Jove
Visualize
Contáctanos

Videos de Conceptos Relacionados

Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers01:22

Antiarrhythmic Drugs: Class I Agents as Sodium Channel Blockers

Class I antiarrhythmic drugs are used to treat various types of arrhythmias or irregular heart rhythms. These drugs block the sodium (Na+) channels in the cardiac cells, thereby affecting the movement of electrical impulses across the heart. Class I antiarrhythmic drugs are divided into three subgroups: Class IA, Class IB, and Class IC, each with distinct mechanisms of action and effects on the heart.
Class 1A Antiarrhythmic Drugs: These drugs work by moderately blocking sodium channels,...
Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers01:24

Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers

Adrenergic stimulation generally impacts cardiac rate and rhythm. Specifically, stimulation of the β-adrenoceptors triggers an increase in intracellular calcium ion influx and pacemaker currents, which may cause arrhythmias. Catecholamines like adrenaline also demonstrate β2-adrenoceptor-mediated hypokalemia, impacting cardiac action potential and disrupting the normal cardiac rhythm. Class II antiarrhythmic drugs are β-adrenoceptor antagonists or β-blockers, which indirectly block calcium...
Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers01:12

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...
Antiarrhythmic Drugs: Class IV Agents as Calcium Channel Blockers01:20

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...
Heart Failure Drugs: β-Blockers01:22

Heart Failure Drugs: β-Blockers

β-adrenergic antagonists, commonly known as β-blockers, block the effects of sympathetic neurotransmitters such as noradrenaline (NA) and adrenaline (ADR). They have several beneficial effects in heart failure treatment. They reduce heart rate, the force of contraction, and cardiac muscle relaxation. They also slow the atrial-ventricular conduction rate and raise the threshold for arrhythmias. The concentration of β-blockers determines their effects on bronchodilation, vasodilation, and...
Mitral Stenosis I: Introduction01:22

Mitral Stenosis I: Introduction

Mitral Valve Stenosis (MVS) is a heart condition where the mitral valve narrows, impeding blood circulation from the left atrium to the left ventricle. The etiology and pathophysiology of this condition are multifaceted, leading to a cascade of cardiovascular complications.Causes of Mitral Valve StenosisRheumatic Heart Disease: It is the main cause of mitral valve stenosis, particularly in developing nations. This condition arises from rheumatic fever, an inflammatory illness resulting from...

También podría leer

Artículos Relacionados

Artículos vinculados a este trabajo por autores compartidos, revista y gráfico de citas.

Ordenar por
Same author

Mergers and migrations: drivers of population genetic structure in a captive rhesus macaque colony.

BMC genomics·2026
Same author

The genomic legacy of selectively breeding rhesus macaques for HIV/AIDS-related research.

bioRxiv : the preprint server for biology·2025
Same author

Canadian Surgery Forum: Abstracts of presentations to the Annual Meetings of the Canadian Association of Bariatric Physicians and Surgeons, Canadian Association of General Surgeons, Canadian Association of Thoracic Surgeons, Canadian Hepato-Pancreato-Biliary Society, Canadian Society of Surgical Oncology, Canadian Society of Colon and Rectal Surgeons, London, Ont. Sept. 15-18, 2011.

Canadian journal of surgery. Journal canadien de chirurgie·2022
Same author

Postmenopausal women's adherence to pelvic floor muscle exercises over 2 years.

Climacteric : the journal of the International Menopause Society·2021
Same author

Partnering with survivors & families to determine research priorities for adult out-of-hospital cardiac arrest: A James Lind Alliance Priority Setting Partnership.

Resuscitation plus·2021
Same author

Energy Flux Densities near the Electron Dissipation Region in Asymmetric Magnetopause Reconnection.

Physical review letters·2021
Same journal

Eugene Braunwald, MD, 1929-2026.

Circulation·2026
Same journal

AHA/ACC/ESC/WHF Expert Consensus Document: Second Universal Definition of Heart Failure (2026).

Circulation·2026
Same journal

Advancing Quality in the Evaluation, Surveillance, and Management of Aortic Stenosis: A Report From the AHA Target: AS Registry.

Circulation·2026
Same journal

Heart Failure Occurring in the Perinatal Period: A Scientific Statement From the American Heart Association.

Circulation·2026
Same journal

Correction to: 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Dyslipidemia: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.

Circulation·2026
Same journal

Correction to: The Natural History of Massive Left Ventricular Hypertrophy in Pediatric Hypertrophic Cardiomyopathy: A Multiregistry Analysis.

