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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...

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...

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...

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.

Mechanism of Cardiac Arrhythmias

Mechanism of Cardiac Arrhythmias

Arrhythmias are irregular heart rhythms occurring when the heart's electrical impulses become abnormal. These disturbances can lead to various symptoms, depending on their severity and the underlying cause. Some common factors contributing to arrhythmias include hypoxia, ischemia, electrolyte imbalances, excessive catecholamine exposure, drug toxicity, and muscle overstretching. Arrhythmias can be classified into two main types based on the rate and site of origin of abnormal heart rhythms.

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...

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Related Experiment Video

Updated: Jun 21, 2026

Optimization of Transesophageal Atrial Pacing to Assess Atrial Fibrillation Susceptibility in Mice

Optimization of Transesophageal Atrial Pacing to Assess Atrial Fibrillation Susceptibility in Mice

Published on: June 29, 2022

Paroxysmal atrioventricular block.

Sinjin Lee¹, Hein J J Wellens, Mark E Josephson

¹Department of Cardiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA. ghinii@yahoo.com

|July 28, 2009

Summary

This summary is machine-generated.

Paroxysmal atrioventricular block (AVB) is a dangerous condition causing syncope and sudden cardiac death. Diagnosis is often missed due to its unpredictable nature and lack of clear evidence during normal heart rhythms.

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Robotic Ablation of Atrial Fibrillation

Robotic Ablation of Atrial Fibrillation

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Last Updated: Jun 21, 2026

Optimization of Transesophageal Atrial Pacing to Assess Atrial Fibrillation Susceptibility in Mice

Optimization of Transesophageal Atrial Pacing to Assess Atrial Fibrillation Susceptibility in Mice

Published on: June 29, 2022

Robotic Ablation of Atrial Fibrillation

Robotic Ablation of Atrial Fibrillation

Published on: May 29, 2015

Area of Science:

Cardiology
Electrophysiology

Background:

Paroxysmal atrioventricular block (AVB) is a critical condition characterized by sudden transitions from 1:1 conduction to complete heart block.
This entity poses a significant risk of syncope and sudden cardiac death due to an unreliable escape mechanism.

Purpose of the Study:

To highlight the diagnostic challenges associated with paroxysmal AVB.
To emphasize the importance of recognizing this condition despite its elusive presentation.

Main Methods:

Review of clinical presentations and diagnostic criteria for paroxysmal AVB.
Analysis of factors contributing to missed or delayed diagnoses.

Main Results:

Paroxysmal AVB is frequently overlooked due to its unpredictable episodes.
Lack of persistent electrocardiographic abnormalities during normal conduction complicates diagnosis.
Unfamiliarity and unpredictability are key barriers to timely identification.

Conclusions:

Paroxysmal AVB requires heightened clinical awareness for accurate diagnosis.
Improved recognition protocols are needed to prevent adverse outcomes associated with this condition.