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Ejection Fraction
An ejection fraction (EF) is the volumetric fraction (or portion of the total) of fluid (usually blood) ejected from a chamber (usually the heart) with each contraction (or heartbeat). It can refer to the cardiac atrium, cardiac ventricle, gall bladder, or leg veins, although if unspecified it usually refers to the left ventricle of the heart. EF is widely used as a measure of the pumping efficiency of the heart and is used to classify heart failure types. It is also used as an indicator of the severity of heart failure, although it has recognized limitations. The EF of the left heart, known as the left ventricular ejection fraction (LVEF), is calculated by dividing the volume of blood pumped from the left ventricle per beat ( stroke volume) by the volume of blood present in the left ventricle at the end of diastolic filling ( end-diastolic volume). LVEF is an indicator of the effectiveness of pumping into the systemic circulation. The EF of the right heart, or right ventricul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraction (mathematics)
A fraction (from , "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight-fifths, three-quarters. A ''common'', ''vulgar'', or ''simple'' fraction (examples: and ) consists of an integer numerator, displayed above a line (or before a slash like ), and a division by zero, non-zero integer denominator, displayed below (or after) that line. If these integers are positive, then the numerator represents a number of equal parts, and the denominator indicates how many of those parts make up a unit or a whole. For example, in the fraction , the numerator 3 indicates that the fraction represents 3 equal parts, and the denominator 4 indicates that 4 parts make up a whole. The picture to the right illustrates of a cake. Fractions can be used to represent ratios and division (mathematics), division. Thus the fraction can be used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Medicine
Nuclear medicine (nuclear radiology, nucleology), is a medical specialty involving the application of radioactivity, radioactive substances in the diagnosis and treatment of disease. Nuclear imaging is, in a sense, ''radiology done inside out'', because it records radiation radiant exitance, emitted from within the body rather than radiation that is transmittance, transmitted through the body from external sources like X-ray generators. In addition, nuclear medicine scans differ from radiology, as the emphasis is not on imaging anatomy, but on the function. For such reason, it is called a Functional imaging, physiological imaging modality. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) scans are the two most common imaging modalities in nuclear medicine. Diagnostic medical imaging Diagnostic In nuclear medicine imaging, radiopharmaceuticals are taken internally, for example, through inhalation, intravenously, or orally. Then, externa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Motu Cordis
''Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus'' (Latin, 'An Anatomical Exercise on the Motion of the Heart and Blood in Living Beings'), commonly called ''De Motu Cordis'', is the best-known work of the physician William Harvey, which was first published in 1628 and established the circulation of blood throughout the body. It is a landmark in the history of physiology, with Harvey combining observations, experiments, measurements, and hypotheses in an extraordinary fashion to arrive at his doctrine. His work is a model of its kind and had an immediate and far-reaching influence on Harvey's contemporaries; Thomas Hobbes said that Harvey was the only modern author whose doctrines were taught in his lifetime. In ''De motu cordis'', Harvey investigated the effect of ligatures on blood flow. The book also argued that blood was pumped around the body in a "double circulation", where after being returned to the heart, it is recirculated in a closed system to the lu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Harvey
William Harvey (1 April 1578 – 3 June 1657) was an English physician who made influential contributions to anatomy and physiology. He was the first known physician to describe completely, and in detail, pulmonary and systemic circulation as well as the specific process of blood being pumped to the brain and the rest of the body by the heart (though earlier writers, such as Realdo Colombo, Michael Servetus, and Jacques Dubois, had provided precursors to some of his theories). Family William's father, Thomas Harvey, was a jurat of Folkestone where he served as mayor in 1600. Records and personal descriptions delineate him as an overall calm, diligent, and intelligent man whose sons “... revered, consulted and implicitly trusted in him...” (they) made their father the treasurer of their wealth when they acquired great estates...(He) kept, employed, and improved their gainings to their great advantage." Thomas Harvey's portrait can still be seen in the central panel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percentage
In mathematics, a percentage () is a number or ratio expressed as a fraction (mathematics), fraction of 100. It is often Denotation, denoted using the ''percent sign'' (%), although the abbreviations ''pct.'', ''pct'', and sometimes ''pc'' are also used. A percentage is a dimensionless quantity, dimensionless number (pure number), primarily used for expressing proportions, but percent is nonetheless a unit of measurement in its orthography and usage. Examples For example, 45% (read as "forty-five percent") is equal to the fraction , or 0.45. Percentages are often used to express a proportionate part of a total. (Similarly, one can also express a number as a fraction of 1,000, using the term "per mille" or the symbol "".) Example 1 If 50% of the total number of students in the class are male, that means that 50 out of every 100 students are male. If there are 500 students, then 250 of them are male. Example 2 An increase of $0.15 on a price of $2.50 is an increase by a fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ratio
