UC Irvine

Two fields of cardiovascular energy harvesting are investigated, (1) stents and (2)

leadless pacemaker. The demand for rechargeable technologies in cardiovascular stents

arose from the unmet clinical need for real-time tracking of re-occlusions in implantable

stents. This thesis entertains the idea of piezoelectric cantilevers positioned at the

inlet/outlets of the stent to harness the pulsatile blood flow within arterial cavities to

power wireless communication circuits to notify physicians of plaque growth. A MATLAB

study utilizing literature-based blood flow velocities in both healthy and diseased patients

yielded 3.5mV energy harvesting potentiality. Then, a large-scale benchtop study

successfully produced a simplistic model to see if the pressure differences expected across

the stent (.4 Pa). Both tests prove the feasibility of such a design. With a 95% reduction in

volume from its predecessors, the leadless pacemaker traded compatibility with battery

longevity going from a 10-year device lifetime to 6 years [3,34]. Enclosed is an energy

harvesting accessory intended to slip around leadless in-ventricular pacemakers such as

the Medtronic Micra. Two designs featured mechanisms to harvest the blood pressure and

the ventricular wall force from within the heart cavity via electromagnetic induction by ferrofluid and solid ring magnets. The team promptly abandoned the ferrofluid mechanism due to its limited induction capabilities after its 20x deficiencies compared to solid core magnets demonstrated by multiple benchtop tests. However, the solid ring magnet design

proved successful after meeting eight out of nine acceptance criteria through simulation

studies [Modal/Fatigue/Induced Voltage/Heat Generation/Mesh compliance] and

benchtop studies [Induced Voltage/Magnet Shielding/Heat Generation].