Chest Pain Cause Diagnostic Test Ecg Ekg

An electrocardiogram (ECG) is sometimes abbrviated as EKG, from the German term Elektrokardiogramm. Often, doctors will use an electrocardiogram to detect signs of an irregular heartbeat. However, physicians can also use an ECG to diagnose such conditions as angina, atrial fibrillation and heart attack.

The ECG (or EKG) is based on a very simple concept: The heart generates electric impulses that cause it to beat. A healthy heart usually has a regular heartbeat that can be represented graphically in a particular electrical wave pattern. Irregular heart rhythms and their corresponding waveforms can be interpreted by comparing them to normal ECG graphs. Discrepancies between normal ECGs and abnormal ECGs may indicate an irregular heartbeat or other conditions.

The Electrocardiogram Procedure

An electrocardiogram test is a painless procedure that usually requires minimal activity on the part of the patient. Often, the patient will be asked to lie down on an exam table while an ECG technician attaches 10 electrodes to the patient’s body. Six electrodes will be placed across the patient’s chest. The four remaining electrodes will be placed on the patient’s arms and legs.

During the ECG, the patient will need to remain still and hold his breath for short periods of time. Sometimes, an electrocardiogram test is performed while you’re exercising or performing some other sort of activity in order to evaluate the heart’s ability to cope with stress. When an ECG is performed in this manner, it is called a stress test.

ECG Side Effects

While the ECG is considered a harmless procedure, some patients will develop localized rashes where the electrodes were attached to their bodies. These rashes will generally disappear shortly after the electrodes have been removed.

Interpreting of ECG Results

ECG results are depicted as a graph. Six particular components of the graph are critical to the interpretation of the ECG:

  1. P Wave: In normal ECG results, the P wave is smooth, positive and lasts 0.12 seconds or less. This represents the contraction of the atria, the two upper chambers of the heart.
  2. PR Interval: The PR interval is the length of time between the P wave and the start of the QRS complex (see below). The PR interval data indicates the quality of atrial electric conduction.
  3. QRS Complex: The QRS complex measures the time it takes for the ventricles, the major pumping chambers of the heart, to contract, usually between 0.04 and 0.12 seconds.
  4. T Wave: The T wave shows doctors how long it takes the ventricles to return to a resting state after a contraction.
  5. ST Segment: The ST segment measures the length of ventricular contraction.
  6. QT Interval: The QT interval measures from the beginning of the QRS complex to the end of the T wave, or from the beginning of ventricular contraction to the end of the ventricular resting state. ECG results for the QT interval vary depending on age, gender, electrolyte balance, medication and heart attack damage.

In order to diagnose abnormalities in your heart, your doctor will closely examine all components of your ECG. If your ECG results look abnormal, you might need to undergo further testing.


Cohen, James S. (reviewed October 5, 2005). Retrieved October 23, 2007, from the eMedicineHealth Web site: