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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.
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...
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 II: Classification of Tachyarrhythmias01:28

Dysrhythmias II: Classification of Tachyarrhythmias

Tachyarrhythmias are a type of dysrhythmia where the heart rate exceeds 100 beats per minute. Here are some common types of tachyarrhythmias:Sinus TachycardiaSinus tachycardia originates from increased impulses from the sinus node, leading to an elevated heart rate. It is often triggered by stress, fever, or exercise.Patients may experience palpitations, a sensation of a racing heart, dizziness, and chest discomfort.Causes and Risk Factors: Common causes include physical exertion, emotional...
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...
ECG Interpretation of Arrhythmias I: Sinus Arrhythmias01:16

ECG Interpretation of Arrhythmias I: Sinus Arrhythmias

Arrhythmias are disturbances in the heart's rhythm that lead to abnormal heartbeats. These irregularities can originate from different parts of the heart and are classified based on their origin and nature.
Types of Arrhythmias
Sinus Node Arrhythmias
Sinus Bradycardia: Originating from the sinoatrial (SA) node, sinus bradycardia involves slower impulses, resulting in a heart rate of less than 60 beats per minute (bpm). Causes include sleep, vagal stimulation, beta-blockers, hypothyroidism, and...

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Related Experiment Video

Updated: May 22, 2026

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
10:17

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System

Published on: April 11, 2025

Narrow-Complex Tachycardia With Intermittent Irregularity and Variable QRS Morphology.

Juan Mundisugih1, Rajiv Mahajan2

  • 1Department of Cardiology, Westmead Hospital, Westmead, New South Wales, Australia; Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.

JACC. Case Reports
|May 21, 2026
PubMed
Summary
This summary is machine-generated.

Serial electrocardiogram analysis, focusing on QRS morphology changes, is crucial for diagnosing complex arrhythmias. This method aids in understanding underlying mechanisms beyond simple pattern recognition for accurate patient management.

Keywords:
atrial fibrillationnarrow-complexventricular tachycardia

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Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
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Analyzing Long-Term Electrocardiography Recordings to Detect Arrhythmias in Mice
06:07

Analyzing Long-Term Electrocardiography Recordings to Detect Arrhythmias in Mice

Published on: May 23, 2021

Area of Science:

  • Cardiology
  • Electrophysiology

Background:

  • Arrhythmias pose diagnostic challenges, often requiring advanced interpretation of electrocardiogram (ECG) data.
  • Complex tachyarrhythmias can present with variable regularity and QRS morphology, complicating diagnosis.

Purpose of the Study:

  • To highlight the diagnostic utility of serial ECG analysis in complex tachyarrhythmia cases.
  • To emphasize the importance of detailed QRS morphology assessment for elucidating arrhythmia mechanisms.

Main Methods:

  • Case presentation of an 83-year-old patient with palpitations.
  • Serial electrocardiogram (ECG) monitoring and analysis.
  • Detailed assessment of QRS morphology variations during tachycardia.

Main Results:

  • Serial ECGs revealed narrow-complex tachycardia with changing QRS morphology and regularity.
  • Morphological analysis provided insights into the underlying mechanisms of the complex arrhythmia.

Conclusions:

  • Serial ECG analysis, especially tracking QRS morphology, offers critical diagnostic information.
  • Detailed morphological evaluation aids in precise identification and management of complex arrhythmias.
  • This approach moves beyond basic pattern recognition to uncover specific arrhythmia mechanisms.