High Energy Density Polymer Film Capacitors for ICDs

项目总结:

Project Summary: An implantable cardioverter defibrillator (ICD) is a small battery powered electric pulse generator about the size of a stopwatch that is implanted into the chest of patients who are at risk of sudden cardiac death due to ventricular fibrillation and ventricular tachycardia. The ICD uses a capacitor to deliver a shock (defibrillation) to the heart, which stops the abnormal rhythm. Without this therapy, the dangerously rapid rhythm could lead to sudden cardiac arrest and sudden cardiac death within minutes. Sudden death due to cardiac arrest affects 330,000 people each year in the United States alone (meaning that almost 1,000 people die from it each day). ICDs have been shown to effectively stop 95% or more of these dangerously fast heart rhythms. ICDs place unique requirements on the capacitor used to generate the electrical pulse, requiring a combination of high voltage, high capacitance, and small case size. While metalized polymer film capacitors are used AEDs, the energy density of current materials is too low to be used in implantable devices. Without the availability of high energy density polymer films, ICDs have been limited to aluminum electrolytic capacitors, which are undesirable for many reasons resulting from the use of a liquid electrolyte. Polymer film capacitors are solid state and thus require no volatile compounds that would pose safety risks once implanted. Existing polymer film capacitors, such as those produced from polypropylene or polyethylene, have a low volumetric capacitance and low energy density (~1.2J/cc) making them unsuitable for ICDs. HARP Engineering recently developed a new composition for thin film capacitors that provides the highest energy density ever reported. This technology is would allow a 7.7 times smaller capacitor than the aluminum electrolytic capacitors used in current implantable cardioverter defibrillators (ICDs) and a 28.7% reduction in total device volume. Since ICDs are implanted, the package size is critical to the patient's quality of life after surgery, especially in pediatric cases and the reduction of late complications, such as skin erosion, which is highly impacted by the size of the device and reported to occur in 0.9% of cases. Furthermore, the more recent development of subcutaneous ICDs which eliminate complications from intravenous leads require roughly three times greater energy to achieve defibrillation thus producing even greater need for smaller capacitors. Under this SBIR, HARP Engineering proposes to collaborate with St. Jude Medical and Boston Scientific to manufacture, test and demonstrate ultra high energy density capacitors for use in ICDs.