Related Experiment Video
Updated: Jul 18, 2026
08:24
The Joint Effect of Social Comparison and Social Distance on Evaluation of Intertemporal Choice Outcomes in Event-related Potential Studies
Published on: August 25, 2023
A comparative analysis of antegrade and retrograde conduction patterns in man
Circulation
|November 1, 1975
Summary
Antegrade conduction is typically better than retrograde conduction in the atrioventricular (A-V) node and His-Purkinje system. Predicting refractory periods during premature stimulation is challenging and cannot be reliably extrapolated from incremental pacing results.
Area of Science:
- Electrophysiology
- Cardiac conduction studies
Background:
- Understanding atrioventricular (A-V) nodal and His-Purkinje system (HPS) conduction is crucial for diagnosing cardiac arrhythmias.
- Antegrade and retrograde conduction pathways can exhibit different electrophysiological properties.
Purpose of the Study:
- To compare antegrade and retrograde conduction patterns and refractory periods in the A-V node and HPS.
- To investigate the predictability of refractoriness during premature stimulation based on incremental pacing.
Main Methods:
- His bundle electrogram recordings were utilized.
- Incremental atrial and ventricular pacing were performed.
- The extrastimulus technique was employed to assess refractory periods.
Main Results:
- Antegrade conduction was superior to retrograde conduction in 50/36 patients, often due to slower retrograde Wenckebach or absent ventriculo-atrial conduction.
- Retrograde block was frequently localized to the A-V node.
- Refractory period sites (A-V node, HPS, atrial/ventricular muscle) varied and could not always be predicted from incremental pacing.
Conclusions:
- Antegrade conduction generally surpasses retrograde conduction in the A-V node and HPS.
- Predicting the area of maximum refractoriness during premature stimulation is difficult and cannot be reliably extrapolated from incremental pacing.
- Extrapolating retrograde conduction and refractory period patterns from antegrade studies is equally challenging.
More Related Videos
Related Concept Videos
02:31Synteny and Evolution
John H. Renwick first coined the term “synteny” in 1971, which refers to the genes present on the same chromosomes, even if they are not genetically linked. The species with common ancestry tend to show conserved syntenic regions. Therefore, the concept of synteny is nowadays used to describe the evolutionary relationship between species.
Around 80 million years ago, the human and mice lineages diverged from the common ancestor. During the course of evolution, the ancestral chromosome underwent...
Around 80 million years ago, the human and mice lineages diverged from the common ancestor. During the course of evolution, the ancestral chromosome underwent...
01:24Comparison Between Electrical And Gravitational Forces
There are four fundamental forces in nature: the gravitational force, the electromagnetic force, the strong nuclear force, and the weak nuclear force. To compare the numerical strengths of the first two, take two particles of the same kind. Since electrons are fundamental particles, they are a good example.
Since both are inverse square law forces, the distance gets canceled when the ratio of the two forces is considered. Instead, the ratio of the electrical and gravitational forces depends on...
Since both are inverse square law forces, the distance gets canceled when the ratio of the two forces is considered. Instead, the ratio of the electrical and gravitational forces depends on...
01:24Comparison between RL and RC circuits
An RC circuit consists of resistance and capacitance, while in an RL circuit, capacitance is replaced by an inductor. RL and RC circuits are first-order differential circuits that store energy. An RC circuit stores energy in the electric field, while an RL circuit stores energy in the magnetic field. When connected to a battery, an RC circuit charges the capacitor, causing the current to decrease from maximum to zero upon being fully charged. This increases the voltage across the capacitor from...
01:18Hierarchy of Motor Control
The hierarchy of motor control refers to the different levels of organization and processing involved in controlling movement in the body. These levels range from higher cortical areas involved in planning and decision-making to lower spinal cord reflexes that respond automatically to external stimuli.
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
01:26Per-Unit Sequence Models
An ideal Y-Y transformer, grounded through neutral impedances, displays per-unit sequence networks akin to those of a single-phase ideal transformer when subjected to balanced positive- or negative-sequence currents. These currents do not produce neutral currents, and their associated voltage drops.
Zero-sequence currents, which are identical in magnitude and phase, generate a neutral current, resulting in voltage drops across the neutral impedance and the low-voltage winding. If the...
Zero-sequence currents, which are identical in magnitude and phase, generate a neutral current, resulting in voltage drops across the neutral impedance and the low-voltage winding. If the...