Soft robotic cardiac sleeves: materials, actuation mechanisms and translational pathways.

Heart failure remains a leading cause of morbidity and mortality worldwide, highlighting the urgent need for effective alternatives to heart transplantation. While ventricular assist devices (VADs) have improved survival for patients with advanced heart failure, their long-term use is associated with blood-contact complications, thromboembolic risk, and the need for lifelong anticoagulation. These limitations have stimulated interest in non-blood-contact mechanical circulatory support strategies, particularly devices based on direct cardiac compression (DCC). Recent advances in soft robotics, compliant materials, and bioinspired actuation technologies have enabled the development of soft robotic cardiac sleeves that assist cardiac function by mechanically compressing the heart in synchrony with native myocardial contraction. By avoiding direct blood interaction, these systems aim to reduce thrombogenic risks while preserving physiological cardiac mechanics. This review provides an overview of emerging soft robotic cardiac compression devices, focusing on the materials, actuation mechanisms, and design strategies that enable effective epicardial assistance. Key engineering challenges, including conformal heart-device coupling, cyclic durability, and synchronisation with cardiac dynamics, are discussed. Finally, we outline translational considerations and future research directions required to advance these technologies toward clinical application.