Cardiac arrhythmias and Griffiths phase: desynchronization of excitable cells
Résumé
Challenges of C arrhythmias raised by the data:
1-Most frequent cause of embolic stroke (AF),
with evolution to chronic disease. Major cause
of natural death (VF), about 5% only are saved.
2-Hysteresis: strike twice and patient resuscitates.
3-Most models refer to chaotic dynamics, but this
does not describe spontaneous reversions to
lesser C arrhythmias.
Some features suggest intrinsic disorder:
1-The data show intermittency of beat-to-beat
intervals and peaks amplitude.
2-Slow evolution of vulnerability (the
susceptibility), so called remodeling.
Conduction velocity is not known to be very much affected. Intermittency may instead reveal nucleation and contamination processes à la
Pomeau. However, the medium is excitable and excitability is a robust cycle to any homo- or heteroclinic nucleation. Alteration of conduction, e.g. on a nearly percolating fibrotic substrate, yields fancy anatomical reentries, but no such intermittent behavior. We believe that the data is suggestive of fragmented pulses, following from the desynchronization of the network of electrically coupled excitable cells.
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