A Novel Ventricular Digital Twin: Modeling Transmural Scar Heterogeneity and Purkinje–Myocardial Junction

Fuyu Cheng1, Johanna Tonko2, Elisa Rauseo1, Semhar Biniam Misghina1, Carlos Edgar Lopez Barrera1, Masimba Nemaire3, Edward Vigmond4, Gregory Slabaugh1, Nay Aung1, Pier Lambiase5, Steffen E Petersen1, Caroline H Roney1
1Queen Mary University of London, 2University College London, 3IHU Liryc, 4LIRYC - University of Bordeaux, 5UCL


Abstract

Introduction: biventricular digital twins (BDTs) offer promise for preci-sion cardiology, yet most models lack key pathological and anatomical de-tails such as transmural scar heterogeneity and the Purkinje network. Accurate transmurally heterogeneous distribution of scar and Purkinje–myocardial junctions (PMJs) are essential for simulating arrhythmia dynamics. Methods: BDTs were constructed from CMR, EGM, and ECG data, in-corporating fibre orientation, transmurally heterogeneous scar distribution (dense fibrosis and border zone defined by pixel intensity), and electrophysio-logical parameters. PMJs were generated using a novel algorithm based on Purkinje morphology and transmural extent. PMJ conductivity was calibrated by tuning it iteratively so that the simulated local activation time (LAT) at the scar-free calibration point in the basal LV endocardium matched the clini-cal LAT, using the pacing site identified from the clinical LAT map. Accura-cy was validated at additional non-calibrated locations. ventricular tachycardia (VT) induction and re-entry analysis were performed in BDTs. Results: BDTs were constructed for 3 VT patients (2 endocardial and 1 ep-icardial ablation cases). Simulated LATs at 10 structurally representative en-docardial sites showed strong agreement with clinical LATs (within 7.46 ± 3.27 ms). VT was successfully induced in all BDTs. Simulations re-produced reentry circuits that matched clinical ablation locations: reentry was inducible only from pacing sites consistent with the clinical access route (ep-icardial or endocardial). Conclusion: This pipeline enables construction of physiologically de-tailed BDTs that accurately replicate patient-specific activation and reentry patterns, supporting non-invasive VT risk assessment and guiding personal-ised ablation strategies.