The degree of atrial fibrillation (AF)-induced electrical remodeling is usually fixed to a population value in patient-specific atrial models, and in this work we proposed the dominant frequency (DF) as an observable to personalize it.
The Courtemanche-Ramirez-Nattel model was remodeled at five levels (0 to 100% of the reference reduction of Ito, ICaL and IKur), over which the wavelength shortened by 13%. Rotors were induced in a 2D sheet for each level combined with 0, 15, 35 and 45% diffuse fibrosis, and in a personalized left atrial model, at three remodeling degrees, three fibrosis configurations and three global conductivities.
In 2D, DF rose from 4.71 to 5.59 Hz between 0 and 50% remodeling at 15% fibrosis and then saturated, whereas raising fibrosis to 35% lowered it by 2.3–3.1 Hz and abolished its dependence on remodeling. In the patient model, doubling the remodeling shifted DF by up to 0.34 Hz, one fibrosis level by up to 0.47 Hz in the opposite direction, and a ±20% change of the global conductivity by up to 0.55 Hz without a consistent sign. Reentry sustainability depended far more sharply on the remodeling-fibrosis combination.
DF is therefore governed by the structural substrate and by modeling assumptions more than by electrical remodeling.