  In this study we present a novel computational model for unprecedented
simulations of the whole cardiac electrophysiology. According to the
heterogeneous electrophysiologic properties of the heart, the whole cardiac
geometry is decomposed into a set of coupled conductive media having different
topology and electrical conductivities: (i) a network of slender bundles
comprising a fast conduction atrial network, the AV-node and the ventricular
bundles; (ii) the Purkinje network; and (iii) the atrial and ventricular
myocardium. The propagation of the action potential in these conductive media
is governed by the bidomain/monodomain equations, which are discretized in
space using an in-house finite volume method and coupled to three different
cellular models, the Courtemanche model [1] for the atrial myocytes, the
Stewart model [2] for the Purkinje Network and the ten Tusscher-Panfilov model
[3] for the ventricular myocytes. The developed numerical model correctly
reproduces the cardiac electrophysiology of the whole human heart in healthy
and pathologic conditions and it can be tailored to study and optimize
resynchronization therapies or invasive surgical procedures. Importantly, the
whole solver is GPU-accelerated using CUDA Fortran providing an unprecedented
speedup, thus opening the way for systematic parametric studies and uncertainty
quantification analyses.
