Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Electrophysiology of Normal Cardiac Rhythm

Electrophysiology of Normal Cardiac Rhythm

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...

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.

Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers

Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers

Class IV antiarrhythmic drugs, such as verapamil and diltiazem, block calcium channels. They primarily affect the heart, slowing the conduction in calcium-dependent tissues like the SA and AV nodes. These drugs manage reentrant supraventricular tachycardia (SVT) and reduce ventricular rate in atrial flutter/fibrillation.
Verapamil, a calcium channel blocker, inhibits calcium movement across myocardial cell membranes and vascular smooth muscle. This results in the dilation of coronary and...

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...

Cardiac Action Potential

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 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...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Cardiovascular prevention: lifestyle and statins--competitors or companions?

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde·2014

Same author

Sodium glucose co-transporter 2 (SGLT2) inhibitors: new among antidiabetic drugs.

Cardiovascular drugs and therapy·2014

Same author

Hypertension, platelets, and inflammatory responses.

Cardiovascular drugs and therapy·2014

Same author

The effect of left ventricular remodelling on soluble ST2 in a cohort of hypertensive subjects.

Journal of human hypertension·2014

Same author

Aspirin in the prevention of cancer.

Lancet (London, England)·2011

Same author

Hypertension, the changing pattern of drug usage.

Cardiovascular journal of Africa·2009

Search research articles

Related Experiment Video

Updated: Jul 8, 2026

Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes

Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes

Published on: March 12, 2013

Cellular mechanism for ischemic ventricular arrhythmias.

L H Opie¹, W T Clusin

¹Medical Research Council/University of Cape Town Ischemic Heart Disease Research Unit, University of Cape Town Medical School, South Africa.

Annual Review of Medicine

|January 1, 1990

Summary

Early ischemia causes ionic shifts, including potassium loss and increased cytosolic calcium. These changes significantly increase the risk of developing cardiac arrhythmias.

More Related Videos

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

A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts

A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts

Published on: February 17, 2023

Related Experiment Videos

Last Updated: Jul 8, 2026

Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes

Isolation and Kv Channel Recordings in Murine Atrial and Ventricular Cardiomyocytes

Published on: March 12, 2013

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

A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts

A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts

Published on: February 17, 2023

Area of Science:

Cardiovascular Physiology
Cellular Electrophysiology

Background:

Ischemia, a condition of reduced blood flow, triggers significant cellular changes.
Ionic homeostasis is critical for normal cardiac function.

Purpose of the Study:

To elucidate the role of specific ionic abnormalities in early ischemia.
To understand the predisposition to arrhythmias caused by these ionic shifts.

Main Methods:

Analysis of ionic concentrations in cellular and extracellular environments during ischemic events.
Correlation of observed ionic changes with the onset of cardiac arrhythmias.

Main Results:

Identified significant extracellular potassium increase and cytosolic calcium rise as key early events in ischemia.
Demonstrated a strong link between these ionic abnormalities and the development of arrhythmias.

Conclusions:

Early ionic derangements, specifically potassium and calcium fluxes, are critical factors in ischemia-induced arrhythmias.
Understanding these ionic mechanisms is vital for developing targeted antiarrhythmic strategies.