A Computational Journey Toward an Optimal Design for Metamaterial Epicardial Passive Sleeves.

Heart failure (HF) following myocardial infarction (MI) is a major clinical challenge with severe complications. Epicardial sleeves and patches are increasingly investigated to improve heart function post-MI, yet their passive mechanical effects remain underexplored. This has resulted in limited insight into how sleeves mechanically interact with the infarct and remote myocardium. This study used 3-D in-silico cardiac models to examine how sleeve shape, material properties, and architecture affect global and regional mechanics. A high-fidelity biventricular model is used to investigate how a continuum cardiac sleeve alters function. Designs that improve regional mechanics successfully limited pathological bulging, modulated fiber strains, and influenced torsional behavior without over-constraining remote tissue, whereas overly restrictive and stiff sleeves penalized healthy myocardium and reduced the intended relief of infarct bulging. These findings highlight the importance of considering regional biomechanical markers when developing sleeve designs. Building on these continuum sleeve insights, a spheroidal left ventricle model demonstrated the proof-of-concept advantage of an "auxetic" metamaterial sleeve, engineered with a negative Poisson ratio. This programmed architecture provided region-specific benefits beyond those of conventional continuum sleeves. Ultimately, this work contributes to an improved understanding of passive sleeve-heart interactions and improves the targeted biomechanical support therapies following MI.