CN112263781A

CN112263781A - Beat-to-beat monitoring system and method for implantable cardiac pacemaker

Info

Publication number: CN112263781A
Application number: CN202011311383.6A
Authority: CN
Inventors: 金华; 任江波; 陈小龙; 朱妙娜; 郝云龙; 张鸿
Original assignee: Lepu Medical Electronics Technology Co ltd
Current assignee: Lepu Medical Electronics Technology Co ltd
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2021-01-26

Abstract

The application discloses a beat-to-beat monitoring system and method for an implantable cardiac pacemaker.A ventricular pacing circuit unit is electrically connected with a beat-to-beat monitoring unit; the hop-by-hop monitoring unit is electrically connected with the standby pulse monitoring unit and is used for collecting the ER wave generated by Vp, and judging and outputting the capture/loss state of Vp; the standby pulse monitoring unit is electrically connected with the ventricular pacing circuit unit and used for triggering the ventricular pacing circuit unit to deliver a ventricular standby pulse Vp (B) after delivering the ventricular pacing pulse Vp when the output state of the ER wave Vp is loss of capture, collecting the ER wave Vp (B), judging and outputting the capture/loss state Vp (B), and prolonging the AV interval when the output state Vp (B) is loss of capture; the ventricular threshold searching unit is electrically connected with the standby pulse monitoring unit and used for triggering the ventricular threshold searching unit when the output state of Vp (B) is capture, obtaining a ventricular pacing threshold and resetting ventricular pacing output.

Description

Beat-to-beat monitoring system and method for implantable cardiac pacemaker

Technical Field

The present application relates to the field of cardiac pacemaker technology, and in particular, to a beat-to-beat monitoring system and method for an implantable cardiac pacemaker.

Background

The purpose of the ventricular pacing beat-to-beat monitoring function of the implantable cardiac pacemaker is to acquire an ER wave (i.e., depolarization wave) generated by each ventricular pacing pulse Vp and determine whether Vp captures the ventricle through the ER wave. When the judgment result of the beat-to-beat monitoring is capture, the pacemaker keeps a conventional working state; when the judgment result of the beat-to-beat monitoring is loss of capture, the pacemaker immediately sends a ventricular standby pulse Vp (B) and starts ventricular threshold value search to obtain a current ventricular pacing threshold value, so that reasonable ventricular pacing output energy, namely ventricular pacing output energy with pulse amplitude higher than the threshold value, is set according to the obtained threshold value.

However, ER waves may be affected by intrinsic ventricular activation (including atrioventricular conduction intrinsic ventricular activation and ventricular premature PVC) and may cause erroneous determination of the beat-by-beat monitoring function. Therefore, the ventricular pacing beat-to-beat monitoring function is more complicated in practical applications than the above-described procedure. The existing ventricular pacing beat-to-beat monitoring schemes are different, but have certain commonality, namely fusion wave elimination is carried out by a method of prolonging or reducing AV interval, which is specifically as follows: and acquiring ER waves, judging capture or loss of capture, immediately sending a standby pulse after finding out loss of capture, and operating a fusion wave elimination algorithm. The existing various fusion wave elimination algorithms are slightly different: if the AV interval is prolonged by 100ms, if the loss of capture is continuously monitored for two times again, the AV interval is recovered, pulses are issued according to standard voltage, and finally threshold search is started; if the AV interval is prolonged by 64ms and 2 times of loss of capture occur in 4 cardiac cycles, threshold search is started; and the AV interval is prolonged by 65ms, the capture state of the Vp at the moment is monitored, if the fusion wave cannot be eliminated, the AV interval is reduced (the SAV interval is 15ms, the PAV interval is 50ms), the capture state of the Vp at the moment is monitored, and when two times of loss of capture are monitored, threshold search is started. The prior art ventricular pacing beat-to-beat monitoring has the following characteristics: when one-time loss of capture occurs, fused wave elimination is carried out, specifically, the AV interval is prolonged or shortened, the capture state of the ER wave after the Vp is collected for multiple times is judged, and finally whether threshold search is started or not is determined.

In the prior art, the energy of the central chamber pacing pulse Vp is higher than a ventricular pacing threshold value, which is a precondition for ensuring effective ventricular pacing. However, when the ER waveform state collected by the pacemaker is affected by intrinsic ventricular activation, the algorithm may determine that capture is lost even if the energy of Vp is higher than the ventricular pacing threshold; conversely, Vp has an energy below the ventricular pacing threshold, but may be determined by the algorithm to capture. The energy of the ventricular backup pacing pulse vp (b) is also above the ventricular pacing threshold, however vp (b) may also be affected by intrinsic ventricular activation and is determined by the algorithm to be loss of capture; alternatively, if vp (b) is in the ventricular refractory period, it is also determined by the algorithm to be lost of capture. Therefore, the accuracy of the ventricular pacing beat-to-beat monitoring method in the prior art is relatively low, the ventricular pulse energy cannot be output accurately and reasonably, and the fusion wave algorithm is easily misjudged by the excitation interference of the ventricle of the user.

