Electrocardiogram
A recording of the electrical activity of the heart. An electrocardiogram is a simple, non-invasive procedure. Electrodes are placed on the skin of the chest and connected in a specific order to a machine that, when turned on, measures electrical activity all overaround the heart. Output is usually in the form of a long scroll of paper displaying a printed graph of activity. Newer models output the data directly to a computer and screen, although a print-out may still be made.To take a specific situation, the initial diagnosis of a heart attack is usually made by a combination of clinical symptoms and characteristic electrocardiogram (EKG) changes. The EKG can detect areas of muscle ischemia (muscle deprived of oxygen) and/or dead tissue in the heart.
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Graphic record of the heart's integrated action currents obtained with the electrocardiograph displayed as voltage changes over time. [electro- + G. kardia, heart, + gramma, a drawing]
- concordant changes e. the presence of more than one waveform change, each in the same direction (polarity).
- discordant changes e. the presence of more than one waveform change, each in a different direction (polarity).
- scalar e. (skal′ar) electrocardiographic lead output that can be displayed on one plane of the body in contradistinction to vector e. in which the display is on two or more planes.
- unipolar e. an e. taken with the exploring electrode placed on the chest overlying the heart or upon a single limb, the indifferent (“zero” potential) electrode being the central terminal.

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elec·tro·car·dio·gram -'kärd-ē-ə-.gram n the tracing made by an electrocardiograph also the procedure for producing an electrocardiogram

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n.
a recording of the electrical activity of the heart on a moving paper strip. The ECG tracing is recorded by means of an apparatus called an electrocardiograph (see electrocardiography). It aids in the diagnosis of heart disease, which may produce characteristic changes in the ECG.

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elec·tro·car·dio·gram (e-lek″tro-kahrґde-o-gram″) [electro- + cardiogram] a graphic tracing of the variations in electrical potential caused by the excitation of the heart muscle and detected at the body surface. The normal electrocardiogram is a scalar representation that shows deflections resulting from atrial and ventricular activity as changes in the magnitude of voltage and polarity (positive and negative) with time. The first deflection, the P wave, is due to excitation of the atria; the QRS complex of deflections, to excitation (depolarization) of the ventricles; and the T wave, to recovery of the ventricles (repolarization). Abbreviated ECG or EKG. See also lead2 and see terms under wave, complex, and interval.

Normal electrocardiogram.


Medical dictionary. 2011.

Look at other dictionaries:

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  • Electrocardiogram — An electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm ) is a noninvasive transthoracic graphic produced by an electrocardiograph, which records the electrical activity of the heart over time. Its name is made of… …   Wikipedia

  • electrocardiogram — n. to do; have an electrocardiogram * * * have an electrocardiogram to do …   Combinatory dictionary

  • electrocardiogram — UK [ɪˌlektrəʊˈkɑː(r)dɪəˌɡræm] / US [ɪˌlektroʊˈkɑrdɪəˌɡræm] noun [countable] Word forms electrocardiogram : singular electrocardiogram plural electrocardiograms an ECG …   English dictionary

  • electrocardiogram — cardiogram car di*o*gram , n. [Gr. kardi a heart + gram.] (Physiol.) Any instrumental record made of heart activity, especially the curve or tracing made by a cardiograph. Sometimes used synonymously with {electrocardiogram}. [Webster 1913 Suppl …   The Collaborative International Dictionary of English

  • electrocardiogram — noun Date: circa 1904 the tracing made by an electrocardiograph; also the procedure for producing an electrocardiogram …   New Collegiate Dictionary

  • electrocardiogram — [[t]ɪle̱ktroʊkɑ͟ː(r)dioʊgræm[/t]] electrocardiograms N COUNT If someone has an electrocardiogram, doctors use special equipment to measure the electric currents produced by that person s heart in order to see whether it is working normally …   English dictionary

  • electrocardiogram — /i lek troh kahr dee euh gram /, n. Med. the graphic record produced by an electrocardiograph. Abbr.: EKG, ECG Also called cardiogram. [1900 05; ELECTRO + CARDIOGRAM] * * * …   Universalium

  • electrocardiogram — noun /əˌlɛktrəˈkɑrdiəˌɡræm/ The curve drawn or traced by an electrocardiograph. Syn: cardiogram …   Wiktionary

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