Interventional placement of thin coil shaped implants powered wirelessly for monitoring vital signals and controlling abnormal activities by electro-stimulation

Abstract

Various types of implants are being commonly used for monitoring vital signals and controlling the critically ill patient's condition such as arrhythmia, sick sinus syndrome, etc. For implanting these medical devices under the skin, surgery is inevitable. These days many patients are more willing to accept interventional therapies that are less invasive, especially inserting a catheter into a blood vessel or endoscopy through a natural orifice. To be able to use interventional therapy for implanting medical devices, they will need to be small enough to fit them through a catheter or the forceps channel of an endoscope. We evaluated a wirelessly powered prototype of a thin coil shaped (diameter 0.05 inches) implant for electrocardiogram (ECG) monitoring and controlling abnormal heart rhythms. An extracorporeal unit fed power to the sensors and transceiver circuit. We are planning to add sensors for detecting ECG signals and also a pulse generator for transmitting signals to the heart. At 13.6MHz, 10mW was wirelessly transferred from the helical antenna attached to the chest wall of the phantom to the coil's receiving antenna and the power enabled the sensors and circuits to work. Moreover, the coil's receiving antennas worked as stimulating electrodes similar to a pacemaker lead.