General theory, history and development
Echocardiography (M-mode) was first described by Dr. Inge Edler (Fig. 2.1) working at the university of Lund, Sweden, in 1954. The term echocardiography refers to a group of tests that use ultrasound to examine the heart and record information in the form of echoes, i.e., reflected sonic waves.1 The upper limit for audible sound is 20 KHz. The sonic frequency used for echocardiography ranges from 1 to 10 MHz (these are known as ultrasound waves). The characteristics of a sound wave can be expressed as a sine wave. The distance between two similar areas along the wave path (e.g., the distance that wave travels during a single cycle) is termed a wavelength (λ). The number of the wavelengths per unit time is the frequency (f) of the sound wave, which is measured in cycles per seconds (cps, also called Hertz [Hz]). One of the fundamental principles in sound physics is:
where c is the speed of sound in a medium, f is the frequency of the sound wave, and λ is the wavelength of the sound in the medium. The frequency of the sound depends only on the source that is producing it, but the speed of sound (and hence of wavelength) varies from one medium of propagation to another.1
$$c = f\lambda $$
KeywordsContinuous Wave Transesophageal Echocardiography Doppler Echocardiography Doppler Frequency Shift Ventricular Systolic Pressure
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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- 2.Feigenbaum H. Echocardiography. 5th ed. Lea & Febiger, Philadelphia, 1994Google Scholar
- 4.Saini VD, Nanda NC, Maulik D. Basic principles of ultrasound and Doppler effect. In: Nanda NC, ed. Doppler echocardiography. 2nd ed. Lea & Febiger, Philadelphia, London, pp 3–24, 1993Google Scholar
- 5.Kolev N. Assessment of left ventricular function in ischemic heart disease using pulsed Doppler transmitral blood flow during exercise. J Cardiovasc Diag Proc (NY) 11: 15–18, 1990Google Scholar
- 10.Saini VD, Nanda NC, Maulik D. Principles of Doppler ultrasound implementation. In: Nanda NC, ed. Doppler echocardiography. 2nd ed. Lea & Febiger, Philadelphia, pp 18–23, 1993Google Scholar
- 11.West SR, Feigenbaum H, Armstrong WF, Green D, Dillon JC. Split screen simultaneous digital imaging of rest and stress echocardiogram (Abstr). J Am Coll Cardiol 3: 563, 1984Google Scholar
- 13.Marganelli V, D’Ambrosio G, Carella L, Iliseto S, Rizzon P. A digital cine loop technology—a new tool for the evaluation of wall motion abnormalities. In: Iliseto S, Rizzon, Roelandt JRTC, eds. Ultrasound in coronary artery disease. Kluwer Academic Publ, Dordrechts, pp 95–99, 1991Google Scholar
- 23.Flachkampf FA, Hoffmann R, Verlande M, Schneider W, Ameling W, Hanrath P. Initial experience with multiplane transesophageal echotransducer: assessment of diagnostic potential. Eur J Cardiol 13: 1201–1206, 1992Google Scholar
- 24.Kolev N, Ihra G, Leitner K, Spiss CK, Zimpfer M. Improved detection of perioperative myocardial ischemia with multiplane (Hewlett Packard) transesophageal scanning: Two-dimensional biplane and transmitral Doppler echocardiography. J Cardiovasc Diag Proc (NY) (in press) 1994Google Scholar
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