Not to be confused with ionotropic.
An inotrope[help 1] is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction.
The term inotropic state is most commonly used in reference to various drugs that affect the strength of contraction of heart muscle (myocardial contractility). However, it can also refer to pathological conditions. For example, enlarged heart muscle (ventricular hypertrophy) can increase inotropic state, whereas dead heart muscle (myocardial infarction) can decrease it.
Contents
- 1 Medical uses
- 2 Positive inotropic agents
- 3 Negative inotropic agents
- 4 See also
- 5 Notes
- 6 References
Medical uses
Both positive and negative inotropes are used in the management of various cardiovascular conditions. The choice of agent depends largely on specific pharmacological effects of individual agents with respect to the condition. One of the most important factors affecting inotropic state is the level of calcium in the cytoplasm of the muscle cell. Positive inotropes usually increase this level, while negative inotropes decrease it. However, not all positive and negative drugs affect calcium release, and, among those that do, the mechanism for manipulating the calcium level can differ from drug to drug.
While it is often recommended that vasopressors are given through a central line due to the risk of local tissue injury if the medication enters the local tissue, they are likely safe when given for less than two hours in a good peripheral iv.[6]
Positive inotropic agents
Positive inotropic agents increase myocardial contractility, and are used to support cardiac function in conditions such as decompensated congestive heart failure, cardiogenic shock, septic shock, myocardial infarction, cardiomyopathy, etc.
Examples of positive inotropic agents include:
- Digoxin
- Amiodarone
- Berberine
- Calcium
- Calcium sensitisers
- Cardiac myosin activators
- Catecholamines
- Dopamine
- Dobutamine
- Dopexamine
- Epinephrine (adrenaline)
- Isoprenaline (isoproterenol)
- Norepinephrine (noradrenaline)
- Angiotensin II
- Eicosanoids
- Phosphodiesterase inhibitors
- Enoximone
- Milrinone
- Amrinone
- Theophylline
- Glucagon
- Insulin
Negative inotropic agents
Negative inotropic agents decrease myocardial contractility, and are used to decrease cardiac workload in conditions such as angina. While negative inotropism may precipitate or exacerbate heart failure, certain beta blockers (e.g. carvedilol, bisoprolol and metoprolol) have been believed to reduce morbidity and mortality in congestive heart failure. Quite recently, however, the effectiveness of beta blockers has come under renewed critical scientific scrutiny.[citation needed]
Examples of negative inotropic agents include:
- Beta blockers
- Calcium channel blockers
- Diltiazem
- Verapamil
- Clevidipine
Class IA antiarrhythmics such as
- Quinidine
- Procainamide
- disopyramide
Class IC antiarrhythmics such as
See also
- Pressors
- Bathmotropic
- Dromotropic
Notes
- ^ The word inotrope is ISV via New Latin, from Greek in-, fibre or sinew, plus -trope, turning or moving. The prevalent pronunciations are [1][2] and ,[3][4] with [2][5] being less common.
References
- ^ Merriam-Webster, Merriam-Webster's Collegiate Dictionary, Merriam-Webster.
- ^ a b Houghton Mifflin Harcourt, The American Heritage Dictionary of the English Language, Houghton Mifflin Harcourt.
- ^ Elsevier, Dorland's Illustrated Medical Dictionary, Elsevier.
- ^ Wolters Kluwer, Stedman's Medical Dictionary, Wolters Kluwer.
- ^ Merriam-Webster, Merriam-Webster's Medical Dictionary, Merriam-Webster.
- ^ Loubani, OM; Green, RS (June 2015). "A systematic review of extravasation and local tissue injury from administration of vasopressors through peripheral intravenous catheters and central venous catheters.". Journal of critical care. 30 (3): 653.e9–17. doi:10.1016/j.jcrc.2015.01.014. PMID 25669592.
- ^ Schrör K, Hohlfeld T (1992). "Inotropic actions of eicosanoids". Basic Res. Cardiol. 87 (1): 2–11. doi:10.1007/BF00795384. PMID 1314558.
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Physiology of the cardiovascular system
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| Heart |
| Cardiac output |
- Cardiac cycle
- Cardiac output
- Stroke volume
- End-diastolic volume
- End-systolic volume
- Afterload
- Preload
- Frank–Starling law of the heart
- Cardiac function curve
- Venous return curve
- Wiggers diagram
- Pressure volume diagram
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| Ultrasound |
- Fractional shortening = (End-diastolic dimension
- End-systolic dimension) / End-diastolic dimension
- Aortic valve area calculation
- Ejection fraction
- Cardiac index
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| Heart rate |
- Cardiac pacemaker
- Chronotropic (Heart rate)
- Dromotropic (Conduction velocity)
- Inotropic (Contractility)
- Bathmotropic (Excitability)
- Lusitropic (Relaxation)
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| Conduction |
- Conduction system
- Cardiac electrophysiology
- Action potential
- cardiac
- atrial
- ventricular
- Effective refractory period
- Pacemaker potential
- Electrocardiography
- P wave
- PR interval
- QRS complex
- QT interval
- ST segment
- T wave
- U wave
- Hexaxial reference system
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| Chamber pressure |
- Central venous
- Right
- pulmonary artery
- Left
- Aortic
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| Other |
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Vascular system/
Hemodynamics |
| Blood flow |
- Compliance
- Vascular resistance
- Pulse
- Perfusion
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| Blood pressure |
- Pulse pressure
- Mean arterial pressure
- Jugular venous pressure
- Portal venous pressure
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| Regulation of BP |
- Baroreflex
- Kinin–kallikrein system
- Renin–angiotensin system
- Vasoconstrictors
- Vasodilators
- Autoregulation
- Myogenic mechanism
- Tubuloglomerular feedback
- Cerebral autoregulation
- Paraganglia
- Aortic body
- Carotid body
- Glomus cell
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