cardiovascular morbidity or mortality, time from diagnosis to development of morbidity, or cardiovascular survival. Cats that developed cardiovascular morbidity had short survival (mean ± standard deviation, 1.3 ± 1.7 years). Overall, prolonged longevity was recorded in a minority of preclinical HCM/HOCM cats with 10% reaching 9‐15 years.Conclusions and Clinical ImportancePreclinical HCM/HOCM is a global health problem of cats that carries substantial risk for CHF, ATE, and cardiovascular death. This finding underscores the need to identify therapies and monitoring strategies that decrease morbidity and mortality.

Results suggested that serum NT-proBNP concentration may be a useful adjunct clinical test for diagnosing cardiac disease in dogs and assessing the severity of disease in dogs with cardiac disease.