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Dysrhythmias IV: Characteristics of Bradyarrhythmias

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...

Dysrhythmias III: Characteristics of Dysrhythmias

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.

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

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...

Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers

Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers

Class III antiarrhythmic drugs are a group of medications that can prolong action potentials in the heart. They achieve this by blocking potassium channels or enhancing inward currents from sodium channels. However, these drugs have a unique property of "reverse use-dependence," which is most pronounced at slower heart rates and can lead to torsades de pointes—a specific type of arrhythmia. However, it is essential to note that excessive QT interval prolongation—a measure of the heart's...

Dysrhythmias II: Classification of Tachyarrhythmias

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...

Disturbances in Heart Rhythm

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...

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Related Experiment Video

Updated: Jun 5, 2026

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation

Published on: January 16, 2019

[The long QT syndrome].

C Garweg¹, V D'Orio, P Mélon

¹Service de Cardiologie, CHU de Liège, Belgique.

Revue Medicale De Liege

|December 31, 2010

Summary

This summary is machine-generated.

Congenital long QT syndrome (LQTS) is an inherited heart condition causing dangerous arrhythmias and sudden death. Diagnosis can be challenging, especially in borderline cases.

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Electrocardiogram Recordings in Anesthetized Mice using Lead II

Electrocardiogram Recordings in Anesthetized Mice using Lead II

Published on: June 20, 2020

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Last Updated: Jun 5, 2026

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation

Determining the Likelihood of Variant Pathogenicity Using Amino Acid-level Signal-to-Noise Analysis of Genetic Variation

Published on: January 16, 2019

Electrocardiogram Recordings in Anesthetized Mice using Lead II

Electrocardiogram Recordings in Anesthetized Mice using Lead II

Published on: June 20, 2020

Area of Science:

Cardiology
Genetics
Electrophysiology

Context:

Congenital long QT syndrome (LQTS) is a hereditary cardiac condition.
Characterized by QT interval prolongation (> 440 ms) on ECG.
Associated with high risk of ventricular arrhythmias like torsade de pointe, syncope, and sudden cardiac death.

Purpose:

Discuss the etiology, pathogenesis, diagnosis, and treatment of LQTS.
Highlight diagnostic complexities in borderline cases.
Provide a comprehensive overview of LQTS.

Summary:

LQTS involves genetic mutations in cardiac ion channel subunits or regulatory proteins.
Clinical presentation includes syncope and sudden cardiac death.
Diagnostic challenges exist, particularly in borderline presentations.

Impact:

Improves understanding of LQTS for clinicians and researchers.
Aids in the diagnosis and management of patients with LQTS.
Contributes to the knowledge base for inherited cardiac conditions.