In mathematics, a ratio () shows how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ratio 4:3). Similarly, the ratio of lemons to oranges is 6:8 (or 3:4) and the ratio of oranges to the total amount of fruit is 8:14 (or 4:7). The numbers in a ratio may be quantities of any kind, such as counts of people or objects, or such as measurements of lengths, weights, time, etc. In most contexts, both numbers are restricted to be Positive integer, positive. A ratio may be specified either by giving both constituting numbers, written as "''a'' to ''b''" or "''a'':''b''", or by giving just the value of their quotient Equal quotients correspond to equal ratios. A statement expressing the equality of two ratios is called a ''proportion''. Consequently, a ratio may be considered as an ordered pair of numbers, a Fraction (mathematic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
End-systolic Volume
End-systolic volume (ESV) is the volume of blood in a ventricle at the end of contraction, or systole, and the beginning of filling, or diastole. ESV is the lowest volume of blood in the ventricle at any point in the cardiac cycle. The main factors that affect the end-systolic volume are afterload and the contractility of the heart. __TOC__ Uses End systolic volume can be used clinically as a measurement of the adequacy of cardiac emptying, related to systolic function. On an electrocardiogram, or ECG, the end-systolic volume will be seen at the end of the T wave. Clinically, ESV can be measured using two-dimensional echocardiography, MRI (magnetic resonance tomography) or cardiac CT (computed tomography) or SPECT (single photon emission computed tomography). Sample values Along with end-diastolic volume, ESV determines the stroke volume, or output of blood by the heart during a single phase of the cardiac cycle. The stroke volume In cardiovascular physiology, stroke volume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Social Security Administration
The United States Social Security Administration (SSA) is an Independent agencies of the United States government, independent agency of the Federal government of the United States, U.S. federal government that administers Social Security (United States), Social Security, a social insurance program consisting of retirement, disability and survivor benefits. The Social Security Administration was established by the Social Security Act of 1935 and is codified in (). It was created in 1935 as the "Social Security Board", then assumed its present name in 1946. Its current leader is Commissioner Frank Bisignano. SSA offers its services to the public through 1,200 field offices, a website, and a national toll-free number. Field offices, which served 43 million individuals in 2019, were reopened on April 7, 2022 after being closed for two years due to the COVID-19 pandemic. SSA is headquartered in Woodlawn, Baltimore County, Maryland, Woodlawn, Maryland, just to the west of Baltimore, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Society Of Cardiology
The European Society of Cardiology (ESC) is an independent Nonprofit organisation, non-profit, non-governmental professional association that works to advance the prevention, diagnosis and management of diseases of the heart and blood vessels, and improve scientific understanding of the heart and vascular system. This is done by: * Disseminating evidence-based, scientific knowledge through courses, webinars, scientific journals, books and an annual cardiovascular congress. * Harmonising standards of care through the publication of ESC Clinical Practice Guidelines. * Shaping heart-health policy and regulation by fostering partnerships and providing scientific expertise and independent data. Most of the approximately 100,000 ESC members are cardiologists, cardiovascular nurses and allied professionals wishing to increase their knowledge and update their skills. The association adheres to the Alliance for Biomedical Research in Europe Code of Conduct. History The ESC was founded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiomyopathy
Cardiomyopathy is a group of primary diseases of the heart muscle. Early on there may be few or no symptoms. As the disease worsens, shortness of breath, feeling tired, and swelling of the legs may occur, due to the onset of heart failure. An irregular heart beat and fainting may occur. Those affected are at an increased risk of sudden cardiac death. As of 2013, cardiomyopathies are defined as "disorders characterized by morphologically and functionally abnormal myocardium in the absence of any other disease that is sufficient, by itself, to cause the observed phenotype." Types of cardiomyopathy include hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular dysplasia, and Takotsubo cardiomyopathy (broken heart syndrome). In hypertrophic cardiomyopathy the heart muscle enlarges and thickens. In dilated cardiomyopathy the ventricles enlarge and weaken. In restrictive cardiomyopathy the ventricle stiffens. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myocardial Infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom is retrosternal Angina, chest pain or discomfort that classically radiates to the left shoulder, arm, or jaw. The pain may occasionally feel like heartburn. This is the dangerous type of acute coronary syndrome. Other symptoms may include shortness of breath, nausea, presyncope, feeling faint, a diaphoresis, cold sweat, Fatigue, feeling tired, and decreased level of consciousness. About 30% of people have atypical symptoms. Women more often present without chest pain and instead have neck pain, arm pain or feel tired. Among those over 75 years old, about 5% have had an MI with little or no history of symptoms. An MI may cause heart failure, an Cardiac arrhythmia, irregular heartbeat, cardiogenic shock or cardiac arrest. Most MIs occur d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myocardium
Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall (the pericardium) and the inner layer (the endocardium), with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix. Cardiac muscle contracts in a similar manner to skeletal muscle, although with some important differences. Electrical stimulation in the form of a cardiac action potential triggers the release of calcium from the cell's internal calcium store, the sarcoplasmic reticulum. The rise in calcium causes the cell's myofilaments to slide past each other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
