Related Experiment Video
Updated: Jul 16, 2026
07:56
A Model of Long-Term Ventricular Fibrillation in Isolated Rat Hearts
Published on: February 17, 2023
Autonomic nerve stimulation reverses ventricular repolarization sequence in rabbit hearts
Rajkumar Mantravadi1, Bethann Gabris, Tong Liu
1Department of Cardiovascular Sciences, Cardiology Group, University of Leicester, UK.
Circulation Research
|March 17, 2007
Summary
Autonomic nerve stimulation, like sympathetic nerve stimulation, can reverse the direction of repolarization in the heart, potentially influencing arrhythmia vulnerability. This effect is reversible and linked to regional differences in nerve supply.
Area of Science:
- Cardiovascular Physiology
- Autonomic Nervous System Function
- Cardiac Electrophysiology
Background:
- Dispersion of repolarization (DOR) is linked to arrhythmia vulnerability.
- Autonomic nerve activity influences cardiac function.
- Direct measurement of autonomic effects on DOR is lacking.
Purpose of the Study:
- To investigate the direct effects of autonomic nerve stimulation on spatial dispersion of repolarization (DOR).
- To measure changes in apex-base DOR in rabbit hearts.
- To compare autonomic stimulation with pharmacological agents.
Main Methods:
- Langendorff-perfused rabbit hearts with intact innervation.
- Optical mapping to measure action potential durations and DOR.
- Bilateral sympathetic nerve stimulation (SNS) and vagus nerve stimulation.
Main Results:
- SNS increased DOR by 29% and reversed repolarization direction from apex-to-base to base-to-apex.
- Vagus nerve stimulation also reversed DOR direction, particularly when bilateral.
- Isoproterenol and acetylcholine increased DOR but did not alter repolarization direction.
Conclusions:
- Autonomic activity (SNS and vagus nerve stimulation) causes reversible shifts in apex-base DOR.
- Spatial heterogeneities in autonomic effects suggest greater basal than apical innervation.
- These findings provide direct evidence linking autonomic control to DOR and potential arrhythmia mechanisms.
Related Concept Videos
01:19Electrophysiology 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...
01:30Cardiac 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
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
01:28Mechanism 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.