Background
Pimobendan 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/Objectives
Administration 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.

Animals
360 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.

Methods
Prospective, 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.

Results
Median 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 Importance
Administration 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.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/jvim.14586

Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study - A Randomized Clinical Trial

Pulmonary hypertension (PH), defined by increased pressure within the pulmonary vasculature, is a hemodynamic and pathophysiologic state present in a wide variety of cardiovascular, respiratory, and systemic diseases. The purpose of this consensus statement is to provide a multidisciplinary approach to guidelines for the diagnosis, classification, treatment, and monitoring of PH in dogs. Comprehensive evaluation including consideration of signalment, clinical signs, echocardiographic parameters, and results of other diagnostic tests supports the diagnosis of PH and allows identification of associated underlying conditions. Dogs with PH can be classified into the following 6 groups: group 1, pulmonary arterial hypertension; group 2, left heart disease; group 3, respiratory disease/hypoxia; group 4, pulmonary emboli/pulmonary thrombi/pulmonary thromboemboli; group 5, parasitic disease (Dirofilaria and Angiostrongylus); and group 6, disorders that are multifactorial or with unclear mechanisms. The approach to treatment of PH focuses on strategies to decrease the risk of progression, complications, or both, recommendations to target underlying diseases or factors contributing to PH, and PH-specific treatments. Dogs with PH should be monitored for improvement, static condition, or progression, and any identified underlying disorder should be addressed and monitored simultaneously.

/pdf/acvim-consensus-statement-guidelines-for-the-diagnosis-2eh8tayjgd.pdf

ACVIM consensus statement guidelines for the diagnosis, classification, treatment, and monitoring of pulmonary hypertension in dogs

Background Broadly applicable reference intervals (RIs) for measurements of left atrial (LA) and left ventricular (LV) size and function generated prospectively using statistically appropriate methods are limited. Objectives To generate body size-independent RIs for linear, area, and volume measurements of LA size and LV size and function. Animals Healthy adult dogs (n = 122) of variable size and somatotype. Methods Prospective study. All dogs underwent an echocardiogram performed by the same examiner. Effects of body weight, sex, age, and heart rate were evaluated by regression and correlation analyses. Scaling exponents and prediction intervals were generated for linear measurements using the allometric equation. After normalization to body weight, 95% RIs were determined using nonparametric methods with 2.5 and 97.5 percentiles serving as the lower and upper limits (each with 90% confidence intervals), respectively. Results Linear LA and LV measurements were strongly correlated (R2 ≥ 0.79) with body weight. Scaling exponents were close to the expected 1/3 (0.299-0.392). Prediction intervals for linear measurements of LV chamber size were considerably narrower than previously reported. Weak correlations (r = -0.42 to -0.50) among LV fractional shortening, fractional area change, and ejection fraction and body weight were identified. No other meaningful relationships were identified between the measurements and sex, age, and heart rate. Conclusions and clinical importance Body size-independent RIs for several linear, area, and volume measurements of LA and LV size and function were generated prospectively from a large and diverse reference population and are available for clinical use.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/jvim.15562

Echocardiographic quantitation of left heart size and function in 122 healthy dogs: A prospective study proposing reference intervals and assessing repeatability.

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

BACKGROUND: Myxomatous mitral valve disease (MMVD) is an important cause of morbidity and mortality in dogs.
OBJECTIVES: To compare, throughout the period of follow-up of dogs that had not yet reached the primary endpoint, the longitudinal effects of pimobendan versus benazepril hydrochloride treatment on quality-of-life (QoL) variables, concomitant congestive heart failure (CHF) treatment, and other outcome variables in dogs suffering from CHF secondary to MMVD.
ANIMALS: A total of 260 dogs in CHF because of MMVD.
METHODS: A prospective single-blinded study with dogs randomized to receive pimobendan (0.4-0.6 mg/kg/day) or benazepril hydrochloride (0.25-1.0 mg/kg/day). Differences in outcome variables and time to intensification of CHF treatment were compared.
RESULTS: A total of 124 dogs were randomized to pimobendan and 128 to benazepril. No difference was found between groups in QoL variables during the trial. Time from inclusion to 1st intensification of CHF treatment was longer in the pimobendan group (pimobendan 98 days, IQR 30-276 days versus benazepril 59 days, IQR 11-121 days; P = .0005). Postinclusion, dogs in the pimobendan group had smaller heart size based on VHS score (P = .013) and left ventricular diastolic (P = .035) and systolic (P = .0044) dimensions, higher body temperature (P = .030), serum sodium (P = .0027), and total protein (P = .0003) concentrations, and packed cell volume (P = .030). Incidence of arrhythmias was similar in treatment groups.
CONCLUSIONS AND CLINICAL IMPORTANCE: Pimobendan versus benazepril resulted in similar QoL during the study, but conferred increased time before intensification of CHF treatment. Pimobendan treatment resulted in smaller heart size, higher body temperature, and less retention of free water.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1111/jvim.12181

Longitudinal analysis of quality of life, clinical, radiographic, echocardiographic, and laboratory variables in dogs with myxomatous mitral valve disease receiving Pimobendan or Benazepril: the QUEST study

Background
The benefit of pimobendan in delaying the progression of preclinical dilated cardiomyopathy (DCM) in Dobermans is not reported

Hypothesis
That chronic oral administration of pimobendan to Dobermans with preclinical DCM will delay the onset of CHF or sudden death and improve survival

Animals
Seventy-six client-owned Dobermans recruited at 10 centers in the UK and North America

Methods
The trial was a randomized, blinded, placebo-controlled, parallel group multicenter study Dogs were allocated in a 1:1 ratio to receive pimobendan (Vetmedin capsules) or visually identical placebo

The composite primary endpoint was prospectively defined as either onset of CHF or sudden death Time to death from all causes was a secondary endpoint

Results
The proportion of dogs reaching the primary endpoint was not significantly different between groups (P = 1) The median time to the primary endpoint (onset of CHF or sudden death) was significantly longer in the pimobendan (718 days, IQR 441–1152 days) versus the placebo group (441 days, IQR 151–641 days) (log-rank P = 00088) The median survival time was significantly longer in the pimobendan (623 days, IQR 491–1531 days) versus the placebo group (466 days, IQR 236–710 days) (log-rank P = 034)

Conclusion and Clinical Importance
The administration of pimobendan to Dobermans with preclinical DCM prolongs the time to the onset of clinical signs and extends survival Treatment of dogs in the preclinical phase of this common cardiovascular disorder with pimobendan can lead to improved outcome

http://www.midland-dobermann-club.co.uk/jvim10261.pdf

Efficacy of Pimobendan in the prevention of congestive heart failure or sudden death in Doberman Pinschers with preclinical dilated cardiomyopathy (The PROTECT Study)

Prospective evaluation of the combined value of physical examination and biomarker variables in screening for preclinical dilated cardiomyopathy in Doberman Pinschers.

L Braz-Ruivo

Papers

Efficacy of Pimobendan in the prevention of congestive heart failure or sudden death in Doberman Pinschers with preclinical dilated cardiomyopathy (The PROTECT Study)

Prospective evaluation of the combined value of physical examination and biomarker variables in screening for preclinical dilated cardiomyopathy in Doberman Pinschers.