Personalized Models of Human Atrial Electrophysiology Derived From Endocardial Electrograms

Objective
: Computational models represent a novel framework for understanding the mechanisms behind atrial fibrillation (AF) and offer a pathway for personalizing and optimizing treatment. The characterization of local electrophysiological properties across the atria during procedures remains a challenge. The aim of this work is to characterize the regional properties of the human atrium from multielectrode catheter measurements.
Methods
: We propose a novel method that characterizes regional electrophysiology properties by fitting parameters of an ionic model to conduction velocity and effective refractory period restitution curves obtained by a
$s_\text{1}\_ s_\text{2}$
pacing protocol applied through a multielectrode catheter. Using an in-silico dataset we demonstrate that the fitting method can constrain parameters with a mean error of
$21.9\pm 16.1\%$
and can replicate conduction velocity and effective refractory curves not used in the original fitting with a relative error of
$4.4\pm 6.9\%$
.
Results
: We demonstrate this parameter estimation approach on five clinical datasets recorded from AF patients. Recordings and parametrization took approx. 5 and 6 min, respectively. Models fitted restitution curves with an error of
$\sim 5\%$
and identify a unique parameter set. Tissue properties were predicted using a two-dimensional atrial tissue sheet model. Spiral wave stability in each case was predicted using tissue simulations, identifying distinct stable (2/5), meandering and breaking up (2/5), and unstable self-terminating (1/5) spiral tip patterns for different cases.
Conclusion and significance
: We have developed and demonstrated a robust and rapid approach for personalizing local ionic models from a clinically tractable protocol to characterize cellular properties and predict tissue electrophysiological function.