Related Experiment Video
Updated: May 4, 2026

Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation
Published on: July 20, 2022
[Approximate entropy of electrocardiogram signals in atrial fibrillation]
1Department of Pathobiological Science and Technology, School of Health Science, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan. aoitoriwosagasite77@yahoo.co.jp
Insights
Approximate entropy (ApEn) analysis of electrocardiogram (ECG) signals reveals higher randomness in patients with atrial fibrillation (Af). This method effectively assesses the nonlinear properties of ECG, aiding in Af evaluation.
Area of Science:
- Cardiology
- Biomedical Engineering
- Nonlinear Dynamics
Context:
- Atrial fibrillation (Af) is a prevalent cardiac arrhythmia associated with a significant risk of thromboembolism, necessitating anticoagulant therapy.
- Electrocardiogram (ECG) signals reflect the heart's electrical activity and can be analyzed for complex patterns.
- Understanding the nonlinear properties of cardiac signals may offer new diagnostic insights.
Purpose:
- To investigate the utility of Approximate Entropy (ApEn) in quantifying the complexity and randomness of cardiac electrical activity in patients with chronic atrial fibrillation (Af).
- To compare ApEn values derived from ECG signals between individuals with and without Af.
- To assess the influence of anti-arrhythmic drug administration on ECG signal complexity as measured by ApEn.
Summary:
- The study calculated Approximate Entropy (ApEn) for ECG signals from 29 subjects without arrhythmia and 12 patients with chronic Af.
- Mean ApEn was significantly higher in the chronic Af group (0.556 +/- 0.169) compared to the control group (0.347 +/- 0.119) (p < 0.002).
- ApEn was also significantly higher in patients not on anti-arrhythmic drugs (0.687 +/- 0.033) versus those on medication (0.516 +/- 0.209) (p < 0.05), indicating ApEn's effectiveness in evaluating ECG nonlinear properties and assessing Af randomness.
Impact:
- Approximate Entropy (ApEn) serves as a valuable tool for evaluating the nonlinear characteristics of ECG signals.
- This analysis provides a quantitative measure to assess the randomness associated with chronic atrial fibrillation.
- Findings suggest ApEn could enhance the diagnostic assessment of Af and potentially guide treatment strategies.
Abstract:
Atrial fibrillation (Af) is a common arrhythmia and disorder of the rhythm of electrical activation of the cardiac atria. There is a high risk of thromboembolism in patients with Af. Therefore, it is an indication for anticoagulant therapy. The approximate entropy (ApEn) of electrocardiogram (ECG) signals was calculated in 29 subjects without arrhythmia and 12 patients with chronic Af. The mean ApEn in the group without arrhythmia was 0.347 +/- 0.119, and that of the chronic Af group was 0.556 +/- 0.169. ApEn was significantly higher in the chronic Af group than in the no arrhythmia group (p < 0.002). The average ApEn was significantly higher in the group not administered anti-arrhythmic drugs (0.687 +/- 0.033) than that in the group administered anti-arrhythmic drugs (0.516 +/- 0.209) (p < 0.05). We found that ApEn was effective in evaluating the nonlinear property and ApEn of ECG signals, enabling assessment of the randomness of chronic Af.
Related Concept Videos
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Dysrhythmias III: Characteristics of Dysrhythmias
Dysrhythmias IV: Characteristics of Bradyarrhythmias
Electrocardiogram Fundamentals
An electrocardiogram (ECG) is a diagnostic tool for identifying cardiac conditions such as arrhythmias, conduction abnormalities, and myocardial ischemia.
Definition
An electrocardiogram (ECG) visualizes the heart's electrical activity by tracing the electrical movement associated with each heartbeat on a graph or monitor. As the heart beats, an electrical wave passes through it, correlating with the cardiac cycle events.
Parts of an ECG
An ECG utilizes electrodes on the skin...
Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...

