Related Experiment Video
Updated: Aug 2, 2026
Remote Magnetic Navigation for Accurate, Real-time Catheter Positioning and Ablation in Cardiac Electrophysiology Procedures
Published on: April 21, 2013
Demonstration of phase-3 and phase-4 retrograde block in a second concealed accessory pathway after an initial
K Azegami1, F Suzuki, M Kurabayashi
1Department of Allied Health Sciences, Tokyo Medical and Dental University School of Medicine, Japan.
Abstract:
We report a patient with concealed Wolff-Parkinson-White syndrome who, following catheter ablation, demonstrated phase-3 and phase-4 retrograde block in a concealed accessory pathway. After an initial 'apparently successful' ablation, retrograde conduction was through the atrioventricular node during constant ventricular pacing. Ventricular extrastimulus testing was performed at a basic drive cycle length of 600 ms. Unexpectedly, ventricular extrastimuli at coupling intervals of 440-380 ms were conducted retrogradely over an accessory pathway, consistent with a phase-3 and phase-4 retrograde block in the accessory pathway. Residual accessory pathway conduction was eliminated in a single ablation session.
