• Lead-field geometry and vector-based cardiac electrophysiology became core: studies mapped how action currents spread in volume conductors, related electrode placement to signal morphology, and formalized heart-vector representations to interpret clinical leads [2], [3], [7], [10], [11].

• Systems mechanophysiology unified cardiac mechanics, conduction, and energetics, treating the heart as an integrated electromechanical pump whose energy output and rhythm arise from coupled regulation across tissues; this framing guided physiology and later interventions [1], [3], [10], [12].

• Regeneration engineering emphasized controllable interfaces and quantitative tracking: rates and determinants of nerve regrowth were measured, interface devices (tantalum cuffs, resin caps) engineered, and graft processing explored, alongside live microscopic models of tissue ingrowth [4], [5], [6], [9], [19], [20].

• Biomaterials-first surgical design emerged: surgeons selected and shaped polymers, metals, and processed tissues to achieve functional repair and biological modulation (e.g., fibrosis, hemostasis), foreshadowing modern device–tissue co-design [8], [9], [16], [17], [18], [20].

• Cardiovascular engineering moved toward structural and perfusion repair: revascularization and septal closure were framed as design problems balancing flow, mechanics, and tissue viability, supported by preservation and testing of vascular grafts [8], [13], [14], [15].