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what is ECG?Explain it?

 ECG is a graphic display or recording of the electrical variations produced by heart muscle during a cardiac cycle. The activity of the heart create an electrical field which is conducted through the surrounding body tissues to the surface of the body.

 

normal pulse rate using ecg

 

Two electrodes are placed on the surface of the body at a distance and the potential difference between the points is measured. The sequence of events during contraction and relaxation of the heart muscle are graphically presented as voltage displacement on the Y-axis with time on the X-axis. This tracing or recording is called an electrocardiogram.

 

normal ecg view

 

Each ECG has 5 consecutive waves namely three upward deflections and two downward waves. They are named as PQRST.

The P Wave represents the first upward deflection of the ECG. It takes place when the impulse spreads over the atrial chambers. Its average duration is about 0.1 second. It represents the depolarization of the atrial musculature.

The QRS complex is the combined result of the repolarization of the atria and the depolarization of the ventricles.

 

electrocardiogram with explanation

 

The sequence of events in the cardiac cycle starting with the onset of atrial systole. Part of the subsequent cycle is shown. PA, blood pressure in the pulmonary artery; RA, right atrail pressure; La, left atrid pressure.

The T-wave is the wave of ventricular repolarization. It has a duration of 0.27 seconds.

The shape and polarity of each of the above features varies with the location of the electrode with respect to the heart and a diagram in made based on readings taken from several electrode locations.

Uses of ECG

In healthy individuals, the ECG remains reasonably constant, even though the heart rate changes with the demands of the body.

The electrical activity of the heart shows changes under the following situations.

a) Change in ionic environment of the heart

b) A defect in the conduction system of the heart

c) damage to muscle fibres due to decreased blood supply

d) ECG is used for detecting several heart diseases. It is a non invasivetechnique.

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View Full Answer

Electrocardiography  interpretation of theelectrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body. The recording produced by this noninvasive procedure is termed as electrocardiogram . An ECG test records the electrical activity of the heart.

ECG is used to measure the rate and regularity of heartbeats, as well as the size and position of the chambers, the presence of any damage to the heart, and the effects of drugs or devices used to regulate the heart, such as a pacemaker. See also stress test and Holter monitor (24h).

Most ECGs are performed for diagnostic or research purposes on human hearts, but may also be performed on animals, usually for diagnosis of heart abnormalities or research.

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 It is important to note that an electrocardiogram is not foolproof. It is possible to have an ECG that is normal but still be afflicted by heart problems. The opposite can also be true - sometimes the graph from the ECG can show problems where there are none at all. Atherosclerosis, which is the buildup of fat in artery walls that causes blocked or narrowed coronary arteries, is not always revealed with a resting ECG due to the fact that when the heart is at rest, it is receiving enough oxygen. In this instance, a doctor may decide that a stress ECG that looks at the condition of the blood vessels of the heart is in order. A stress ECG is done while a patient is either riding a stationary bike or exercising on a treadmill.

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Electrocardiography is a transthoracic (across the thorax or chest) interpretation of the electricalactivity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body.[1] The recording produced by this noninvasive procedure is termed as electrocardiogram . An ECG test records the electrical activity of the heart.

ECG is used to measure the rate and regularity of heartbeats, as well as the size and position of the chambers, the presence of any damage to the heart, and the effects of drugs or devices used to regulate the heart, such as a pacemaker.

Most ECGs are performed for diagnostic or research purposes on human hearts, but may also be performed on animals, usually for diagnosis of heart abnormalities or research.

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It is a device used for measuring temprature
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It is a thing that take a record of our heart beat and other yhings
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