IMEC has developed a wireless ECG (electrocardiography) patch for the continuous monitoring of cardiac activity and heart rate. Wearable, wire-free and easy to set-up, the system removes disturbances and discomfort caused by current cardiac monitoring systems. This is a major advantage for body-worn sensors, a key theme in the Human++ program within the Holst Centre.
The ECG patch is a hybrid system combining electronic assembly on a flexible Polyimide substrate and textile integration. This allows achieving flexibility and stretchability. Standard ECG electrodes are used for attachment to the body. The ECG patch can fit body curves and allows optimal, personalized, placement of the electrodes. It can therefore be used to monitor cardiac activity ‘on-the-move’ in daily-life conditions, thus opening new perspectives for cardiovascular disease management. Placed on the arm or on the leg, the same system can also be used to monitor muscle activity (EMG).
The core of the wireless ECG patch consists of a miniaturized wireless sensor node integrated on a flexible, Polyimide, substrate. It integrates IMEC’s proprietary single-channel ultra-low-power biopotential ASIC for the monitoring of the ECG signal. It also includes a commercial microprocessor enabling local digital signal processing, a 2.4GHz radio link and a miniaturized rechargeable Lithium-ion battery. The battery is placed under the electronic components to ensure the local rigidity required for long-term functioning of the electronic components. In addition, the sensor node features a fork-antenna and a snap-on connector (for connection to the electrode). The total size of the flexible core part is 60x20mm2. Two additional snap-on connectors are coupled to the central part with short conductive wires. The complete system is then integrated into textile to form the ECG patch. The use of very short wires and their integration into textile allows the minimization of an important source of artifacts due to wire movement.
The wireless ECG patch can work in continuous monitoring mode, in which the ECG – or EMG – data is continuously transmitted to the receiver (sample frequency between 250 and 1000Hz). For cases in which only heart rate information is required, the heart rate can be computed locally on the node and then sent over-air to the receiver. This allows drastic reduction of the use of the radio and hence increases the autonomy of the system. The embedded miniaturized rechargeable battery offers a capacity of 175mAh, which allows for an optimal autonomy of the system varying from one day in continuous monitoring to several days for simple heart rate monitoring. The signal is sent to a receiver connected to a PC or to a data-logger for later download on a computer.
In the next development phase, the demonstrator will be demonstrated and tested in clinical trials. A few more years are expected to be needed before companies will integrate the technology in actual products.
The system is a tangible demonstrator of the Human++ program researching healthcare, lifestyle and sport applications of body area networks. Interested parties can get more insight in this research or license the underlying technologies through membership of the program.
IMEC is a world-leading independent research center in nanoelectronics and nanotechnology. Its research focuses on the next generations of chips and systems, and on the enabling technologies for ambient intelligence. IMEC’s research bridges the gap between fundamental research at universities and technology development in industry. Its unique balance of processing and system know-how, intellectual property portfolio, state-of-the-art infrastructure and its strong network of companies, universities and research institutes worldwide position IMEC as a key partner for shaping technologies for future systems. IMEC vzw is headquartered in Leuven, Belgium, has a sister company in the Netherlands, IMEC-NL, concentrating on wireless autonomous transducer solutions, and has representatives in the US, China and Japan. Its staff of more than 1500 people includes more than 500 industrial residents and guest researchers. In 2006, its revenue (P&L) was EUR 227 million.
About the Holst Centre
The Holst Centre was set up in 2005 with support from Economic Affairs of the Netherlands and the Flemish Government and is located on the High Tech Campus in Eindhoven. The center is the creation of IMEC (Flanders, Belgium) and TNO (The Netherlands) and will grow into an international recognized open R&D institute that develops generic technologies and technology platforms for autonomous wireless transducer solutions and systems-on-foil. The activities on wireless autonomous transducer solutions in the Holst Centre are run by IMEC-NL, the sister company of the Belgian research centre IMEC. Interaction and cooperation with both academia and industry, including small- and medium-sized enterprises, enables the Holst Centre to tune its scientific strategy to the long-term corporate strategies of its partners. A beneficial transfer of technology to the industry is guaranteed and market requirements can be anticipated.