Effect of pimobendan on left atrial function: an echocardiographic pilot study in 11 healthy cats

Toaldo, Marco Baron; Pollesel, Marta; Diana, Alessia

doi:10.1016/j.jvc.2020.02.002

Cited by 11 publications

(9 citation statements)

References 35 publications

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“…Multivariate analysis identified a stronger effect of pimobendan on variables of LA function in cats with HCM compared to apparently healthy cats considering 5 echocardiographic indices: LA FS, A VTI, LAapp peak, LA kinetic energy, and LA ejection force. Similar to previously reported data, 33,39 an increase in LA FS occurred after pimobendan in cats with HCM, with LA FS used as an important functional marker of LA function as reported elsewhere. 11,20,27 Decreased LA FS has been identified as an independent predictor of prognosis 27 and, more specifically, 2-year mortality risk associated with ATE, 11 in cats with HCM.…”

Section: T a B L E 1 Baseline Characteristics Of The Cats In Each Tresupporting

confidence: 89%

“…Based on pharmacokinetic studies in healthy cats 27,32 twice daily dosing has been recommended 27,32 . Data on the positive inotropic effect to the left ventricle have been well‐established in dogs 34‐37 but rarely studied in cats, 38 and limited data are available on its effect on LA function in cats with cardiomyopathy 10,31,33,39 …”

Section: Introductionmentioning

confidence: 99%

“…27,32 Data on the positive inotropic effect to the left ventricle have been well-established in dogs [34][35][36][37] but rarely studied in cats, 38 and limited data are available on its effect on LA function in cats with cardiomyopathy. 10,31,33,39 Our primary hypothesis was that pimobendan would improve LA transport function as determined by echocardiography in apparently healthy cats and cats with HCM. Secondary objectives were to compare effect size of pimobendan on LA function in cats with HCM vs healthy cats and to determine whether or not the effect of pimobendan on LA function in cats with LA enlargement differs from that in cats with normal LA size.…”

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confidence: 99%

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Effects of pimobendan on left atrial transport function in cats

Kochie

Schober

Rhinehart

et al. 2020

Veterinary Internal Medicne

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Background Arterial thromboembolism is a sequela of hypertrophic cardiomyopathy (HCM) in cats related to left atrial (LA) enlargement and dysfunction. Hypothesis Pimobendan improves LA transport function in cats. Animals Twenty‐two client‐owned cats with HCM and 11 healthy cats. Methods Prospective, double‐blind, randomized, placebo‐controlled clinical cohort study. Cats were randomized to receive either pimobendan (0.25 mg/kg PO q12h) or placebo for 4 to 7 days. Nineteen echocardiographic variables of LA size and function were evaluated. Statistical comparisons included t tests, analysis of variance, and multivariable analyses. Results Peak velocity of left auricular appendage flow (LAapp peak; mean ± SD, 0.85 ± 0.20 vs 0.71 ± 0.22 m/s; P = .01), maximum LA volume (P = .03), LA total emptying volume (P = .03), peak velocity of late diastolic transmitral flow (A peak velocity; 0.77 ± 0.12 vs 0.62 ± 0.17 m/s; P = .05), and A velocity time integral (A VTI; 3.05 ± 0.69 vs 3.37 ± 0.49; P = .05) were increased after pimobendan. Mean change after pimobendan was larger in cats with HCM compared to healthy cats for LA fractional shortening (2.1% vs −2.1%; P = .05), A VTI (0.58 vs 0.01 cm; P = .01), LAapp peak (0.20 vs 0.02 m/s; P = .02), LA kinetic energy (3.51 vs −0.10 kdynes‐cm; P = .05), and LA ejection force (1.93 vs −0.07 kdynes; P = .01) in the multivariable model. The stronger effect of pimobendan in cats with HCM was independent of LA size. Conclusions and Clinical Importance We identified positive, albeit minor, effects of pimobendan on LA function in cats with HCM. Whether or not treatment with pimobendan decreases the risk of cardiogenic embolism deserves further study.

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Section: T a B L E 1 Baseline Characteristics Of The Cats In Each Tresupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Effects of pimobendan on left atrial transport function in cats

Kochie

Schober

Rhinehart

et al. 2020

Veterinary Internal Medicne

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“…Pimobendan does have the potential ability to improve diastolic function (in dogs) and it has been suggested that it may improve systolic LA function, again for a short time (<3 h) in cats. [194][195][196] Both could result in clinical and hemodynamic improvement in a cat in heart failure due to HCM.…”

