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Inotropic
An inotrope 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. However, it can also refer to pathological conditions. For example, enlarged heart muscle can increase inotropic state, whereas dead heart muscle can decrease it. 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 al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dopexamine
Dopexamine is a synthetic analogue of dopamine that is administered intravenously in hospitals to reduce exacerbations of heart failure and to treat heart failure following cardiac surgery. It is not used often, as more established drugs like epinephrine, dopamine, dobutamine, norepinephrine, and levosimendan work as well. It works by stimulating beta-2 adrenergic receptors and peripheral dopamine receptor D1 and dopamine receptor D2. It also inhibits the neuronal re-uptake of norepinephrine. The most common adverse effects include fast heart beats and nausea. It was discovered by scientists at Fisons, which licensed it to Ipsen in 1993, and Ipsen in turn licensed it to Élan in 1999. Ipsen licensed rights in North America and Japan to Circassia in 2008; the drug had never been approved in those countries. Dopexamine went off-patent in 2010. Medical use Dopexamine is used in hospitals as an inotropic agent to reduce exacerbations of heart failure and to trea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myocardial Contractility
Myocardial contractility represents the innate ability of the heart muscle (cardiac muscle or myocardium) to contract. The ability to produce changes in force during contraction result from incremental degrees of binding between different types of tissue, that is, between filaments of myosin (thick) and actin (thin) tissue. The degree of binding depends upon the concentration of calcium ions in the cell. Within an in vivo intact heart, the action/response of the sympathetic nervous system is driven by precisely timed releases of a catecholamine, which is a process that determines the concentration of calcium ions in the cytosol of cardiac muscle cells. The factors causing an increase in contractility work by causing an increase in intracellular calcium ions (Ca++) during contraction. Mechanisms for altering contractility Increasing contractility is done primarily through increasing the influx of calcium or maintaining higher calcium levels in the cytosol of cardiac myocytes during a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levosimendan
Levosimendan (INN) is a calcium sensitizer used in the management of acutely decompensated congestive heart failure. It is marketed under the trade name Simdax ( Orion Corporation). Overall the drug has a two fold mechanism of action. It leads to greater ionotrophy by increasing the calcium sensitivity as it binds to Troponin and this results in a greater positive iontrophic force. Secondly, the drug is able to open ATP sensitive potassium channels in vascular smooth muscle cells, and the vascular dilatory effects of the drug lead to a decreased pre-load and afterload, putting less work on the heart. This drug is in the process of review by the FDA but has not been approved yet. Mechanism of action Levosimendan is a calcium sensitizer — it increases the sensitivity of the heart to calcium, thus increasing cardiac contractility without a rise in intracellular calcium. Levosimendan exerts its positive inotropic effect by increasing calcium sensitivity of myocytes by binding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dobutamine
Dobutamine is a medication used in the treatment of cardiogenic shock (as a result of inadequate tissue perfusion) and severe heart failure. It may also be used in certain types of cardiac stress tests. It is given by IV only, as an injection into a vein or intraosseous as a continuous infusion. The amount of medication needs to be adjusted to the desired effect. Onset of effects is generally seen within 2 minutes. It has a half-life of two minutes. This drug is generally only administered short term, although it may be used for longer periods to relieve symptoms of heart failure in patients awaiting heart transplantation. Common side effects include a fast heart rate, an irregular heart beat, and inflammation at the site of injection. Use is not recommended in those with idiopathic hypertrophic subaortic stenosis. It primarily works by direct stimulation of β1 receptors, which increases the strength of the heart's contractions, leading to a positive ionotrophic effect. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiogenic Shock
Cardiogenic shock (CS) is a medical emergency resulting from inadequate blood flow due to the dysfunction of the ventricles of the heart.Textbooks of Internal MedicinHarrison's Principles of Internal Medicine 16th Edition, The McGraw-Hill CompaniesCecil Textbook of Medicine by Lee Goldman, Dennis Ausiello, 22nd Edition (2003), W. B. Saunders CompanyThe Oxford Textbook of Medicine Edited by David A. Warrell, Timothy M. Cox and John D. Firth with Edward J. Benz, Fourth Edition (2003), Oxford University Press, Shock: An Overview PDF by Michael L. Cheatham, MD, Ernest F.J. Block, MD, Howard G. Smith, MD, John T. Promes, MD, Surgical Critical Care Service, Department of Surgical Education, |
Decompensation
