Related Concept Videos
01:15Neurogenesis and Regeneration of Nervous Tissue
In the CNS, neurogenesis, the birth of new neurons from stem cells, is limited to the hippocampus in adults. In other regions of the brain and spinal cord, neurogenesis is almost non-existent due to inhibitory influences from neuroglia, especially oligodendrocytes, and the absence of growth-stimulating cues. The myelin produced by oligodendrocytes in the CNS inhibits neuronal regeneration. Furthermore, astrocytes proliferate rapidly after neuronal damage, forming scar tissue that physically...
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.
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
01:28Dysrhythmias 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...
01:30Introduction Cardiac Emergencies
Cardiac emergencies are critical situations involving the heart that require immediate medical intervention to prevent severe complications or death. These emergencies often arise from underlying heart conditions that impair the heart's ability to function correctly.Types of Cardiac EmergenciesThe most common types of cardiac emergencies include Acute Coronary Syndrome (ACS), myocardial infarction (MI), cardiac arrest, and heart failure.Acute Coronary Syndrome (ACS)Acute Coronary Syndrome (ACS)...
01:25Secondary Spinal Cord Injury llI: Pathophysiology
Early Ischemia and Ionic ImbalanceWithin minutes of spinal cord injury, a secondary cascade begins, progressing over hours to weeks. Vascular damage reduces blood flow, causing ischemia and mitochondrial dysfunction. ATP depletion leads to ion pump failure, membrane depolarization, sodium influx, potassium efflux, and water accumulation, resulting in cellular swelling. Increased intracellular calcium further disrupts mitochondria and accelerates cellular injury.Excitotoxicity and Neuronal...
You might also read
Related Articles
Articles linked to this work by shared authors, journal, and citation graph.
Sort by
Same author
[Transition patterns of frailty states among Chinese aged 50 years and above: a sequence analysis].
Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi·2026
Same author
[Association between lipid levels and the risk of Graves' ophthalmopathy: Mendelian randomization and clinical observational analysis].
[Zhonghua yan ke za zhi] Chinese journal of ophthalmology·2025
Same author
[Stiffness of scleral fibroblasts and extracellular matrix remodeling in models of cellular senescence].
[Zhonghua yan ke za zhi] Chinese journal of ophthalmology·2025
Related Experiment Video
Updated: Jul 9, 2026
06:40
Impact of Intracardiac Neurons on Cardiac Electrophysiology and Arrhythmogenesis in an Ex Vivo Langendorff System
Published on: May 22, 2018
Nerve sprouting and sudden cardiac death.
J M Cao1, L S Chen, B H KenKnight
1Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
Circulation Research
|April 14, 2000
Summary
Sudden cardiac death (SCD) risk increases with sympathetic nerve sprouting after myocardial infarction (MI). Nerve growth factor (NGF) infusion augmented this sprouting, leading to more ventricular arrhythmias and SCD in a canine model.
Area of Science:
- Cardiovascular Research
- Autonomic Nervous System
- Cardiac Electrophysiology
Background:
- Sudden cardiac death (SCD) is a significant concern in patients with chronic myocardial infarction (MI).
- The precise mechanisms linking chronic MI to SCD, particularly the role of the autonomic nervous system, remain incompletely understood.
- Sympathetic nerve regeneration, or sprouting, following cardiac injury is a potential but unconfirmed contributor to arrhythmogenesis.
Purpose of the Study:
- To test the hypothesis that augmented sympathetic nerve sprouting increases the probability of ventricular tachycardia (VT), ventricular fibrillation (VF), and SCD in chronic MI.
- To investigate the effect of nerve growth factor (NGF) on sympathetic nerve sprouting in a canine model of chronic MI.
- To establish a high-yield experimental model for studying VT, VF, and SCD in the context of MI and autonomic dysregulation.
Main Methods:
- A canine model of chronic myocardial infarction (MI) with complete atrioventricular (AV) block was utilized.
- Cardiac sympathetic nerve sprouting was induced by infusing nerve growth factor (NGF) into the left stellate ganglion in the experimental group (n=9).
- Control dogs (n=6) with MI and AV block did not receive NGF infusion; sympathetic sprouting was assessed via immunocytochemical staining.
Main Results:
- Immunocytochemical analysis confirmed significantly greater sympathetic nerve sprouting in the NGF-infused experimental group compared to controls.
- The experimental group exhibited a 10-fold higher frequency of spontaneous phase 2 ventricular tachycardia (VT) compared to the control group (2.0/day vs. 0.2/day).
- Four dogs in the experimental group experienced sudden cardiac death due to spontaneous ventricular fibrillation (VF), while no control dogs died suddenly.
Conclusions:
- Myocardial infarction (MI) leads to sympathetic nerve sprouting, a process that can be augmented by nerve growth factor (NGF) infusion.
- Augmented sympathetic nerve sprouting in dogs with chronic MI and AV block significantly increases the incidence of ventricular tachycardia, ventricular fibrillation, and sudden cardiac death.
- The extent of sympathetic nerve sprouting may be a critical determinant of sudden cardiac death risk in patients with chronic myocardial infarction.