The pseudo-beating heart model: A dynamic ex vivo simulator for myocardial wall stress and suture performance

ObjectiveDurable repair of penetrating cardiac injuries remains technically challenging, particularly when performed under load in the absence of cardiopulmonary bypass. Conventional sutures are prone to tear-out under dynamic wall stress, and current ex vivo models fail to replicate realistic ventricular mechanics. This study presents a physiologically relevant ex vivo platform, termed the Pseudo-Beating Heart (PBH) model, for evaluating myocardial injury mechanics and suture performance under controlled pulsatile ventricular loading.MethodsFresh porcine hearts were prepared and equipped with a dual-balloon system simulating ventricular preload, afterload, and cyclic ventricular deformation (80 bpm). Intraventricular pressures were recorded continuously, and wall tension was estimated using a thick-wall Laplace model. Standardized transmural injuries (1 cm) were introduced to assess cleft widening and pressure loss under cyclic loading. Hysteresis loop areas were calculated to characterize viscoelastic fatigue. Hearts were obtained from unrelated terminal animal studies in accordance with 3R principles; no animals were sacrificed specifically for this model.ResultsPhysiologically relevant ventricular pressure ranges (LV: 130/10 mmHg; RV: 40/8 mmHg) were stably maintained. Transmural injuries produced reproducible wound gaping (up to 6.1 cm) and pressure loss (10-17%). Wall tension and hysteresis behavior correlated with published biomechanical data. The model enabled consistent evaluation of repair techniques under defined mechanical load.ConclusionThe PBH model provides a reproducible, physiologically relevant ex vivo platform for testing myocardial repair strategies under pulsatile ventricular loading. It offers potential value as a low-resource, ethically compliant simulator to bridge the gap between bench-top testing and subsequent in vivo validation of trauma repair techniques and extracorporeal support strategies.