An EKG, or Electrocardiogram, is a diagnostic tool that records the electrical activity of the heart over a period of time. Here's detailed information on the subject:
History and Development
The origins of the EKG trace back to the late 19th century:
- In 1887, Augustus Waller, a physiologist, recorded the first human electrocardiogram using a capillary electrometer.
- The term "Electrocardiogram" was coined by Willem Einthoven, who in 1901 developed the Einthoven's Galvanometer, which significantly improved the recording process. Einthoven was awarded the Nobel Prize in Physiology or Medicine in 1924 for this work.
- By the 1930s, portable EKG machines were developed, allowing for broader clinical use.
How It Works
An EKG functions by detecting and amplifying the tiny electrical changes on the skin that are caused when the heart muscle depolarizes during each heartbeat. Here is the basic process:
- Electrodes Placement: Small, sticky sensors called electrodes are attached to the skin on the chest, arms, and legs.
- Electrical Activity: The heart's electrical activity causes small electrical changes on the skin that are picked up by these electrodes.
- Recording: The electrical signals are then amplified and recorded by the EKG machine, producing a graphical representation of the heart's electrical activity known as an electrocardiogram waveform.
Clinical Uses
The EKG is used for various purposes:
- Diagnosis: It helps in diagnosing a range of heart conditions including arrhythmias, myocardial infarction (heart attack), and conduction disturbances.
- Monitoring: Continuous EKG monitoring is common in hospital settings, particularly in intensive care units, to track heart rhythm.
- Pre-surgical Assessment: Used to assess the heart's condition before surgery.
- Exercise Stress Testing: To evaluate the heart's response to physical stress.
Waveforms and Interpretation
The EKG tracing consists of waves named P, QRS, and T:
- P wave: Represents atrial depolarization.
- QRS complex: Indicates ventricular depolarization.
- T wave: Reflects ventricular repolarization.
Limitations and Advancements
While EKG is invaluable, it has limitations:
- It provides a snapshot in time; intermittent conditions might be missed.
- Artifacts from movement or other electrical interference can affect the recording.
Advancements include:
- Holter monitors for continuous monitoring.
- Event recorders for capturing intermittent symptoms.
- Telemetry systems for real-time remote monitoring.
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