Electrocardiograms – EKG
Description: Electrocardiograms is a test that is performed that records and documents movement of the heart through electrical conduction illustrated by line tracings with different waves. Patches (electrodes) are places on several areas of the body, and through the wires connected to the electrodes, the electrical signals from the heart are displayed in “wavy lines” that a healthcare professional may interpret. There is no pain associated with the ECG procedure. An ECG test may be needed to be performed to assess damage to the heart, measure the beat and normality of one’s heart, effects of drugs, devices, or outcomes of surgeries on the heart, and/or the size and position of the heart chambers. Recently created technology now allows emergency responders to transmit real-time data from the ambulance to the hospital reducing the catheterization procedure by up to 20 minutes. The new technology has also decreased the error margin usually associated with transferring information from the response team to the doctors. With the help of the LifeNet receiving station technology physicians can monitor EKG activity on their smartphones allowing them to keep up with the patients vitals until they arrive.
Applications: Electrocardiograms – EKG Strips

How to read: The strips are composed of “small” and “large” squares. One “small” square represents 0.04 seconds, and five “small” squares make up one “large” square that represents 0.2 seconds. Most EKG readings are read from a 3 second strip. The waves that appear on the strips are broken down to a P wave, QRS segment, and T wave. The P wave indicates atrial depolarization, and should be upright and rounded. The QRS segment should be less then .12 seconds (3 “small” boxes) and indicates ventricular depolarization. The P-R interval should measure between .12-.20 seconds (3-5 “small” boxes). The T wave indicates ventricular repolarization, should be rounded and asymmetrical. If the T wave is “pointy”, this could be an indicator of hyperkalemia, and measures of the potassium level should be immediately checked.
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Who Needs an Electrocardiogram?
Your doctor may recommend an electrocardiogram (EKG) if you have signs or symptoms that suggest a heart problem. Examples of such signs and symptoms include:
  • Chest pain
  • Heart pounding, racing, or fluttering, or the sense that your heart is beating unevenly
  • Breathing problems
  • Tiredness and weakness
  • Unusual heart sounds when your doctor listens to your heartbeat
You may need to have more than one EKG so your doctor can diagnose certain heart conditions.
An EKG also may be done as part of a routine health exam. The test can screen for early heart disease that has no symptoms. Your doctor is more likely to look for early heart disease if your mother, father, brother, or sister had heart disease—especially early in life.
You may have an EKG so your doctor can check how well heart medicine or a medical device, such as a pacemaker, is working. The test also may be used for routine screening before major surgery.
Your doctor also may use EKG results to help plan your treatment for a heart condition.

Special Types of Electrocardiogram

The standard EKG described above, called a resting 12-lead EKG, only records seconds of heart activity at a time. It will show a heart problem only if the problem occurs during the test.
Many heart problems are present all the time, and a resting 12-lead EKG will detect them. But some heart problems, like those related to an irregular heartbeat, can come and go. They may occur only for a few minutes a day or only while you exercise.
Doctors use special EKGs, such as stress tests and Holter and event monitors, to help diagnose these kinds of problems.

Stress Test

Some heart problems are easier to diagnose when your heart is working hard and beating fast. During stress testing, you exercise to make your heart work hard and beat fast while an EKG is done. If you can't exercise, you'll be given medicine to make your heart work hard and beat fast.


Holter and Event Monitors

Holter and event monitors are small, portable devices. They record your heart's electrical activity while you do your normal daily activities. A Holter monitor records your heart's electrical activity for a full 24- or 48-hour period.
An event monitor records your heart's electrical activity only at certain times while you're wearing it. For many event monitors, you push a button to start the monitor when you feel symptoms. Other event monitors start automatically when they sense abnormal heart rhythms.

What Does an Electrocardiogram Show?
Many heart problems change the heart's electrical activity in distinct ways. An electrocardiogram (EKG) can help detect these heart problems.
EKG recordings can help doctors diagnose heart attacks that are in progress or have happened in the past. This is especially true if doctors can compare a current EKG recording to an older one.
An EKG also can show:
  • Lack of blood flow to the heart muscle
  • A heartbeat that's too fast, too slow, or irregular
  • A heart that doesn't pump forcefully enough
  • Heart muscle that's too thick or parts of the heart that are too big
  • Birth defects in the heart
  • Problems with the heart valves
  • Inflammation of the sac that surrounds the heart
An EKG can reveal whether the heartbeat starts in the correct place in the heart. The test also shows how long it takes for electrical signals to travel through the heart. Delays in signal travel time may suggest heart block or long QT.

Related Terminology:
- Electrocardiogram, EKG, ECG

Citations/References - Web Sources:

http://www.webmd.com/heart-disease/electrocardiogram
http://www.nhlbi.nih.gov/health/health-topics/topics/ekg/during.html
http://www.jems.com/article/news/texas-trauma-council-unveils-n
http://www.stlamerican.com/your_health_matters/health_studies/article_710cedc2-7ea7-11e1-aeff-0019bb2963f4.html