A biatrial digital twin integrating electrophysiology, mechanics, and circulation: from physiology to atrial fibrillation

Pico-Cabiro, S.; Zingaro, A.; Puche-Garcia, V.; Lialios, D.; Vazquez, M.; Echebarria-Dominguez, B.; Izquierdo, M.; Carreras-Costa, F.; Saiz, J.; Casoni, E.

doi:10.64898/2026.03.12.711092

bioRxiv · 10.64898/2026.03.12.711092

A biatrial digital twin integrating electrophysiology, mechanics, and circulation: from physiology to atrial fibrillation

Pico-Cabiro, S.·Zingaro, A.·Puche-Garcia, V.·Lialios, D.·Vazquez, M.·Echebarria-Dominguez, B.·Izquierdo, M.·Carreras-Costa, F.·Saiz, J.·Casoni, E.

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Abstract

Atrial electromechanics plays a key role in cardiac function by regulating ventricular filling and global hemodynamics, yet remains challenging to model consistently across scales. In this work, a multiscale atrial digital twin for simulations of normal and pathological atrial function is presented, formulated as an electromechanical framework for biatrial simulations that couples three-dimensional atrial electrophysiology and mechanics with a closed-loop zero-dimensional circulatory model. The framework is calibrated on a patient-specific biatrial anatomy to reproduce physiological regional activation times, atrial volumes, ejection fractions, and pressure-volume loop characteristics. The simulations capture all atrial functional phases throughout the cardiac cycle, including realistic figure-eight pressure-volume loops, an aspect hard to achieve in computational studies. A systematic sensitivity analysis quantifies the influence of active contraction, passive stiffness, boundary conditions, and circulatory parameters on atrial function. Finally, application to a pathological scenario through induced persistent atrial fibrillation demonstrates how electrophysiological remodelling propagates across scales, leading to loss of effective atrial contraction, altered atrioventricular flow patterns, and a clinically relevant reduction in cardiac output. Overall, this multiphysics and multiscale framework provides a robust platform to investigate how atrial electrical alterations drive mechanical and hemodynamic alterations in both healthy and pathological conditions.

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Pico-Cabiro, S., Zingaro, A., Puche-Garcia, V., Lialios, D., Vazquez, M., Echebarria-Dominguez, B., Izquierdo, M., Carreras-Costa, F., Saiz, J., Casoni, E.. 2026-03-16. A biatrial digital twin integrating electrophysiology, mechanics, and circulation: from physiology to atrial fibrillation. https://doi.org/10.64898/2026.03.12.711092

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