Electrocardiography

What is Electrocardiography?

Electrocardiography (ECG or EKG from ) is the process of recording the electrical activity of the heart over a period of time using electrodes placed on a patient's body. These electrodes detect the tiny electrical changes on the skin that arise from the heart muscle depolarizing during each heartbeat.

In a conventional 12 lead ECG, ten electrodes are placed on the patient's limbs and on the surface of the chest. The overall magnitude of the heart's electrical potential is then measured from twelve different angles ("leads") and is recorded over a period of time (usually 10 seconds). In this way, the overall magnitude and direction of the heart's electrical depolarization is captured at each moment throughout the cardiac cycle. The graph of voltage versus time produced by this noninvasive medical procedure is referred to as an electrocardiogram (abbreviated ECG or EKG).

During each heartbeat, a healthy heart will have an orderly progression of depolarization that starts with pacemaker cells in the sinoatrial node, spreads out through the atrium, passes through the atrioventricular node and then spreads throughout the ventricles. This orderly pattern of depolarization gives rise to the characteristic ECG tracing. To the trained clinician, an ECG conveys a large amount of information about the structure of the heart and the function of its electrical conduction system. Among other things, an ECG can be used to measure the rate and rhythm of heartbeats, the size and position of the heart chambers, the presence of any damage to the heart's muscle cells or conduction system, the effects of cardiac drugs, and the function of implanted pacemakers.

Questions and answers on "Electrocardiography"

A friend related to me that if she feels intensely sad or joyful she has recently experienced falls where she feels paralyzed from the neck down...

doctor1 MD

Brief Answer:
Cataplexy is a possible cause

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I read your question carefully and I appreciate your concern about your friend.

That...

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I get heart throbs and feel week from time to time.

doctor1 MD

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You need thorough check-up.

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Hello Giniar4114
Thanks for writing to XXXXXXX

Heart throb may be due to problems...

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My 49 yr old son is experiencing periodic, temporary blindness, anywhere from 5 min to up to 25 min. He's not seen a Dr. In yrs. He drinks bet 24...

doctor1 MD

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Thorough ocular examination required.

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Welcome to HealthcareMagic.com,

The condition you have described here...

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