Soft Robotic Cardiac Sleeves: Materials, Actuation Mechanisms, and Translational Pathways

Abstract

Heart failure remains a leading cause of morbidity and mortality worldwide, highlighting the urgent need for alternatives to heart transplantation. While ventricular assist devices (VADs) improve survival in advanced heart failure, their long-term use is limited by blood-contact complications, thromboembolic risk, infection, and the requirement for lifelong anticoagulation. These limitations have stimulated growing interest in non-blood-contact mechanical circulatory support strategies based on direct cardiac compression (DCC). Recent advances in soft robotics, advanced functional materials, and artificial muscle technologies have enabled the development of soft robotic cardiac sleeves capable of mechanically assisting the heart by applying synchronized epicardial compression and torsion. By avoiding direct blood interaction, these systems offer a potential pathway to reduce thrombogenic risks while preserving physiological cardiac mechanics. This review provides a comprehensive overview of emerging soft robotic cardiac compression devices, focusing on the materials platforms, actuation mechanisms, and structural design strategies that enable effective epicardial assistance. We discuss key classes of actuator materials—including pneumatic elastomers, electroactive polymers, dielectric elastomers, twisted-and-coiled polymer muscles, and shape-memory systems—and examine their performance characteristics for cardiac applications. Critical engineering challenges such as conformal heart–device coupling, cyclic durability, physiological synchronization, and power delivery are also analysed. Finally, we outline translational considerations and future research directions required to advance soft robotic cardiac sleeves toward clinically viable next-generation cardiac assist technologies.