What is an Electrocardiogram (ECG)?

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Last updated: February 18, 2025View editorial policy

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From the Guidelines

Definition of Electrocardiogram (ECG)

An electrocardiogram (ECG) is a fundamental diagnostic tool that records the electrical activity of the heart, utilizing electrodes placed on the skin to detect the heart's rhythmic patterns 1.

  • The ECG has become the most commonly conducted cardiovascular diagnostic procedure and is indispensable for the diagnosis and prompt initiation of therapy in patients with acute coronary syndromes and is the most accurate means of diagnosing intraventricular conduction disturbances and arrhythmias 1.
  • Its interpretation may lead to the recognition of electrolyte abnormalities, particularly of serum potassium and calcium, and permit the detection of some forms of genetically mediated electrical or structural cardiac abnormalities 1.
  • The ECG is routinely used to:
    • Monitor patients treated with antiarrhythmic and other drugs
    • Assess patients undergoing noncardiac surgery
    • Screen individuals in high-risk occupations 1
  • The ECG tracing is then analyzed to assess heart rate, rhythm, and morphology, with abnormal findings potentially indicating conditions such as arrhythmias, ischemia, or conduction disorders.
  • The ECG is a non-invasive diagnostic test that can be performed quickly and easily, typically requiring approximately 5-10 minutes to complete, and does not require any specific medication or preparation.

From the Research

Definition and Purpose of Electrocardiogram (ECG)

  • An Electrocardiogram (ECG) is a low-cost, simple, fast, and non-invasive test that reflects the heart's electrical activity and provides valuable diagnostic clues about the health of the entire body 2.
  • The ECG is used to assess heart disease, including arrhythmias, and is fundamental for the evaluation of cardiac conditions 3.
  • It can be used to identify patients at risk, provide accurate diagnosis, and guide therapy for various cardiac abnormalities 4, 5.

Applications of ECG

  • ECG has been widely used in various biomedical applications such as arrhythmia detection, disease-specific detection, mortality prediction, and biometric recognition 2.
  • It is used to diagnose and monitor non-cardiac diseases such as stroke, migraine, pancreatitis, and pulmonary embolism 6.
  • ECG is also used in cardiac resynchronization therapy (CRT) to provide insights into the mechanism of the therapy and guide therapeutic decision-making 3.

Characteristics of ECG

  • A standard ECG provides low-resolution projections of cardiac electrical activity on the body surface 4.
  • Electrocardiographic imaging (ECGi) is a non-invasive multi-lead ECG-type imaging tool that enhances conventional 12-lead ECG and provides diagnostic insights regarding the mechanistic basis of arrhythmias and the location of arrhythmia origin 3.
  • ECG signals can be analyzed using various techniques, including preprocessing, feature extraction, and classification, to detect and classify arrhythmias 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Intelligent Electrocardiogram Analysis in Medicine: Data, Methods, and Applications.

Chinese medical sciences journal = Chung-kuo i hsueh k'o hsueh tsa chih, 2023

Research

Electrocardiographic imaging for cardiac arrhythmias and resynchronization therapy.

Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology, 2020

Research

Arrhythmia detection and classification using ECG and PPG techniques: a review.

Physical and engineering sciences in medicine, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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