Energy harvesting from pulsatile Superior Vena Cava for implantable devices

A pacemaker is an implantable electronic medical device powered by a lithium-iodine battery and designed to regulate abnormal heart rhythms via electrical pulses. One of the major limitations of such devices is the finite battery lifespan, necessitating surgical replacement. This study explores the feasibility of harvesting energy from pulsatile blood flow in large veins, specifically the Superior Vena Cava (SVC) to supplement or extend the battery life of implanted devices such as pacemakers. An experimental setup was developed to simulate the pulsatile flow in the SVC using a hydraulic system driven by a cam mechanism to replicate the physiological blood velocity profile. A Polyvinylidene Fluoride (PVDF) piezoelectric sensor, positioned within the flow stream, undergoes harmonic deformation due to fluid-induced forces, thereby generating electrical charges through the piezoelectric effect. Output voltage and power were measured across a range of resistive loads under four heart rates: 60, 80, 100, and 120 beats per minute (bpm). The corresponding peak power outputs were 0.5, 2, 8.5, and 35 nW, with steady-state voltages of approximately 0.3, 0.5, 1.0, and 1.7 V, respectively. The process was further modeled using Finite Elements simulation and MATLAB, with the simulation results showing strong agreement with experimental trends. Simulated power outputs were 2, 7.5, 20, and 45 nW at the respective heart rates. Although the harvested power is modest, it demonstrates potential for enhancing device longevity. Future improvements—such as deploying multiple harvesters, optimizing device geometry, and substituting PVDF with higher-performance materials like Lead Zirconate Titanate (PZT) could significantly improve energy harvesting efficiency in implantable medical electronics.