Disclosure of Invention

The application provides a beat-to-beat monitoring system and method for an implanted cardiac pacemaker, which aim to solve the problems that the accuracy of a heart chamber pacing beat-to-beat monitoring method in the prior art is relatively low, the ventricular pulse energy cannot be accurately and reasonably output, and a fusion wave algorithm is easily misjudged by the excitation interference of the ventricle of the user.

The technical scheme adopted by the application is as follows:

a beat-to-beat monitoring system for an implantable cardiac pacemaker comprises a ventricular pacing circuit unit 100, a beat-to-beat monitoring unit 200, a standby pulse monitoring unit 300 and a ventricular threshold searching unit 400;

the ventricular pacing circuit unit 100 is electrically connected to the beat-to-beat monitoring unit 200, and is configured to deliver ventricular pacing pulses;

the beat-to-beat monitoring unit 200 is electrically connected to the standby pulse monitoring unit 300, and is configured to collect an ER wave generated by the ventricular pacing pulse Vp, compare a digital signal formed after filtering, amplifying, and converting the ER wave with a reference standard thereof, and determine and output a capture/loss state of the ventricular pacing pulse Vp;

the standby pulse monitoring unit 300 is electrically connected to the ventricular pacing circuit unit 100, and is configured to trigger the ventricular pacing circuit unit 100 to issue a ventricular standby pulse Vp (b) when the beat-to-beat monitoring unit 200 identifies that the output state is loss of capture, and the time interval after the ventricular pacing pulse Vp is issued is T, acquire an ER wave generated by the ventricular standby pulse Vp (b), compare a digital signal formed after the ER wave is filtered, amplified and converted with a reference standard thereof, determine and output the capture/loss state of the ventricular standby pulse Vp (b), and set and prolong an AV interval of the ventricular pacing circuit unit 100 when the standby pulse monitoring unit 300 identifies that the output state is loss of capture;

the ventricular threshold search unit 400 is electrically connected to the standby pulse monitoring unit 300, and is configured to trigger the ventricular threshold search unit 400 to start working when the standby pulse monitoring unit 300 recognizes that the output state is capture, obtain a current ventricular pacing threshold, and reset ventricular pacing output energy.

Preferably, the hop-by-hop monitoring unit 200 includes a first timer 201, an ER wave processing unit for Vp, a first capture/loss recognition unit;

the input end of the first timer 201 is electrically connected with the ventricular pacing circuit unit 100, and is used for limiting the timing start point and the timing end point of the ER wave collected after the ventricular pacing pulse;

the output end of the first timer 201 is electrically connected to the ER wave processing unit of Vp, and is configured to sequentially perform filtering, amplification and AD conversion on the ER wave generated after the ventricular pacing circuit unit 100 delivers the ventricular pacing pulse, so as to form a digital signal of the ER wave generated by Vp;

the input end of the first capture/loss capture identification unit is electrically connected with the ER wave processing unit of the Vp, and is used for comparing a digital signal formed by processing the ER wave of the Vp with a reference standard thereof, and judging and outputting the capture/loss capture state of the current ventricular pacing pulse Vp;

the output end of the first capture/loss capture identification unit is electrically connected to the standby pulse monitoring unit 300, and is configured to trigger the ventricular pacing circuit unit 100 to deliver a ventricular standby pulse Vp (b) when the time interval after the delivery of the ventricular pacing pulse Vp is T when the first capture/loss capture identification unit determines that the output state is loss of capture.

Preferably, the ER wave processing unit of Vp includes a first filter 202, a first amplifier 203, a first AD converter 204;

the output end of the first timer 201 is electrically connected to the first filter 202, the first amplifier 203 and the first AD converter 204 in sequence, and is configured to sequentially perform filtering, amplification and AD conversion processes on the ER wave generated after the ventricular pacing circuit unit 100 delivers the ventricular pacing pulse through the first filter 202, the first amplifier 203 and the first AD converter 204, so as to form a digital signal of the ER wave generated by Vp.

Preferably, the first capture/loss identification unit comprises a first register 205 and a first comparator 206;

the first register 205 and the first AD converter 204 are both electrically connected to the input of the first comparator 206, the first register 205 is used for storing a reference standard for capturing an ER wave of a ventricle;

the output end of the first comparator 206 is electrically connected to the standby pulse monitoring unit 300, and is configured to compare the digital signal formed by processing the ER wave of the ventricular pacing pulse with the reference standard in the first register 205, and determine and output the capture/loss capture state of the ventricular pacing pulse Vp.

