LAUREAT – Leadless Cardiac Implants Including Reliable and Robust Piezoelectric Energy Harvesting Devices

Abstract

Today’s pacemakers are already pretty small, about 8 cm3, but to insert one a surgeon has to cut open a patient to install the device on the right side of the chest, near the heart. Wires, called leads, are then connected from the pacemaker through the veins to the stimulation locations within the heart, in order to provide electrical stimulation to the heart muscle. The leads are often pointed out as the weakest element in a pacing system. Examples of lead problems include: lead dislodgment lead malfunction, lead fracture, lead infection, cardiac perforation, coronary sinus dissection, vein thrombosis, cardiac valve injury, or lead thrombi. Overall, pacing lead failure occurs up to 21% of the time within 10 years after pacemaker implantation. Progress in microelectronics and micro-sensor technology has enabled make all pacemaker components to fit in a very small volume (< 1 cm3). Such a tiny pacemaker can be directly implanted on the endocardium within a heart cavity without any lead. Hence, this is called a leadless pacemaker. Leadless pacemakers are expected to make a revolution on the next generation of pacemakers. Their main advantage is to remove leads. Moreover, it is believed that a leadless device would be much easier to implant. Therefore it should decrease the implantation time and the associated costs, and improve the patient comfort. Several companies such as SORIN Group, Medtronic, St Jude Medical and EBR System are developing their own leadless solutions. For this purpose, all pacemaker components (packaging, electronic circuits and micro-sensors) have reached industrial maturity for leadless implementation, except for the power source. Considering the current state-of-the art of lithium-based technology used to power pacemakers, a 0.6 cm3 battery could last approximately from 7 to 9 years. However, although the replacement of a current pacemaker is a common and relatively simple procedure, a replacement of a leadless pacemaker would be much more difficult. Hence, a solution would be to implant supplementary capsules without extracting those whose batteries are depleted. This however can take very significant space in the heart and can hinder its operation. Therefore, long lasting regenerative energy sources as alternatives to traditional batteries are particularly interesting for leadless pacemakers. In a previous FUI project led by SORIN, it has been validated that a dedicated piezoelectric micro-scavenger could collect mechanical energy from human heart motion and could convert it into electrical energy with sufficient level for powering a leadless pacemaker. With scientific objectives focused on reliability and robustness of piezoelectric scavengers, LAUREAT project aims at developing a fundamental technological building block which is the corner stone on the way to the industrialization of future cardiac implants (medical) and more generally self-autonomous sensors (industry). LAUREAT project aims at overcoming several technological and scientific barriers: Long term reliability of piezoelectric materials/devices, ageing effects over performances, defect mechanisms of piezoelectric materials/devices, design for reliability, reproducible manufacturing technology for materials at the frontier of bulk materials and thick films, high yield volume production with competitive cost. The project demonstrator will address a new piezoelectric μ-scavenger that converts heart motion into usable electrical energy. The scavenger will be designed to maximize conversion efficiency with high degree of reliability and robustness. It is here proposed to pave the way towards industrialization of reliable and self-autonomous leadless pacemakers as an alternative to current battery-powered implants. LAUREAT’s objective is to provide autonomous and robust solutions that will last for more than 20 years in operation (instead of less than 9 years for battery solutions) preventing replacement surgery for patients and reinforcing the competiveness of medical device industry in Europe.