Dr Tim Rowsell and colleagues at Cambridge University Engineering Department are developing a miniature heart beat recorder which could form the basis of a personal health monitor. The project is funded jointly by the RHA and the MRC and forms part of an investigation into normal patterns of human energy expenditure with Dr. Nick Wareham of the Department of Community Medicine.
The prototype must record hearts beats continuously over a period of weeks. This poses several challenges to the design. Firstly the device must be comfortable to wear and unobtrusive to all aspects of daily life. To achieve this objective the recorder is to consist of a single miniature device which will be simply held in place on the chest (there will no trailing connections or separate attachments). Secondly the recorded information must be accessible for analysis. Finally the recorder must be absolutely reliable.
The new monitor will offer several advantages over existing devices, the most important of these is the ability to record heart beats over extended periods and the integration of the recorder into one small unit.
Recording heart beats is merely the first step. The aim of the program is to then extend the capability to record other human physical parameters for example skin temperature, respiration. The medical applications for such a system are clear; the development of a better understanding of normal human activity leading to a more timely and precise diagnosis of ill-health. The application for sports training is also fairly self evident. But in this age of personal telephones, digital assistants and smart cards other more esoteric applications may be realised; a personal 'black box' recorder?
Further information about the background to this project (including a discussion of a linked research project in which instrumentation and techniques for fetal heart-rate monitoring were investigated) is available on the web.
The prototype heart monitor has recently been tested in the Engineering Department and Clinic.
The prototype consists of a small (125mm x 25mm x 12mm) unit which attaches to the chest via a belt. Once connected this 'standalone' unit detects and records heart rate. The heart rate count is saved each minute to non-volatile memory. At the end of the recording period the device can be attached to a PC and the information downloaded for further analysis. The limit for the recording period, determined by the memory size is currently 5 days, assuming recording for 16 hours per day.
Tests were to