Circulation·2026
Ver todos los artículos relacionados
JoVE
x logofacebook logolinkedin logoyoutube logo
ACERCA DE JoVE
Visión GeneralLiderazgoBlogCentro de Ayuda JoVE
AUTORES
Proceso de PublicaciónConsejo EditorialAlcance y PolíticasRevisión por ParesPreguntas FrecuentesEnviar
BIBLIOTECARIOS
TestimoniosSuscripcionesAccesoRecursosConsejo Asesor de BibliotecasPreguntas Frecuentes
INVESTIGACIÓN
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchivo
EDUCACIÓN
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualCentro de Recursos para ProfesoresSitio de Profesores
Términos y Condiciones de Uso
Política de Privacidad
Políticas

Video Experimental Relacionado

Updated: Jun 23, 2026

Echocardiographic Evaluation of Atrial Communications before Transcatheter Closure
07:41

Echocardiographic Evaluation of Atrial Communications before Transcatheter Closure

Published on: February 8, 2022

Los bloqueadores de unión de brecha disminuyen los umbrales de desfibrilación sin cambios en la refractividad

X Qi1, P Varma, D Newman

  • 1Department of Medicine, St Michael's Hospital, University of Toronto, Toronto, Ont, Canada.

Circulation
|September 26, 2001
PubMed
Resumen
Este resumen es generado por máquina.

Los bloqueadores de unión de brecha como 16-DSA y 1-heptanol disminuyen significativamente el umbral de desfibrilación (DFT) y la dispersión de la longitud del ciclo de fibrilación ventricular (VFCL). En contraste, la lidocaína aumenta la DFT, a pesar de efectos similares en la velocidad de conducción.

Más Videos Relacionados

Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence
10:52

Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence

Published on: December 23, 2022

Bidirectional Electrical and Optoelectronic Interfaces in Healthy and Ischemic Ex Vivo Rat Hearts
08:33

Bidirectional Electrical and Optoelectronic Interfaces in Healthy and Ischemic Ex Vivo Rat Hearts

Published on: July 18, 2025

Videos de Experimentos Relacionados

Last Updated: Jun 23, 2026

Echocardiographic Evaluation of Atrial Communications before Transcatheter Closure
07:41

Echocardiographic Evaluation of Atrial Communications before Transcatheter Closure

Published on: February 8, 2022

Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence
10:52

Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence

Published on: December 23, 2022

Bidirectional Electrical and Optoelectronic Interfaces in Healthy and Ischemic Ex Vivo Rat Hearts
08:33

Bidirectional Electrical and Optoelectronic Interfaces in Healthy and Ischemic Ex Vivo Rat Hearts

Published on: July 18, 2025

Área de la Ciencia:

  • Electrofisiología cardiovascular electrofisiología cardiovascular.
  • Farmacología Farmacología.
  • Física médica La física médica es la física médica.

Sus antecedentes:

  • Las arritmias de reentrada dependen de las propiedades de los tejidos como la refractividad y la velocidad de conducción.
  • El impacto de los bloqueadores de canales Na(+) y K(+) en la electrofisiología y el umbral de desfibrilación (DFT) es conocido, pero los efectos de los bloqueadores de unión de brecha son menos conocidos.

Objetivo del estudio:

  • Investigar los efectos de los bloqueadores de la unión del hueco (ácido 16-doxil-steárico y 1-heptanol) y un bloqueador de los canales de sodio (lidocaína) en el umbral de desfibrilación (DFT) y las propiedades electrofisiológicas en corazones de conejo aislados.

Principales métodos:

  • Las mediciones del umbral de desfibrilación (DFT) se tomaron antes y después de la administración de ácido 16-doxil-steárico (16-DSA), 1-heptanol o lidocaína en corazones de conejo perfundidos aislados.
  • Se evaluaron los parámetros electrofisiológicos, incluida la duración del ciclo de fibrilación ventricular (VFCL), la duración del QRS y el período refractario ventricular efectivo.

Principales resultados:

  • 16-DSA y 1-heptanol disminuyeron significativamente la DFT en un 23% y un 21%, respectivamente. La lidocaína aumentó el DFT en un 26%.
  • Todos los agentes aumentaron la duración de VFCL y QRS, y disminuyeron la dispersión de VFCL. La refractividad no se modificó con los bloqueadores de unión de hueco, pero aumentó con la lidocaína.
  • Los corazones de control no mostraron cambios significativos en el DFT o en las variables electrofisiológicas.

Conclusiones:

  • El desacoplamiento eléctrico a través de 16-DSA y 1-heptanol reduce la dispersión de DFT y VFCL sin afectar la refractividad.
  • La lidocaína, mientras que ralentiza la conducción de manera similar, aumenta la DFT, destacando los efectos diferenciales de los bloqueadores de canales en la estabilidad eléctrica cardíaca.