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A novel approach to the development of positive inotropic agents for chronic heart failure
1Division of Circulatory Physiology and Center for Heart Failure Research, Columbia University, College of Physicians and Surgeons, New York, USA.
Insights
Positive inotropic agents for chronic congestive heart failure (CHF) may benefit patients through non-contractile effects, not direct heart stimulation. Optimal dosing might involve minimal to no positive inotropic action.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Positive inotropic agents show favorable hemodynamic effects but lack long-term clinical benefits in chronic congestive heart failure (CHF).
- This has led to suggestions to abandon inotropic therapy for CHF.
Purpose of the Study:
- To explore the discrepancy between the lack of long-term benefits and potential clinical improvements with positive inotropic agents in CHF.
- To investigate the role of non-inotropic actions of these drugs at low doses.
Main Methods:
- Review of existing literature on positive inotropic agents in CHF.
- Analysis of hemodynamic effects versus clinical outcomes at varying drug doses.
Main Results:
- Clinical benefits may occur at doses with negligible effects on cardiac contractility.
- Ancillary circulatory actions of positive inotropic agents at low doses may be responsible for therapeutic benefits.
- High doses, with significant positive inotropic effects, might be linked to adverse outcomes.
Conclusions:
- Hemodynamic activity should not solely guide positive inotropic agent dosing in CHF.
- The ideal dose may exert minimal to no positive inotropic effect.
- Non-inotropic properties are crucial for therapeutic efficacy in CHF management.
Abstract:
Although positive inotropic agents exert favorable hemodynamic effects, long-term therapy with these drugs has not produced clinical benefits and has increased the mortality of patients with chronic congestive heart failure (CHF). This experience has led many physicians to suggest that positive inotropic therapy be abandoned as a therapeutic approach for this condition. However, positive inotropic drugs can produce clinical benefits in many patients but, ironically, this improvement may be principally seen at doses that produce negligible effects on cardiac contractility. This apparent discrepancy may be explained by the fact that many positive inotropic agents exert actions on the circulation in addition to stimulating the heart, and these ancillary properties may be particularly important with the use of low doses of these drugs. If the noninotropic actions of low doses are responsible for the therapeutic benefits of these drugs, the positive inotropic effects seen at high doses may be primarily responsible for their adverse (rather than their favorable) effects. Therefore, hemodynamic activity should not be viewed as a prerequisite for the selection of the dose of a drug for CHF. The ideal dose of a positive inotropic agent may be one that exerts no positive inotropic effect at all.