What question did this study set out to answer?

This study aims to compare the inotropic effects of pimobendan and milrinone on cardiac muscle preparations.

November 1, 1988Circulation ResearchOpen Access

Sensitization of dog and guinea pig heart myofilaments to Ca2+ activation and the inotropic effect of pimobendan: comparison with milrinone.

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Population

Intact and detergent-skinned preparations of cardiac muscle from dogs and guinea pigs

Comparison

Pimobendan (up to 50 microM) vs Milrinone (50 microM)

Design

Preclinical

Authors

KFKazuya FujinoFukuoka University NSN. SperelakisUniversity of Maryland, Baltimore RSR. John SolaroGeneral Cardiology

Discussion

Member takes

Implication

Pimobendan may sensitize myofilaments to Ca2+ unlike milrinone; leaves open translation to intact human myocardium or HF outcomes.

Key Points

This study aims to compare the inotropic effects of pimobendan and milrinone on cardiac muscle preparations.
Evaluated the effects of 50 µM pimobendan and milrinone on contractile force and calcium sensitivity in guinea pig and dog heart muscle preparations.
Used detergent-skinned and intact muscle preparations to measure changes in electrical, mechanical, and biochemical activities.
Assessments included measuring ATPase activity and force development across varying calcium concentrations.
Pimobendan significantly increased contractile force in guinea pig papillary muscles while milrinone did not enhance force further.
At pCa 6.25, pimobendan had a half-maximal concentration of approximately 40 µM for stimulating force development, while milrinone had no additional effect.
Pimobendan shifted force-pCa and ATPase-pCa relations to the left by 0.15-0.20 pCa units, indicating enhanced calcium sensitivity.

Structured PICO

Population

Intact and detergent-skinned preparations of cardiac muscle (papillary muscle and chemically-skinned muscle fibers) from dogs and guinea pigs

Intervention

Pimobendan (up to 50 microM)

Comparator

Milrinone (50 microM)

Outcome

Electrical, mechanical and biochemical activity (contractile force, slow action potentials, active tension, Mg-ATPase activity, and Ca2+ binding to troponin C)surrogate

Pimobendan's positive inotropic action involves direct sensitization of cardiac myofilaments to calcium via increased affinity of troponin C, a mechanism not shared by milrinone.

Cite This Study

Fujino et al. (1988) studied this question.

synapsesocial.com/papers/6a70c8a5fe4101aa97e04f21 https://doi.org/10.1161/01.res.63.5.911

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Sensitization of dog and guinea pig heart myofilaments to Ca2+ activation and the inotropic effect of pimobendan: comparison with milrinone.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Sensitization of dog and guinea pig heart myofilaments to Ca2+ activation and the inotropic effect of pimobendan: comparison with milrinone.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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