Related Experiment Video
Updated: Aug 21, 2026
Electrophysiological Investigations of Retinogeniculate and Corticogeniculate Synapse Function
Published on: August 7, 2019
Electrophysiological characteristics of accessory pathways with prolonged retrograde conduction
Kuo-Hung Lin1, Chi-Tai Kuo, Nazar Luqman
1Department of Cardiology, Chang Gung University and Chang Gung Memorial Hospital, Linkou, Taiwan.
Abstract:
Electrophysiological characteristics of an accessory pathway (AP) with a long ventriculoatrial (VA) interval (arbitrarily defined as > or = 50 ms and absence of continuous electrical activity) and no retrograde decremental property are described in this study. Fifteen patients (group 1) were compared with 171 patients with normal VA conduction (group 2). Mean VA conduction time was 77 +/- 24 versus 34 +/- 12 ms in group 1 versus group 2, respectively. Group 1 patients were older (55 +/- 14 vs 40 +/- 14 years), the male to female ratio was higher (2.8 vs 1.6), and APs were more prevalent on the right (60%) but manifest APs were lower (20% vs 54%) compared to group 2 patients (P < 0.05 in all cases). QRS morphology during induced atrioventricular reciprocating tachycardia was identical in both groups but the tachycardia cycle length was longer in group 1 (373 +/- 29 vs 344 +/- 50 ms, P < 0.05). Retrograde AP block cycle length and effective refractory period were greater in group 1 (362 +/- 59 vs 293 +/- 57 ms; 330 +/- 58 vs 273 +/- 55 ms, both P < 0.05). Adenosine (up to 18 mg) and verapamil (5-10 mg) failed to block the VA conduction via AP during ventricular pacing. In group 1 the number of radiofrequency lesions for a successful ablation were significantly less (3 +/- 2 vs 6 +/- 5, P < 0.05). In conclusion, APs with a long VA interval and no decremental retrograde conduction have electrophysiological characteristics that are different from those with a short VA interval. Role of aging deserves further exploration.
More Related Videos
08:05Optimization of Transesophageal Atrial Pacing to Assess Atrial Fibrillation Susceptibility in Mice
Published on: June 29, 2022
09:34Use of In Vivo Single-fiber Recording and Intact Dorsal Root Ganglion with Attached Sciatic Nerve to Examine the Mechanism of Conduction Failure
Published on: August 27, 2019
Related Concept Videos
01:30Cardiac Action Potential
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
01:19Electrophysiology of Normal Cardiac Rhythm
01:28Action Potential: Phases of Stimulation
Resting Phase:
In this phase, the cell's membrane is at its resting potential, typically around -70 millivolts (mV) for neurons. Inside the cell, there is a higher concentration of potassium ions (K+) and a lower concentration of sodium ions (Na+). Voltage-gated sodium channels are closed, and...
01:19Conduction System of the Heart
The pacemaker cells are located in two primary nodes: the sinoatrial (SA) node and the atrioventricular (AV) node. The SA node pacemaker cells can autonomously depolarize, triggering an action potential that leads to the...
01:20Conduction System of the Heart
This system relies on the unique properties of nodal and Purkinje cells:...
01:23Propagation of Action Potentials
Neurons (nerve cells) have a resting membrane potential, with a slightly negative charge inside compared to outside. This is maintained by ion channels, such as sodium (Na+) and potassium (K+) channels, which control the flow of ions. When a stimulus, like a touch or a signal from another neuron, triggers the neuron, sodium channels open, allowing sodium ions to...