A 97-Channel Read-Out ASIC for an Electrophysiological Mapping Catheter With an Optical Link.

Electrophysiological (EP) mapping catheters are medical equipment, which are widely used to diagnose and treat atrial fibrillation. The electrophysiology signals are sensed by the catheter's electrodes, for which a large electrode count becomes more and more essential because of the demand for a higher local resolution. A drawback of the large electrode count is the effort to pass through and to integrate the wires inside the catheter shaft. To overcome with this issue, this article describes the realization of an EP ASIC, which is placed close to the 97 electrodes and to perform an in-tip digitization. Thanks to an integrated optical link, only a single fiber is required to connect the catheter tip to an externally located electro-optical unit and thus shrinking the shaft volume to a minimum. The fiber is used to guide light from the electro-optical unit to the catheter tip and illuminate a blue LED, which is located close to the EP ASIC and acts as a photovoltaic cell. The EP ASIC is designed to use the LED as power source and a data transceiver while performing signal conditioning and digitization of the EP signals at the same time. The EP signals are captured with the ASIC's multi-channel read-out circuit consisting of 97 fully differential preamplifiers and additional filter stages. A switch network sequentially selects one single channel for further amplification and digitization of the EP signal. The read-out circuit is designed to process signals in the range of 500 µVpp to 20 mVpp with a bandwidth of 5 Hz to 100 Hz.

First Dedicated Balloon Catheter for Magnetic Particle Imaging.

Vascular interventions are a promising application of Magnetic Particle Imaging enabling a high spatial and temporal resolution without using ionizing radiation. The possibility to visualize the vessels as well as the devices, especially at the same time using multi-contrast approaches, enables a higher accuracy for diagnosis and treatment of vascular diseases. Different techniques to make devices MPI visible have been introduced so far, such as varnish markings or filling of balloons. However, all approaches include challenges for in vivo applications, such as the stability of the varnishing or the visibility of tracer filled balloons in deflated state. In this contribution, we present for the first time a balloon catheter that is molded from a granulate incorporating nanoparticles and can be visualized sufficiently in MPI. Computed tomography is used to show the homogeneous distribution of particles within the material. Safety measurements confirm that the incorporation of nanoparticles has no negative effect on the balloon. A dynamic experiment is performed to show that the inflation as well as deflation of the balloon can be imaged with MPI.

A 96-Channel Electrophysiology Catheter with Integrated Read-Out ASIC and Optical Link.

This paper describes a realization of an electrophysiology (EP) catheter with 96 electrodes which requires no electrical wiring to the outside by relying on an optical link for both power supply and data communication. The catheter tip is constructed from a liquid crystal polymer (LCP) material. It features 96 gold electrodes, which are uniformly arranged along an expandable basket. An integrated ASIC amplifies, filters and digitizes the EP signals and establishes communication to a data processing unit outside the patient's body. The optical interface consists of a conventional multi-mode fiber and a single blue LED inside the catheter. The external unit used to generate optical power, establish communication and perform data post-processing comprises a laser module, optics, and electrical components. The catheter is designed to capture EP signals in the range of 600 µVpp to 20 mVpp in a frequency range between 8 Hz and 120 Hz.

Controlled delivery of naltrexone by an intraoral device: in vivo study on human subjects.

Naltrexone is widely used in the treatment of opiate addiction but its current peroral administration is characterized by low bioavailability with various side effects. The development of a long-acting transbuccal delivery device (IntelliDrug) for NLX may be useful to improve patient compliance and the therapy effectiveness. The aims of the study are (a) to test basic safety and effectiveness of controlled transbuccal drug delivery on human subjects; (b) to compare NLX bioavailability following transbuccal delivery vs per os conventional delivery; and (c) to test the hypothesis that transbuccal delivery is more efficient than the conventional route. In this randomized cross-over pilot study, 12 healthy subjects received in a different order 2 types of NLX administration, per os or transbuccal delivery, based on which group they were randomized to. For per os administration 50mg NLX tablets were used, while for transbuccal administration, a NLX-loaded prototype of the IntelliDrug device was fixed on patients' dental arch. Serial blood samples were drawn and analysed for the NLX concentration. The IntelliDrug prototype functioned properly and it did not exert any adverse side-effect. The transbuccal route resulted in administration efficiency 4-17 times higher than conventional per os route. Transbuccal delivery of NLX appears to be a more efficient drug administration route compared to peroral one. It allows to reach a given therapeutic blood level using a small drug dose.

A novel fully implantable wireless sensor system for monitoring hypertension patients.

This paper presents a novel fully implantable wireless sensor system intended for long-term monitoring of hypertension patients, designed for implantation into the femoral artery with computed tomography angiography. It consists of a pressure sensor and a telemetric unit, which is wirelessly connected to an extracorporeal readout station for energy supply and data recording. The system measures intraarterial pressure at a sampling rate of 30 Hz and an accuracy of ±1.0 mmHg over a range of 30-300 mmHg, while consuming up to 300 µW. A special peel-away sheath introducer set was developed to support the implantation procedure. The system delivered stable measurements in initial animal trials in sheep, with results being in good agreement with reference sensor systems.

Bioavailability in vivo of naltrexone following transbuccal administration by an electronically-controlled intraoral device: a trial on pigs.

Naltrexone (NLX), an opioid antagonist, is widely used in the treatment of opiate addiction, alcoholism and smoking cessation. Its current peroral administration induces various adverse side effects and has limited efficacy since bioavailability and patient compliance are poor. The development of a long-acting drug delivery system of NLX may overcome the current drawbacks and help in the improvement of treatment of addiction. The primary endpoints of this study were: a) to compare the NLX bioavailability and pharmacokinetics after delivering a single transbuccal dose, released by a prototype of intraoral device, versus an intravenous (I.V.) bolus of the same drug dose; b) to verify the functioning of a prototype of a new intraoral device in vivo; c) to evaluate the permeation enhancement effect of iontophoresis; d) to assess any histomorphological changes in the buccal mucosa after transbuccal delivery. The system was tested on 6 pigs in a cross-over trial. Venous blood samples were drawn at a fixed timetable from the beginning of drug administration and analyzed for the presence of NLX, using an LC/MS/MS method. A punch biopsy was performed for histological analysis after the final experiment. The administration of I.V. NLX induced a sharp increase in blood levels after 5 min and then a steep decrease. In contrast, transmucosal delivery resulted in a gradual increase in blood NLX levels, reaching its peak after 90 min, followed by a slow decrease. After 6h the blood levels of NLX delivered through the buccal mucosa were higher as compared to I.V. administration. No signs of flogosis or tissue damage were histologically highlighted. These results suggest that buccal delivery by an intraoral electronic device could potentially induce long-lasting, continuous and controlled blood levels of NLX, avoiding at the same time spikes of drug plasma levels typical of the I.V. administration route.