Section: Pimobendanmentioning

confidence: 99%

The Feline Cardiomyopathies: 2. Hypertrophic cardiomyopathy

Kittleson

Côté

2021

Journal of Feline Medicine and Surgery

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Practical relevance: Hypertrophic cardiomyopathy (HCM) is the most common form of feline cardiomyopathy observed clinically and may affect up to approximately 15% of the domestic cat population, primarily as a subclinical disease. Fortunately, severe HCM, leading to heart failure or arterial thromboembolism (ATE), only occurs in a small proportion of these cats. Patient group: Domestic cats of any age from 3 months upward, of either sex and of any breed, can be affected. A higher prevalence in male and domestic shorthair cats has been reported. Diagnostics: Subclinical feline HCM may or may not produce a heart murmur or gallop sound. Substantial left atrial enlargement can often be identified radiographically in cats with severe HCM. Biomarkers should not be relied on solely to diagnose the disease. While severe feline HCM can usually be diagnosed via echocardiography alone, feline HCM with mild to moderate left ventricular (LV) wall thickening is a diagnosis of exclusion, which means there is no definitive test for HCM in these cats and so other disorders that can cause mild to moderate LV wall thickening (eg, hyperthyroidism, systemic hypertension, acromegaly, dehydration) need to be ruled out. Key findings: While a genetic cause of HCM has been identified in two breeds and is suspected in another, for most cats the cause is unknown. Systolic anterior motion of the mitral valve (SAM) is the most common cause of dynamic left ventricular outflow tract obstruction (DLVOTO) and, in turn, the most common cause of a heart murmur with feline HCM. While severe DLVOTO is probably clinically significant and so should be treated, lesser degrees probably are not. Furthermore, since SAM can likely be induced in most cats with HCM, the distinction between HCM without obstruction and HCM with obstruction (HOCM) is of limited importance in cats. Diastolic dysfunction, and its consequences of abnormally increased atrial pressure leading to signs of heart failure, and sluggish atrial blood flow leading to ATE, is the primary abnormality that causes clinical signs and death in affected cats. Treatment (eg, loop diuretics) is aimed at controlling heart failure. Preventive treatment (eg, antithrombotic drugs) is aimed at reducing the risk of complications (eg, ATE). Conclusions: Most cats with HCM show no overt clinical signs and live a normal or near-normal life despite this disease. However, a substantial minority of cats develop overt clinical signs referable to heart failure or ATE that require treatment. For most cats with clinical signs caused by HCM, the long-term prognosis is poor to grave despite therapy. Areas of uncertainty: Genetic mutations (variants) that cause HCM have been identified in a few breeds, but, despite valiant efforts, the cause of HCM in the vast majority of cats remains unknown. No treatment currently exists that reverses or even slows the cardiomyopathic process in HCM, again despite valiant efforts. The search goes on.

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“…Moreover, echocardiographic evaluation of left atrial pump function can be complicated as LA size is strongly influenced by both ventricular function and loading conditions. For instance, there are reports of increased atrial function under pimobendan treatment, as assessed by LA fractional shortening in two recent feline studies ( 7 , 8 ), but no evidence of improvement in dogs with degenerative mitral valve disease (DMVD) ( 9 ). Therefore, we sought to further investigate the effects of pimobendan on the LA in canine DCM by focusing on multiple echocardiographic indicators of size and function.…”

Section: Introductionmentioning

confidence: 99%

Acute Effects of Pimobendan on Cardiac Function in Dogs With Tachycardia Induced Dilated Cardiomyopathy: A Randomized, Placebo-Controlled, Crossover Study

et al. 2021

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Background: Pimobendan provides a significant survival benefit in dogs with cardiac disease, including degenerative mitral valve disease and dilated cardiomyopathy (DCM). Its positive inotropic effect is well-known, however, it has complex effects and the mechanisms behind the survival benefit are not fully characterized. Secondary hemodynamic effects may decrease mitral regurgitation (MR) in DCM, and the benefits of pimobendan may extend to improved cardiac relaxation and improved atrial function.Hypothesis/Objectives: Our objective was to investigate the acute cardiac effects of pimobendan in dogs with a DCM phenotype. We hypothesized that pimobendan would increase left atrial (LA) contractility, reduce mitral regurgitation, improve diastolic function, and lower circulating NT-ProBNP levels.Animals: Seven purpose-bred Beagles were studied from a research colony with tachycardia induced DCM phenotype.Methods: The effects of pimobendan were studied under a placebo-controlled single-blinded cross-over design. In short, dogs underwent baseline and 3 h post-dose examinations 7 days apart with echocardiography and a blood draw. Dogs were randomized to receive oral placebo or 0.25 mg/kg pimobendan after their baseline exam. Investigators were blinded to treatments until all measurements were compiled.Results: When treated with pimobendan, the dogs had significant increases in systolic function and decreases in MR, compared to when treated with placebo.There were no detectable differences in left atrial measures, including LA size, LA emptying fraction, LA functional index or mitral A wave velocity. Heart rate decreased significantly with pimobendan compared to placebo. There was also a decrease in isovolumetric relaxation time normalized to heart rate. NT-proBNP levels had a high degree of variability.Conclusions: Improved mitral regurgitation severity and improved lusitropic function may contribute to the reported survival benefit for dogs with cardiac disease administered pimobendan. Pimobendan did not overtly improve LA function as assessed by echocardiography, and NT-proBNP was not significantly changed with a single dose of this medication. Further studies are needed to better characterize LA effects with other imaging modalities, to better quantify the total improvement of MR severity, and to assess chronic use of pimobendan on diastolic function in DCM.

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Effect of pimobendan on left atrial function: an echocardiographic pilot study in 11 healthy cats

Cited by 11 publications

References 35 publications

Effects of pimobendan on left atrial transport function in cats

Effects of pimobendan on left atrial transport function in cats

The Feline Cardiomyopathies: 2. Hypertrophic cardiomyopathy

Acute Effects of Pimobendan on Cardiac Function in Dogs With Tachycardia Induced Dilated Cardiomyopathy: A Randomized, Placebo-Controlled, Crossover Study

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