Congestive heart failure positive inotropics
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
- Agents that increase intracellular cAMP
- Alpha-adrenergic agonists
- Phosphodiesterase inhibitors
- Agents that affect sarcolemmal ion pumps/channels
- Agents that modulate intracellular calcium mechanisms by either:
- Release of sarcoplasmic reticulum calcium (IP3)
- Increased sensitization of the contractile proteins to calcium
- Drugs having multiple mechanisms of action
- Pimobendan
- Vesnarinone
Digoxin
- Inhibits Na,K+-ATPase resulting in an increase in intracellular Na+, extracellular Ca2+ exchange increasing the velocity and extent of sarcomere shortening.
- ACC/AHA recommend digoxin for symptomatic patients with left ventricular systolic dysfunction.
- Commonly used in patients with heart failure and atrial fibrillation to reduce the ventricular response rate.
- Mortality has not been shown to be improved with use of digoxin[1], but the use of digoxin has been associated with a reduction in hospitalization in the RALES study.
- There is no need to load a CHF patient with digoxin. For the majority of patients with normal renal function, a daily dose of 0.25 mg of digoxin is usually adequate. In the older patient or in those patients with renal impairment, a dose of 0.125 mg per day may be adequate.
- Drugs that increase the concentration of digoxin include antibiotics and anticholinergic agents as well as amiodarone, quinidine and verapamil.
- In the RALES study, a level of < 1 ng/ml was associated with efficacy. Levels above 1 ng/ml were not associated with greater efficacy and were associated with higher mortality.
ACC/AHA Guidelines- Digitalis (DO NOT EDIT) [2][3]
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Class IIa1. Digitalis can be beneficial in patients with current or prior symptoms of heart failure and reduced left ventricular ejection fraction (LVEF) to decrease hospitalizations for heart failure. (Level of Evidence: B) |
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Dobutamine
- Activates beta-1 receptors resulting in enhanced cardiac contractility.
- Long-term dobutamine infusions are arrhythmogenic and increase mortality.
- Dobutamine also slightly reduces afterload
Dopamine
- Unique dose dependent mechanism of action.
- At low doses: (≤2 µg/kg/min), selective dilation of splanchnic and renal arterial beds. assists in increasing renal perfusion.
- At intermediate doses: (2 to 10 µg/kg/min), increased norepinephrine secretion results in increased cardiac contractility, heart rate and systemic vascular resistance.
- At higher doses: (5 to 20 µg/kg/min), direct alpha-adrenergic receptor stimulation increases systemic vascular resistance.
Milrinone
- Phosphodiesterase-III inhibitor that enhances cardiac contractility by increasing intracellular cyclic adenosine monophosphate (cAMP).
- Potent pulmonary vasodilator that may benefit some patients with pulmonary hypertension.
- Unlike dobutamine milrinone is beneficial in decompensated heart failure patients who are on beta-blocker therapy.
- Long term milrinone infusions are arrhythmogenic, and increase mortality.
References
- ↑ "The effect of digoxin on mortality and morbidity in patients with heart failure. The Digitalis Investigation Group". The New England Journal of Medicine. 336 (8): 525–33. 1997. doi:10.1056/NEJM199702203360801. PMID 9036306. Retrieved 2012-04-05. Unknown parameter
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ignored (help) - ↑ Hunt SA, Abraham WT, Chin MH, Feldman AM, Francis GS, Ganiats TG, Jessup M, Konstam MA, Mancini DM, Michl K, Oates JA, Rahko PS, Silver MA, Stevenson LW, Yancy CW, Antman EM, Smith SC Jr, Adams CD, Anderson JL, Faxon DP, Fuster V, Halperin JL, Hiratzka LF, Jacobs AK, Nishimura R, Ornato JP, Page RL, Riegel B; American College of Cardiology; American Heart Association Task Force on Practice Guidelines; American College of Chest Physicians; International Society for Heart and Lung Transplantation; Heart Rhythm Society. ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the Adult: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Update the 2001 Guidelines for the Evaluation and Management of Heart Failure): developed in collaboration with the American College of Chest Physicians and the International Society for Heart and Lung Transplantation: endorsed by the Heart Rhythm Society. Circulation. 2005 Sep 20; 112(12): e154-235. Epub 2005 Sep 13. PMID 16160202
- ↑ Jessup M, Abraham WT, Casey DE, Feldman AM, Francis GS, Ganiats TG et al. (2009) 2009 focused update: ACCF/AHA Guidelines for the Diagnosis and Management of Heart Failure in Adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines: developed in collaboration with the International Society for Heart and Lung Transplantation. Circulation 119 (14):1977-2016. DOI:10.1161/CIRCULATIONAHA.109.192064 PMID: 19324967