Open AccessCompartmentalized Structure of the Moderator Band Provides a Unique Substrate for Macroreentrant Ventricular Tachycardia
Author(s) -
Richard D. Walton,
Ali Pashaei,
M. Martinez,
Marion Constantin,
Josselin Duchâteau,
Laura Bear,
Caroline Cros,
Caroline Pascarel-Auclerc,
Yun-Bo Guo,
David Benoist,
Virginie Dubes,
Ndeye Rokhaya Faye,
Sébastien Chaigne,
Sébastien Dupuis,
Dominique Détaille,
Line Pourtau,
Philippe Pasdois,
Fabien Brette,
Julien Rogier,
Louis Labrousse,
Mélèze Hocini,
Edward J. Vigmond,
Michel Haı̈ssaguerre,
Olivier Bernus
Publication year - 2018
Publication title -
circulation. arrhythmia and electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.684
H-Index - 102
eISSN - 1941-3149
pISSN - 1941-3084
DOI - 10.1161/circep.117.005913
Subject(s) - endocardium , ventricular tachycardia , medicine , cardiology , gap junction , compartmentalization (fire protection) , chemistry , intracellular , biochemistry , enzyme
Supplemental Digital Content is available in the text. Background Papillary muscles are an important source of ventricular tachycardia (VT). Yet little is known about the role of the right ventricular (RV) endocavity structure, the moderator band (MB). The aim of this study was to determine the characteristics of the MB that may predispose to arrhythmia substrates. Methods Ventricular wedge preparations with intact MBs were studied from humans (n=2) and sheep (n=15; 40–50 kg). RV endocardium was optically mapped, and electrical recordings were measured along the MB and septum. S1S2 pacing of the RV free wall, MB, or combined S1-RV S2-MB sites were assessed. Human (n=2) and sheep (n=4) MB tissue constituents were assessed histologically. Results The MB structure was remarkably organized as 2 excitable, yet uncoupled compartments of myocardium and Purkinje. In humans, action potential duration heterogeneity between MB and RV myocardium was found (324.6±12.0 versus 364.0±8.4 ms; P <0.0001). S1S2-MB pacing induced unidirectional propagation via MB myocardium, permitting sustained macroreentrant VT. In sheep, the incidence of VT for RV, MB, and S1-RV S2-MB pacing was 1.3%, 5.1%, and 10.3%. Severing the MB led to VT termination, confirming a primary arrhythmic role. Inducible preparations had shorter action potential duration in the MB than RV (259.3±45.2 versus 300.7±38.5 ms; P <0.05), whereas noninducible preparations showed no difference (312.0±30.3 versus 310.0±24.6 ms, respectively). Conclusions The MB presents anatomic and electrical compartmentalization between myocardium and Purkinje fibers, providing a substrate for macroreentry. The vulnerability to sustain VT via this mechanism is dependent on MB structure and action potential duration gradients between the RV free wall and MB.