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Concealed conduction and dual pathway physiology of the atrioventricular node
Shaowen Liu1, S Bertil Olsson, Yanzong Yang
1Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China.
Journal of Cardiovascular Electrophysiology
|March 19, 2004
Summary
Concealed conduction in the atrioventricular (AV) node prevents slow pathway conduction, even with dual pathway physiology. This interaction impacts AV nodal refractory periods and conduction curves in patients with AV nodal reentrant tachycardia.
Area of Science:
- Electrophysiology
- Cardiac Arrhythmias
Background:
- Atrioventricular (AV) node concealed conduction and dual pathway physiology are key electrophysiologic features.
- The interplay between AV nodal concealment and duality remains incompletely understood.
Purpose of the Study:
- To investigate the interaction between AV nodal concealed conduction and dual pathway physiology.
- To elucidate the impact of concealed beats on AV nodal conduction properties.
Main Methods:
- Prospective study of AV conduction curves during premature atrial stimulation in 20 patients with AV nodal reentrant tachycardia and 14 controls.
- Conduction properties were assessed with and without a conditioning blocked impulse, before and after slow pathway ablation.
Main Results:
- AV nodal duality was present in 95% of patients without a blocked impulse but only 10% with a blocked impulse (P < 0.0001).
- Blocked impulses significantly prolonged AV nodal refractory periods and shortened the maximum AH interval (AHmax).
- Slow pathway ablation reduced AHmax in the absence of a blocked impulse, but not with a blocked impulse.
Conclusions:
- Data demonstrate an interaction between AV nodal concealed conduction and dual pathway physiology.
- Concealed beats effectively prevented slow pathway conduction in the AV node for both patients with and without AV nodal reentry.