Study of cardiac pacemaker excitation using generic ionic models and realistic cell distribution.
Generic ionic models optimized to replicate experimentally recorded cardiac action potentials (APs) from the central and peripheral sinoatrial node (SAN), the natural pacemaker of the heart, as well as atrial intact-myocytes are implemented in a realistic 2D model of rabbit SAN geometry. The model was used to investigate two frequently-proposed modes of SAN architecture: the gradient and mosaic hypotheses. In a simplified gradient arrangement, the peripheral SAN region acts as a transition zone between the central SAN and atrium and is required for spontaneous rhythmic initiation of APs from central SAN into the atria. Furthermore, the application of optimized single cell parameters to the realistic 2D rabbit geometry did not accurately replicate experimentally recorded APs. On the other hand, in an adapted mosaic geometry, peripheral SAN cells were not required to produce spontaneous regular excitation.
Graduate School of Biomedical Engineering, University of New South Wales, Sydney 2052, Australia.
Adrian D
AD
Bradd
Amr
A
Al Abed
Tianruo
T
Guo
Nigel H
NH
Lovell
Socrates
S
Dokos
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D016275:Atrial Function / Q000502:physiology; D001683:Biological Clocks / Q000502:physiology*; D006325:Heart Atria / Q000378:metabolism; D006801:Humans; D007477:Ions / Q000378:metabolism; D008955:Models, Cardiovascular; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D011817:Rabbits; D012849:Sinoatrial Node / Q000166:cytology / Q000502:physiology*
D007477:Ions