JPS6145735A - R-wave detector of electrocardiograph - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrocardiogram R wave detection device, and more particularly to an electrocardiogram R wave detection device having a parasitic wave removal circuit that removes parasitic waves generated near the peak (=) of an R wave.

As shown in FIG. 1, an electrocardiogram is composed of P waves, Q waves, R waves, S waves, T waves, etc. In a normal waveform, the R wave has a larger peak value than other waveforms and is easier to detect, so by detecting the R wave, heart rate can be counted and arrhythmia can be detected. . However, the second
As shown by the broken line in the figure, artifacts generated from the electrodes and peaks (parasitic waves) caused by electromyograms may occur in the R wave, making it difficult to recognize the R wave.

The present invention has been devised in view of the above drawbacks, and even if parasitic waves occur, they can be removed and R waves can be accurately detected. An object of the present invention is to provide an R-wave detection device.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram of one embodiment according to the present invention. In the figure, (20) is a filter, which extracts signal components including R waves from the electrocardiogram, as shown in FIG. 5 (51).

(21) is a pulsing circuit. This pulsing circuit (2
1) has a threshold function such as the voltage (Es) shown by the dashed line in FIG. 5 (51) determined by the R-wave peak amplitude before the -amplitude. Therefore, Fig. 5 (5
As shown in 2), this is a circuit that only generates a pulse having an amplitude voltage (E2) [■]. (22) is a parasitic wave removal circuit that removes parasitic wave pulses, and FIG. 4 shows a specific configuration of this parasitic wave removal circuit (22).

That is, the input terminal (a) is connected to an inverter (515) (5) via a resistor (5]-1) and a diode (512).
16) are connected in series. The inverter (51
, 5> is configured to start operating at a threshold voltage (E,) [V] or higher.

A DC power supply +vb is connected to the input of the inverter (515) via a resistor (513). Capacitor (5
14) is connected to the human power of the inverter ('515) and the output of the inverter (516). Here resistance (51
3) and the capacitor (514) constitute an integrating circuit.

Next, the operation and effect of the electrocardiogram R wave detection device according to the present invention will be explained below with reference to FIGS. 3, 4, and 5.

The electrocardiogram input is filtered by the filter (20) in FIG. 3, and an R wave as shown by the solid line in FIG. 5 (51) is input to the pulsing circuit (21) in FIG. 3. This Fig. 3 Pulsing circuit (21
) generates an R pulse (RP) as shown in (52), and the parasitic wave removal circuit (
22). At the peak of the R pulsed (RP) input to the parasitic wave removal circuit (22), the diode (5
12), the connection between (,) and (b) becomes open, and the capacitor (514) is charged with a predetermined time constant via the DC power supply +"111)l and the resistance value 13). As a result, the input point When the potential in (b) rises and exceeds the threshold voltage (E4) of the inverter (515), the pulse shown in Figure 5 (54) appears at the output point (c) of the parasitic wave removal circuit in Figure 4. Also, during non-peak times, the diode (512) is short-circuited, and the charge in the capacitor (514) is discharged via the diode (512) and the resistor (511).

Next, the operation and effect when a parasitic wave occurs will be explained.

When a parasitic wave (K) as shown in FIG. 5 (51) is input to the pulsing circuit (21), after the arrival of the R wave as shown in FIG. 5 (51), the threshold voltage (Es) is Because of the drop, the parasitic wave (K) becomes a pulse.

Therefore, along with the R pulsed (RP), the parasitic wave pulse (KP)
) is generated, and the pulse shown in FIG. 5 (52) is input to the parasitic wave removal circuit (22).

The parasitic wave pulse (K
P) charges the capacitor (514) as in the case of R pulsed (RP).

However, as shown in Fig. 5 (51), the parasitic wave (K) with a short time width arrives before and after the R wave, so the pulse width of the parasitic wave pulse is short, so the inverter It is certain that the threshold voltage (E4) of (515) is exceeded. Therefore, the inverter (515) does not operate, and the inverter (515) does not operate.
54), the parasitic wave pulse (KP) is not output in FIG. 4(c).

However, depending on the type of arrhythmia, a waveform similar to a parasitic wave may occur (intraventricular conduction disorder). However, since the pulse width of parasitic waves and the pulse width due to arrhythmia are different, in order to reliably remove only the parasitic waves, a resistor (513) is used to set the pulse width to be removed to, for example, 5 (msec).
If the capacitor (514) is determined as follows, parasitic waves can be removed most efficiently.

The combined configuration of the filter, pulsing circuit, and parasitic wave removal circuit according to the present invention can be put to practical use by appropriately selecting circuit elements, circuit constants, etc., depending on usage conditions, etc.

As described above, according to the electrocardiogram R wave detection device of the present invention, R
A circuit that can reliably detect waves, is particularly good at removing parasitic waves that occur at the peak of R waves, and can clearly distinguish them from arrhythmia, so there is no need to worry about misrecognition, and performs signal processing of R waves. It is possible to sufficiently increase the reliability of the system.

[Brief explanation of the drawing]

Figure 1 is a basic waveform diagram of an electrocardiogram. Figure 2 is a waveform diagram where parasitic waves occur in an electrocardiogram. FIG. 3 is a block diagram showing an embodiment of the electrocardiogram R wave detection device of the present invention. FIG. 4 is a circuit diagram showing an embodiment of a parasitic wave removal circuit. FIG. 5 shows the waveform diagram in FIGS. 3 and 4, and (5
1) is the output waveform diagram of the filter (20), (52) is the output waveform diagram of the pulse generator (21), (53) is the waveform diagram of the input point (:]) in Figure 3, and (54) is the parasitic wave. Removal circuit (22
) is an output waveform diagram. (20): Filter, (21): Pulsing circuit, (22
): parasitic wave removal circuit, Es: threshold voltage, E,: amplitude value of R wave at the output of filter (20),
E2: Pulse amplitude value of the output pulse of the pulse generator (21), E3: Same as E2, E4: Inverter (5
15) Threshold voltage. Patent applicant: Advance Development Institute Co., Ltd. Figure 1
Figure 2R Figure 3Rumatada〃 Figure 4Figure 5

Claims (1)

[Claims] A filter for extracting R waves from the input electrocardiogram signal, a pulsing circuit for the R waves extracted by this filter, and integrating the output pulses output from the pulsing circuit and the pulsing circuit, An electrocardiogram R wave detection device comprising: a parasitic wave removal circuit for removing a parasitic wave pulse generated at an R wave peak by comparing the integral value with a threshold comparison circuit.