Introduction: Ventricular remodeling due to intrauterine growth restriction (IUGR) results in a decreased sphericity index (SI), attributed to an increased left wall thickness and a reduced apex-base length. This study aims to assess how the reduced SI, caused by IUGR, affects electrophysiological properties, using biophysically detailed in silico models.
Methods: We used a computational biventricular model based on a realistic heart and torso model. To simulate the effects observed in IUGR subjects, we built a more globular model by reducing the base-to-apex length, enlarging the basal diameter and increasing the left wall thickness. Spatial principal component analysis was applied to the pseudo 12-lead ECG, to emphasize the QRS and T-wave separately. Wave delineation was then performed to measure QRS width, Tpe, and QT intervals and amplitudes, which were compared with previously reported clinical findings.
Results: The IUGR model exhibited a longer QRS width and a larger R-wave amplitude when compared to the control model in agreement with clinical findings. The simulated repolarization Tpe and QT intervals, and the ratio Tpe/QT did not show differences between the IUGR and control models. Clinical findings showed, however, increased Tpe and Tpe/QT in IUGR subjects.
Conclusion: The simulated reduction in SI and the widening of the left ventricular wall led to an increase in both the QRS width and the amplitude of the R-wave, aligning with clinical data. There was no impact on the QT interval, still consistent with clinical observations. While the geometric change resulting from IUGR impacted the QRS complex, the Tpe, QT, and Tpe/QT remained unchanged, suggesting ionic remodeling not considered in the simulation.