title: Computer three-dimensional anatomical reconstruction of the human sinus node and a novel paranodal area.
abstract: We have previously shown in rabbit that the pacemaker of the heart (the sinus node) is widespread and matches the wide distribution of the leading pacemaker site within the right atrium. There is, however, uncertainty about the precise location of the pacemaker in human heart, and its spatial relationships with the surrounding right atrial muscle. Therefore, the aim of the current study was to investigate the distribution of the sinus node tissue in a series of healthy human hearts and, for one of the hearts to construct a computer three-dimensional anatomical model of the sinus node, including the likely orientation of myocytes. A combination of experimental techniques--diffusion tensor magnetic resonance imaging (DT-MRI), histology, immunohistochemistry, image processing and computer modelling--was used. Our data show that the sinus node was larger than in previous studies and, most importantly, we identified a previously unknown area running alongside the sinus node (the "paranodal area"), which is even more extensive than the sinus node. This area possesses properties of both nodal and atrial tissues and may have a role in pacemaking. For example, it could explain the wide spread distribution of the leading pacemaker site in human right atrium, a phenomenon known as the wandering pacemaker observed in clinics. In summary, a novel 3D anatomical reconstruction presents a new picture of the distribution of nodal cells within the human right atrium.
authors.affiliation: Cardiovascular Medicine, University of Manchester, Manchester, UK.
authors.forename: Natalie
authors.initials: N
authors.lastname: Chandler
authors.forename: Oleg
authors.initials: O
authors.lastname: Aslanidi
authors.forename: David
authors.initials: D
authors.lastname: Buckley
authors.forename: Shin
authors.initials: S
authors.lastname: Inada
authors.forename: Steven
authors.initials: S
authors.lastname: Birchall
authors.forename: Andrew
authors.initials: A
authors.lastname: Atkinson
authors.forename: Danielle
authors.initials: D
authors.lastname: Kirk
authors.forename: Oliver
authors.initials: O
authors.lastname: Monfredi
authors.forename: Peter
authors.initials: P
authors.lastname: Molenaar
authors.forename: Robert
authors.initials: R
authors.lastname: Anderson
authors.forename: Vinod
authors.initials: V
authors.lastname: Sharma
authors.forename: Daniel
authors.initials: D
authors.lastname: Sigg
authors.forename: Henggui
authors.initials: H
authors.lastname: Zhang
authors.forename: Mark
authors.initials: M
authors.lastname: Boyett
authors.forename: Halina
authors.initials: H
authors.lastname: Dobrzynski
mesh_terms: D000818:Animals; D056324:Diffusion Tensor Imaging / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D051379:Mice; D008953:Models, Anatomic; D032383:Myocytes, Cardiac / Q000166:cytology; D011817:Rabbits; D051381:Rats; D012849:Sinoatrial Node / Q000033:anatomy & histology*