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1. WO2004100785 - DISPOSITIF DE MESURE ET TRANSMISSION SANS FIL DE SIGNAUX D'ECG

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

A device for measurement and wireless transmission of
ECG-signals

This invention concerns a method for measurement, wireless transmission and analysis of electrocardiogram signals (ECG) . More specifically, it concerns a method in which measurement of ECG-values is carried out by means of a measuring unit that is attached to the patient to be monitored, and that is provided with an amplifier and a transmitter. The measuring signal is transmitted wirelessly from the measuring unit to a local apparatus wherein the measuring signal is analysed.
Then, the signal and/or a warning of an alarm condition possibly may be transmitted to a monitoring station located at a larger distance from the patient. The invention also comprises a device for carrying out the method.

Patients, in the form of human beings or animals, having a need for periodical or continuous ECG- onitoring
traditionally have depended on being connected to wire-connected monitoring equipment that, by and large, must be monitored by qualified personnel with respect to, among other things, the values and patterns of the signals.

Document DE 10048764 describes an amplifier unit connected, by means of conductors, to electrodes on a patient, the amplifier being connected to a mobile telephone for
displaying the ECG-signal.

Document US 2002/0072682 concerns a device, wherein
disposable electrodes are connected, in a known manner, to an amplifier and a transmitter, after which the ECG-signal is transmitted to a receiver.

Thus, it is known to communicate real-time ECG-signals by means of a radio connection. According to the aforementioned documents, however, a flexible wire connection from the particular measuring electrode to the transmitter is relied on. Also, qualified personnel substantially monitoring the measuring signals continuously are relied on.

The object of the invention is to remedy the disadvantages of prior art.

The object is achieved in accordance with the invention and by means of the features disclosed in the following
description and in the subsequent claims .

A wireless measuring unit, which may be disposable, is placed on the body of the patient. For disposable use, the measuring unit may be designed to last a few days. The wireless
measuring unit is formed with at least one electrode
connected to a transmitter via an amplifier. An apparatus located in the vicinity receives the amplified measuring signals transmitted from the measuring unit via the
transmitter, preferably in an encrypted format. The apparatus may be carried by, or be in vicinity of, the patient. No wire connection exists between the measuring unit and the
apparatus, thereby providing the patient with a significantly improved freedom of movement relative to that of prior art.

The apparatus is provided with an analysis unit comprising a memory chip for storage of measurement lapses, typically a duration of several seconds. Based on recognition of
corresponding, for example pre-programmed, measuring value limits and/or patterns, the analysis unit is arranged to recognize courses in measuring values indicating, for
example, heart disease in the patient. Typically, the
measuring signal is analysed with respect to amplitude, rise-time, width and frequency.

The apparatus may be provided with a transmitter arranged to transmit an alarm warning to a monitoring station wherein qualified personnel may be located. It is also advantageous to transmit, together with the alarm, an excerpt of the measurements taken at times close to the time of the alarm moment, thereby supplying the personnel with data enabling them to evaluate the condition of the patient and
simultaneously transmitting an identification of the patient.

Moreover, it may be advantageous to provide the apparatus, or a unit carried by the patient, with a position-informing device for the personnel to determine the whereabouts of the patient.

Preferably, the wireless measuring unit comprises two
separate electrodes in the form of electrically conductive contact surfaces arranged to rest against the skin of the patient. The measuring unit is formed so as to make the connecting conductor between the contact surfaces and the signal amplifier of the measuring unit, very short.

The short connecting conductor is subjected only
insignificantly to disturbances. Therefore, it suffices to correct the measuring signal from the electrodes by means of so-called over-sampling, which implies collecting more measurements than those being transmitted, and using these "redundant" measurements to correct the measurements to be transmitted. Thus, it suffices to use two electrodes in instances wherein, according to prior art, three or more electrodes must be used to allow filtering out of noise.

In an alternative embodiment, the measuring unit is attached to a signal processing device arranged to convert the measuring signal in a manner allowing it to be forwarded for further processing by means of a standardized communication protocol, for example Bluetooth.

In the following, a non-limiting example of a preferred method and embodiment is described and illustrated on the attached drawings, in which:

Figure 1 schematically shows a patient carrying an attached measuring unit, the measuring unit communicating with an apparatus onwards to a monitoring station;

Figure 2 shows, in larger scale, the measuring unit viewed from the side being attached to the patient;

Figure 3 shows a section II-II of figure 2;

Figure 4 schematically shows main components of the measuring unit;

Figure 5 schematically shows main components of the
apparatus;

Figure 6 shows an alternative embodiment wherein the
measuring unit is provided with a signal processing device; and

Figure 7 shows main components of the signal processing device .

On the drawings, reference numeral 1 denotes a measuring unit attached to a patient 2 and comprising two electrodes in the form of electrically conductive contact surfaces 4, the contact surfaces 4 being connected, via respective conductors 6, to an analogue amplifier 8. Prior to being transmitted from the measuring unit 1 via a first transmitter 12 and a first aerial 14, the signal is processed in a first signal converter 10. The signal is transmitted as a frequency modulated radio signal from the first aerial 14.

The components 8, 10 and 12 are provided with energy from a battery 16. A component carrier 17 is provided with necessary electrical conductors (not shown) and is arranged to
constitute a supporting element for the components 4, 6, 8, 10, 12 and 14 connected to the measuring unit 1, cf.
figure 3.

An encapsulation 18 provided with a glue surface 19 at the side thereof facing the patient 2, encloses the component carrier 17 and said components. Preferably, the encapsulation 18 is made from a relatively flexible, possibly fibre-reinforced and sterile material.

Via a second aerial 22 and a second amplifier 24, an
apparatus 20 is arranged for receiving signals from the measuring unit 1 and to convert the signal to an appropriate signal for analysis in a first processor 32 by means of a second signal converter 26, a first digitizer unit 28 and a third signal converter 30. The apparatus 20 is provided with a storage unit (not shown) for program code and signal values, and a radio connection based on standard mobile telephone technology may be used, for example GSM (Global System for Mobile Communication) .

If a measuring value and/or a measured signal pattern changes in such a way that it exceeds previously determined limits, the first processor 32 is arranged for analysing the signal from the third signal converter 30 and to deliver a warning to a monitoring station 34 via a second transmitter 36 and a third aerial 38.

Said components of the apparatus 20 are provided with energy from an energy source 40.

In an alternative embodiment, cf. figures 6 and 7, the measuring unit 1 is provided with a signal processing device 50. The signal processing device 50 is connected to the measuring unit 1 by means of an attachment 52. Communication between the measuring unit 1 and the signal processing device 50 may be established by means of a conductor 54, cf . figure 6, or it may be wireless, cf. figure 7.

When the signal communication with the measuring unit 1 is wireless, the signal processing device 50 comprises a fourth aerial 56 and a second receiver 58 arranged to convey measuring signals from the measuring unit 1 to a second digitizer unit 60, after which the signal is processed in a processor 62 provided with a storage unit (not shown) for program code and signal values .

The signal is forwarded from the processor 62 via a fourth signal converter 64, a third transmitter 66 and a fifth aerial 68 to a receiver (not shown) for further processing.

Said components of the signal processing device 50 are provided with energy from a second battery 70.