Final answer:
An electrocardiogram (EKG or ECG) is a medical test that records the heart's electrical activity and is used to diagnose conditions like tachycardia, where the heart beats abnormally fast. The test uses electrodes placed on the skin to pick up electrical impulses, which are carefully analyzed to detect any irregular function.
Step-by-step explanation:
An electrocardiogram (EKG or ECG) is a detailed record of the heart's electrical activity. It is commonly used to diagnose a condition known as tachycardia, which is characterized by an abnormally fast heart rate. By using surface electrodes, the ECG captures the electrical impulses of the cardiac muscle as they depolarize and repolarize during the heart's beating cycle. A standard ECG typically implements 3, 5, or 12 leads to monitor these impulses, providing a comprehensive map of the heart's function. The 12-lead ECG is particularly informative, as it uses 10 electrodes placed on the patient's skin at standard locations to deliver a more thorough analysis.
These electrical impulses result in currents that travel through the body and can be measured via electrodes on the skin. Irregularities in timing and pattern of the heart's electrical signals, including those seen in tachycardia, can be identified through careful examination of the ECG's tracings. Nowadays, for continuous recording, a patient may wear a Holter monitor, a portable device that provides ongoing ECG monitoring, which is essential for detecting episodic cardiac events or monitoring heart rate over a longer duration in the patient's normal routine.