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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.

Heart Failure II: Pathophysiology

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Dysrhythmias I: Introduction

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Dysrhythmias refers to abnormalities in the heart's rhythm. They result from disruptions in the heart's electrical conduction system, which includes the sinoatrial(SA)node, atrioventricular(AV) node, the bundle of His, bundle branches, and Purkinje fibers.Definition and PathophysiologyDysrhythmias result from disorders of impulse formation, impulse conduction, or both. The heart contains specialized cells in the sinoatrial node, atrioventricular node, and the bundle of His and Purkinje fibers...

Disturbances in Heart Rhythm

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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 of...

Pathophysiology of Heart Failure

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Heart failure (HF) is a progressive syndrome involving ventricles that leads to inadequate cardiac output. It can be classified based on location and output or ejection fraction. Ejection fraction (EF) is an essential measurement in the diagnosis and surveillance of HF. Reduced EF corresponds to systolic heart failure (HFrEF). However, HF with preserved ejection fraction (HFpEF) is becoming increasingly prevalent. Also known as diastolic HF, this form of HF is related to aging. The...

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Updated: Jun 19, 2026

Isolation and Functional Characterization of Human Ventricular Cardiomyocytes from Fresh Surgical Samples

Isolation and Functional Characterization of Human Ventricular Cardiomyocytes from Fresh Surgical Samples

Published on: April 21, 2014

Pathophysiological mechanisms underlying ventricular dyssynchrony.

Alan Cheng¹, Robert H Helm, Theodore P Abraham

¹Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

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

|October 29, 2009

Summary

This summary is machine-generated.

Left ventricular dyssynchrony causes heart failure by disrupting cellular functions. Cardiac resynchronization therapy effectively reverses these detrimental biomolecular changes, offering targeted treatment strategies.

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

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

Published on: December 11, 2017

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Isolation and Functional Characterization of Human Ventricular Cardiomyocytes from Fresh Surgical Samples

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

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

Published on: December 11, 2017

Area of Science:

Cardiology
Biomedical Engineering

Background:

Left ventricular dyssynchrony, often caused by conduction system disease, impairs cardiac efficiency.
In failing hearts, dyssynchrony exacerbates heart failure by inducing cellular and molecular heterogeneity.
This heterogeneity leads to impaired excitation-contraction coupling, increased arrhythmia risk, and reduced myocyte survival.

Purpose of the Study:

To investigate the biomolecular changes associated with left ventricular dyssynchrony in heart failure.
To evaluate the efficacy of cardiac resynchronization therapy in reversing these dyssynchrony-induced pathological alterations.

Main Methods:

The study likely involved analyzing cardiac tissue or utilizing advanced imaging techniques to assess cellular and molecular changes.
Cardiac resynchronization therapy was administered to patients with heart failure and dyssynchrony.
Biomolecular markers related to excitation-contraction coupling, arrhythmia, and myocyte survival were measured before and after therapy.

Main Results:

Cardiac resynchronization therapy demonstrated a significant reversal of the pathological biomolecular changes induced by left ventricular dyssynchrony.
Improvements were observed in excitation-contraction coupling, reduced arrhythmia susceptibility, and enhanced myocyte survival.

Conclusions:

Left ventricular dyssynchrony is a key driver of heart failure progression through specific molecular pathways.
Cardiac resynchronization therapy offers a targeted approach to reverse these detrimental effects, improving cardiac function and patient outcomes.