Electrocardiography (ECG) measures the electrical activity of the heart through electrodes placed on the skin. No electricity is sent into the body; the ECG simply records the heart's natural electrical impulses.
Here's a breakdown of the process:
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Electrode Placement: Small, adhesive electrodes are attached to specific locations on the patient's arms, legs, and chest. These locations are standardized to ensure consistent and comparable readings.
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Lead Wires: Each electrode is connected to an ECG machine via lead wires. These wires transmit the electrical signals detected by the electrodes to the ECG machine.
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Signal Detection and Amplification: The electrodes detect the tiny electrical changes on the skin caused by the heart's activity. The ECG machine amplifies these signals to make them easier to analyze.
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Signal Processing and Interpretation: The ECG machine processes the amplified signals and converts them into a visual representation of the heart's electrical activity over time. Sophisticated algorithms help in the interpretation, but a trained professional (like a doctor or cardiologist) reviews the ECG to identify any abnormalities.
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Output: The ECG machine then displays and prints out the data as a waveform on graph paper or digitally on a computer screen. This waveform is the electrocardiogram, which shows the heart's rhythm, rate, and electrical conduction pathways.
Key Points:
- ECG is a non-invasive procedure.
- It measures the electrical activity, not the mechanical pumping action of the heart directly (though the electrical activity triggers the pumping).
- Different lead placements provide different "views" of the heart's electrical activity, allowing for a comprehensive assessment.
The resulting ECG tracing helps healthcare professionals diagnose a wide range of heart conditions, including arrhythmias (irregular heartbeats), heart attacks, and enlarged heart chambers.
