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High‐Resolution Fluorescent Imaging Does Not Reveal a Distinct Atrioventricular Nodal Anterior Input Channel (Fast Pathway) in the Rabbit Heart During Sinus Rhythm
Author(s) -
EFIMOV IGOR R.,
FAHY GERARD J.,
CHENG YUANNA,
WAGONER DAVID R.,
TCHOU PATRICK J.,
MAZGALEV TODOR N.
Publication year - 1997
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1997.tb00792.x
Subject(s) - crista terminalis , medicine , interatrial septum , nodal , anatomy , sinus rhythm , atrioventricular node , reentry , optical mapping , sinoatrial node , cardiology , atrial fibrillation , tachycardia , heart rate , left atrium , catheter ablation , blood pressure
Fluorescent Imaging of AVN. Introduction: We sought to determine the precise pathways of engagement of the AV node during sinus rhythm. Methods and Results: Langendorff‐perfused rabbit hearts were stained with 20 μM of the voltage‐sensitive dye di‐4‐ANEPPS. Preparations containing the right atrium, sinoatrial (SA) and AV nodes, and interatrial septum were subsequently dissected and mapped in vitro using a 16 × 16 photodiode array with an adjustable resolution of 150 to 750 μm per diode. Motion artifacts were eliminated by using 15 mM 2,3‐butanedione monoxime (BDM). Activation time‐points were defined as (‐dF/dt) max , where F = fluorescence. Isochronal maps of activation were plotted using the triangulation method. In all preparations, spontaneous activation began at the SA node, rapidly spread along the crista terminalis (CrT), entered the AV nodal region via the posterior “slow” pathway, and retrogradely spread to the septal region with a smaller conduction velocity compared to that along the CrT. Collision of anterograde and retrograde wavefronts was frequently observed in the mid‐septum. Notably, there was no evidence for the presence of a distinct anterior entrance into the AV node. Conclusion: Fast pathway conduction during sinus rhythm results from a broad posterior wavefront that envelops the AV node with subsequent retrograde atrial septal activation.