Effect of pimobendan on mitral annular dynamics and mitral regurgitation in dogs with myxomatous mitral valve disease as determined by cardiac computed tomography.

Pimobendan reduces mitral regurgitation severity by improving mitral annular contraction in stage B2 MMVD.

This prospective study evaluated pimobendan's effects on mitral annular dynamics (MAD) and mitral regurgitation (MR) severity in 20 dogs with ACVIM stage B2 myxomatous mitral valve disease (MMVD). Dogs underwent echocardiographic and cardiac computed tomographic (CCT) imaging before and 2 weeks after pimobendan administration. Pimobendan significantly decreased normalized end-systolic mitral annular area, aortoparietal distance, and intercommissural distance while increasing leaflet-to-annulus index. Notably, pimobendan reduced regurgitant volume by 0.31 mL/kg and regurgitant fraction by 9.8%. Left ventricular and atrial volumes also decreased significantly. No adverse events occurred during the study period. Aortic distensibility remained unchanged. These findings demonstrate that pimobendan reduces MR severity in early-stage MMVD through enhanced systolic contraction of the mitral annulus, providing mechanistic insight into its therapeutic benefits. The study suggests pimobendan may slow MMVD progression in stage B2 disease, though longer-term studies are needed to confirm clinical efficacy.

This summary was distilled by AI and may occasionally misinterpret data. Confirm critical details with the primary literature before clinical application.