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Related Concept Videos

Dysrhythmias III: Characteristics of Dysrhythmias01:29

Dysrhythmias III: Characteristics of Dysrhythmias

Dysrhythmias, also known as arrhythmias, are irregular heart rhythms that result from abnormal electrical activity in the heart, affecting its ability to circulate blood efficiently. Tachyarrhythmias, a subset of dysrhythmias, are characterized by abnormally fast heart rates exceeding 100 beats per minute. Here are some types of tachyarrhythmias with their distinct ECG features:Sinus Tachycardia:Sinus tachycardia presents a regular heart rhythm with an increased rate of 101-180 beats per minute.
Disturbances in Heart Rhythm01:29

Disturbances in Heart Rhythm

Arrhythmia or dysrhythmia refers to an abnormal heart rhythm caused by a defect in the heart's conduction system. It can cause the heart to beat irregularly, too quickly, or too slowly, leading to symptoms like chest pain, shortness of breath, and fainting. Factors such as stress, caffeine, alcohol, nicotine, cocaine, certain drugs, congenital defects, diseases, and electrolyte abnormalities can trigger arrhythmias.
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Dysrhythmias IV: Characteristics of Bradyarrhythmias01:18

Dysrhythmias IV: Characteristics of Bradyarrhythmias

Bradyarrhythmias are cardiac rhythm disorders characterized by a slower-than-normal heart rate, typically defined as fewer than 60 beats per minute. Some of which are discussed here:Sinus BradycardiaSinus bradycardia presents a heart rate lower than 60 beats per minute, with a regular rhythm originating from the SA node. The ECG typically shows normal P waves preceding each QRS complex, a normal PR interval (0.12 to 0.20 seconds), and a normal QRS duration (0.06 to 0.10 seconds).First-Degree AV...
Correlation between ECG and Cardiac Cycle01:25

Correlation between ECG and Cardiac Cycle

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...
Cardiac Action Potential01:30

Cardiac Action Potential

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
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias01:25

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

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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Optimization of Transesophageal Atrial Pacing to Assess Atrial Fibrillation Susceptibility in Mice
08:05

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Inappropriate mode switch consecutive to P-wave double counting.

Vincent Ganiere1, Romain Cassagneau, Haran Burri

  • 1Cardiology Department, University Hospital of Grenoble, Grenoble, France. vincentganiere@yahoo.fr

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
|June 30, 2011
PubMed
Summary
This summary is machine-generated.

Pacemaker mode-switching issues can arise from P-wave double counting, a rare event caused by double potentials on the atrial electrogram. This case highlights the importance of considering this phenomenon in pacemaker diagnostics.

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Area of Science:

  • Cardiology
  • Biomedical Engineering
  • Electrophysiology

Background:

  • Dual-chamber pacemakers are crucial for managing bradyarrhythmias.
  • Pacemaker mode switching is a programmed feature to adapt pacing mode to the patient's intrinsic activity.
  • Inappropriate mode switching can lead to suboptimal pacing and potential adverse events.

Observation:

  • A patient with a dual-chamber pacemaker experienced recurrent inappropriate mode switches.
  • The atrial electrogram revealed a double potential, leading to P-wave double counting.
  • This P-wave double counting was identified as the cause of the pacemaker's mode switching.

Findings:

  • P-wave double counting, caused by atrial electrogram double potentials, is a rare but significant cause of inappropriate pacemaker mode switching.
  • This phenomenon can mimic other causes of mode switch, necessitating careful electrogram analysis.
  • The differential diagnosis for such events includes lead issues, far-field R-wave sensing, and intrinsic arrhythmias.

Implications:

  • Accurate diagnosis of P-wave double counting is essential for effective pacemaker management.
  • Pacemaker reprogramming or lead revision may be necessary to resolve this issue.
  • Further research into the mechanisms and prevalence of P-wave double counting in pacemaker patients is warranted.