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Effects of pimobendan on left atrial transport function in cats
Samantha L Kochie1, Karsten E Schober1, Jaylyn Rhinehart1
1Department of Veterinary Clinical Sciences, The Ohio State University, Columbus, Ohio, USA.
Insights
Pimobendan showed minor positive effects on left atrial (LA) function in cats with hypertrophic cardiomyopathy (HCM). Further research is needed to determine if this drug reduces the risk of blood clots in these cats.
Area of Science:
- Cardiology
- Veterinary Medicine
- Pharmacology
Background:
- Arterial thromboembolism is a significant complication in cats with hypertrophic cardiomyopathy (HCM).
- Left atrial (LA) enlargement and dysfunction are key factors contributing to thromboembolism in HCM cats.
Purpose of the Study:
- To evaluate the effect of pimobendan on left atrial (LA) size and function in cats with HCM.
- To compare the effects of pimobendan in cats with HCM versus healthy cats.
Main Methods:
- A prospective, double-blind, randomized, placebo-controlled study was conducted.
- Twenty-two cats with HCM and 11 healthy cats received either pimobendan or a placebo for 4-7 days.
- Nineteen echocardiographic variables assessing LA size and function were analyzed.
Main Results:
- Pimobendan treatment increased several measures of LA function, including peak velocity of left auricular appendage flow and late diastolic transmitral flow.
- The drug demonstrated a more pronounced positive effect on LA function in cats with HCM compared to healthy controls.
- These beneficial effects were observed independently of LA size.
Conclusions:
- Pimobendan has a positive, though minor, impact on left atrial (LA) function in cats suffering from hypertrophic cardiomyopathy (HCM).
- Further investigation is warranted to ascertain if pimobendan can mitigate the risk of cardiogenic embolism in feline HCM patients.
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.
