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Echocardiogram, often referred to as a cardiac echo or simply an echo, is a sonogram of the heart. (It is not abbreviated as ECG is an abbreviation for an electrocardiogram.) Echocardiography uses standard two-dimensional, three-dimensional, and Doppler ultrasound to create images of the heart. Echocardiography has become routinely used in the diagnosis, management, and follow-up of patients with any suspected or known heart diseases. It is one of the most widely used diagnostic tests in cardiology. It can provide a wealth of helpful information, including the size and shape of the heart (internal chamber size quantification), pumping capacity, and the location and extent of any tissue damage. An echocardiogram can also give physicians other estimates of heart function such as a calculation of the cardiac output, ejection fraction, and diastolic function (how well the heart relaxes). Echocardiography can help detect cardiomyopathies, such as hypertrophic cardiomyopathy, dilated cardiomyopathy, and many others. The use of Stress Echocardiography may also help determine whether any chest pain or associated symptoms are related to heart disease. The biggest advantage to echocardiography is that it is noninvasive (doesn't involve breaking the skin or entering body cavities) and has no known risks or side effects. Not only can an echocardiogram create ultrasound images of heart structures, but it can also produce accurate assessment of the blood flowing through the heart by Doppler echocardiography, using pulsed or continuous wave Doppler ultrasound. This allows assessment of both normal and abnormal blood flow through the heart. Color Doppler as well as spectral Doppler is used to visualize any abnormal communications between the left and right side of the heart, any leaking of blood through the valves (valvular regurgitation), and to estimate how well the valves open (or do not open in the case of valvular stenosis). The Doppler technique can also be used for tissue motion and velocity measurement, by Tissue Doppler echocardiography. Echocardiography was also the first ultrasound subspecialty to use intravenous contrast. (See Contrast Echocardiography) Echocardiography is performed by cardiac sonographers, cardiac physiologists (UK) or doctors trained in echocardiography. ==Indications== Health societies recommend the use of echocardiography for initial diagnosis when there is a change in the patient's clinical status and when new data from an echocardiogram would result in the physician changing the patient's care. Health societies do not recommend routine testing when the patient has no change in clinical status or when a physician is unlikely to change care for the patient based on the results of testing.〔 A common example of overuse of echocardiography when not indicated is the use of routine testing in response to a patient diagnosis of mild valvular heart disease. In this case, patients are often asymptomatic for years before the onset of deterioration and the results of the echocardiogram would not result in a change in care without other change in clinical status.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「echocardiography」の詳細全文を読む スポンサード リンク
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