In medicine, decompensation is the functional deterioration of a structure or system that had been previously working with the help of compensation. Decompensation may occur due to fatigue, stress, illness, or old age. When a system is "compensated," it is able to function despite stressors or defects. Decompensation describes an inability to compensate for these deficiencies. It is a general term commonly used in medicine to describe a variety of situations. Physiology For example, ''cardiac decompensation'' may refer to the failure of the heart to maintain adequate blood circulation, after long-standing (previously compensated) vascular disease (see heart failure). Short-term treatment of cardiac decompensation can be achieved through administration of dobutamine, resulting in an increase in heart contractility via an inotropic effect. Kidney failure can also occur following a slow degradation of kidney function due to an underlying untreated illness; the symptoms of the la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasopressors
An antihypotensive agent, also known as a vasopressor agent or simply vasopressor, or pressor, is any substance, whether endogenous or a medication, that tends to raise low blood pressure. Some antihypotensive drugs act as vasoconstrictors to increase total peripheral resistance, others sensitize adrenoreceptors to catecholamines - glucocorticoids, and the third class increase cardiac output - dopamine, dobutamine. If low blood pressure is due to blood loss, then preparations increasing volume of blood circulation—plasma-substituting solutions such as colloid and crystalloid solutions (salt solutions)—will raise the blood pressure without any direct vasopressor activity. Packed red blood cells, plasma or whole blood should not be used solely for volume expansion or to increase oncotic pressure of circulating blood. Blood products should only be used if reduced oxygen carrying capacity or coagulopathy is present. Other causes of either absolute (dehydration, loss of plasm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congestive Heart Failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, and leg swelling. The shortness of breath may occur with exertion or while lying down, and may wake people up during the night. Chest pain, including angina, is not usually caused by heart failure, but may occur if the heart failure was caused by a heart attack. The severity of the heart failure is measured by the severity of symptoms during exercise. Other conditions that may have symptoms similar to heart failure include obesity, kidney failure, liver disease, anemia, and thyroid disease. Common causes of heart failure include coronary artery disease, heart attack, high blood pressure, atrial fibrillation, valvular heart disease, excessive alcohol consumption, infection, and cardiomyopathy. These cause heart failure by alterin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Scientific Vocabulary
International scientific vocabulary (ISV) comprises scientific and specialized words whose language of origin may or may not be certain, but which are in current use in several modern languages (that is, translingually, whether in naturalized, loanword, or calque forms). The name "international scientific vocabulary" was first used by Philip Gove in '' Webster's Third New International Dictionary'' (1961). As noted by David Crystal, science is an especially productive field for new coinages. It is also especially predisposed to immediate translingual sharing of words owing to its very nature: scientists working in many countries and languages, reading each other's latest articles in scientific journals (via foreign language skills, translation help, or both), and eager to apply any reported advances to their own context. Instances According to ''Webster's Third'', "some ISV words (like haploid) have been created by taking a word with a rather general and simple meaning from o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dopamine
Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 80% of the catecholamine content in the brain. It is an amine synthesized by removing a carboxyl group from a molecule of its precursor chemical, L-DOPA, which is synthesized in the brain and kidneys. Dopamine is also synthesized in plants and most animals. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons (nerve cells) to send signals to other nerve cells. Neurotransmitters are synthesized in specific regions of the brain, but affect many regions systemically. The brain includes several distinct dopamine pathways, one of which plays a major role in the motivational component of reward-motivated behavior. The anticipation of most types of rewards increases the level of dopamine in the brain, and many ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catecholamine
A catecholamine (; abbreviated CA) is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine. Catechol can be either a free molecule or a substituent of a larger molecule, where it represents a 1,2-dihydroxybenzene group. Catecholamines are derived from the amino acid tyrosine, which is derived from dietary sources as well as synthesis from phenylalanine. Catecholamines are water-soluble and are 50% bound to plasma proteins in circulation. Included among catecholamines are epinephrine (adrenaline), norepinephrine (noradrenaline), and dopamine. Release of the hormones epinephrine and norepinephrine from the adrenal medulla of the adrenal glands is part of the fight-or-flight response. Tyrosine is created from phenylalanine by hydroxylation by the enzyme phenylalanine hydroxylase. Tyrosine is also ingested directly from dietary protein. Catecholamine-secreting cells u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust, and the third most abundant metal, after iron and aluminium. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilised remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin ''calx'' " lime", which was obtained from heating limestone. Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in food ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
