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Related Concept Videos

Correlation between ECG and Cardiac Cycle01:25

Correlation between ECG and Cardiac Cycle

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The electrical signals recorded on an electrocardiogram (ECG) occur before the mechanical processes of contraction and relaxation during the 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...
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Cardiac Action Potential01:30

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Cardiac action potentials are essential for proper heart function, enabling the rhythmic contractions needed for adequate blood circulation. Nodal cells and Purkinje fibers, specialized for electrical conduction, generate these action potentials.
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
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Electrophysiology of Normal Cardiac Rhythm01:19

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The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase...
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Electrocardiogram01:29

Electrocardiogram

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An electrocardiogram (ECG or EKG) is a critical diagnostic tool that records the electrical signals produced by the heart during each heartbeat. This recording is achieved through electrodes placed strategically on the arms, legs, and chest. The electrocardiograph amplifies these signals and produces 12 distinct tracings, offering a comprehensive understanding of the heart's electrical activity.
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and...
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ECG Interpretation of Rhythms01:24

ECG Interpretation of Rhythms

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An electrocardiogram (ECG)graphically represents the heart's electrical activity on ECG paper or a monitor.
Components of the Electrocardiogram
The primary components of a normal ECG waveform in Normal sinus rhythm(NSR) include the P wave, PR interval, QRS complex, ST segment, T wave, and occasionally a U wave.
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The horizontal axis measures time and rate, and the vertical axis measures amplitude or voltage....
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ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias01:25

ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias

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Arrhythmia is a condition characterized by an irregular heart rhythm, with ECG changes that differ based on its origin and nature. The types of arrhythmias discussed below include atrial, junctional, and ventricular arrhythmias.Atrial ArrhythmiasPremature Atrial Complexes (PACs): PACs are early atrial beats caused by stress, caffeine, alcohol, electrolyte imbalances, hypoxia, hyperthyroidism, or certain medications (e.g., bronchodilators and decongestants). The ECG shows early P waves with an...
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Related Experiment Video

Updated: Mar 10, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
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ECG Patterns In Cardiac Resynchronization Therapy.

Antonius van Stipdonk1, Sofieke Wijers2, Mathias Meine2

  • 1Department of Cardiology, Maastricht University Medical Center.

Journal of Atrial Fibrillation
|December 14, 2016
PubMed
Summary
This summary is machine-generated.

Understanding electrical activation patterns is key to improving cardiac resynchronization therapy (CRT) outcomes. Analyzing QRS morphology on electrocardiograms helps identify and address non-response issues in heart failure patients.

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Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Devices

Background:

  • Cardiac resynchronization therapy (CRT) is a standard treatment for heart failure.
  • A significant number of patients do not respond optimally to CRT, necessitating further investigation.
  • Understanding ventricular electrical activation is crucial for effective CRT.

Approach:

  • This review examines existing literature on QRS morphology in CRT.
  • The study focuses on interpreting the 12-lead electrocardiogram (ECG) to understand activation patterns.
  • Analysis of ECG findings aims to identify reasons for suboptimal CRT response.

Key Points:

  • QRS morphology provides insights into intrinsic ventricular activation.
  • Interpreting QRS morphology during biventricular, right, and left ventricular pacing is essential.
  • ECG analysis can reveal causes of non-response to CRT.

Conclusions:

  • Optimizing CRT requires a thorough understanding of electrical activation patterns.
  • QRS morphology analysis using the 12-lead ECG is a valuable tool for improving CRT efficacy.
  • Addressing suboptimal treatment through ECG interpretation can enhance patient outcomes in heart failure management.