Preferably, the spare pulse monitoring unit 300 includes a second timer 301, an ER wave processing unit of vp (b), a second capture/loss capture identification unit, a third timer 307, a fourth timer 308;

the input end of the third timer 307 is electrically connected to the first comparator 206, the output end of the third timer 307 is electrically connected to the ventricular pacing circuit unit 100, and the third timer 307 is configured to trigger the ventricular pacing circuit unit 100 to deliver a ventricular standby pulse Vp (b) when the time interval after the delivery of the ventricular pacing pulse Vp is T when the first comparator 206 identifies that the output state is loss of capture;

the input end of the second timer 301 is electrically connected to the ventricular pacing circuit unit 100, and is used for defining the acquisition timing start point and the timing end point of the ER wave generated by the ventricular standby pulse vp (b);

the output end of the second timer 301 is electrically connected to the ER wave processing unit of vp (b), and is used for filtering, amplifying and AD converting the ER wave generated by the ventricular standby pulse vp (b) to form a digital signal of the ER wave generated by vp (b);

the input end of the second capture/loss capture identification unit is electrically connected with the ER wave processing unit of Vp (B) and is used for comparing the digital signal of the ER wave generated by the ventricular standby pulse Vp (B) with a reference standard thereof and judging and outputting the capture/loss capture state of the ventricular standby pulse Vp (B);

the output end of the second capture/loss capture identification unit is electrically connected to the fourth timer 308 and the ventricular threshold search unit 400, and is configured to trigger the ventricular threshold search unit 400 to start working when the second capture/loss capture identification unit identifies that the output state is capture, obtain the current ventricular pacing threshold, and reset ventricular pacing output energy;

the output terminal of the fourth timer 308 is electrically connected to the ventricular pacing circuit unit 100, and is configured to set an AV interval for extending the ventricular pacing circuit unit 100 when the second capture/loss recognition unit recognizes that the output status is loss of capture.

Preferably, the ER wave processing unit of vp (b) includes a second filter 302, a second amplifier 303, a second AD converter 304;

the output end of the second timer 301 is electrically connected to the second filter 302, the second amplifier 303 and the second AD converter 304 in sequence, and is configured to pass the ER wave generated by the ventricular standby pulse vp (b) through the filtering, amplifying and AD converting processes of the second filter 302, the second amplifier 303 and the second AD converter 304, so as to form a digital signal of the ER wave generated by vp (b).

Preferably, the second capture/loss identification unit includes a second register 305 and a second comparator 306;

the second register 305 and the second AD converter 304 are both electrically connected to the input of the second comparator 306, the second register 305 is used for storing a reference standard for capturing the ER wave of the ventricle;

the output end of the second comparator 306 is electrically connected to the fourth timer 308 and the ventricular threshold search unit 400, and is configured to trigger the ventricular threshold search unit 400 to start working when the second comparator 306 identifies that the output state is capture, obtain the current ventricular pacing threshold, and set ventricular pacing output at the same time.

A beat-to-beat monitoring method for an implantable cardiac pacemaker is applied to the beat-to-beat monitoring system for the implantable cardiac pacemaker, and comprises the following steps:

the ventricular pacing circuit unit 100 delivers ventricular pacing pulses;

the beat-to-beat monitoring unit 200 collects ER waves generated by ventricular pacing pulses Vp in a set time interval;

comparing a digital signal formed by filtering, amplifying and converting the ER wave generated by Vp with a reference standard thereof, and judging and outputting the capture/loss state of the ventricular pacing pulse Vp;

when the output state of the skip-by-skip monitoring unit 200 is capture, the standby pulse monitoring unit 300 is inhibited, and the pacemaker does not perform other operations;

when the output state of the beat-to-beat monitoring unit 200 is loss of capture, triggering the ventricular pacing circuit unit 100 to deliver a ventricular standby pulse Vp (b) when the time interval is T after delivering the ventricular pacing pulse Vp;

triggering the standby pulse monitoring unit 300 to collect ER waves generated by ventricular standby pulses Vp (B) in a set time interval;

comparing a digital signal formed by filtering, amplifying and converting ER waves generated by Vp (B) with a reference standard thereof, and judging and outputting the capture/loss capture state of ventricular standby pulses Vp (B);

when the output state of the ventricular standby pulse vp (b) is judged to be capture, triggering the ventricular threshold search unit 400 to start working, obtaining the current ventricular pacing threshold, and resetting ventricular pacing output energy;

when the output status of the ventricular backup pulse vp (b) is determined to be loss of capture, an AV interval that extends the ventricular pacing circuit unit 100 is set for encouraging self-ventricular activation.

Preferably, the setting of the AV interval for extending the ventricular pacing circuit unit 100 when the output status of the ventricular standby pulse vp (b) is determined to be loss of capture includes:

the extended AV interval is original AV interval + T + δ, where T is the time interval that triggers the ventricular pacing circuit unit 100 to deliver a ventricular backup pulse Vp (b) after delivering a ventricular pacing pulse Vp when the beat-by-beat monitoring unit 200 identifies the output state as loss of capture; delta is the fluctuation value of the intrinsic ventricular activation.

Preferably, the ER wave acquisition time interval of Vp (b) is delayed from the ER wave acquisition time interval of Vp.

The technical scheme of the application has the following beneficial effects:

1. the ventricular pacing beat-to-beat monitoring method is simplified, and unnecessary lengthening or shortening of the AV interval is avoided.

2. Loss of capture is identified more quickly and a ventricular threshold search is initiated, thereby ensuring effectiveness of pacemaker operation.

3. Intrinsic ventricular activation is detected more quickly and the AV interval is extended to encourage intrinsic ventricular activation while reducing the number of delivery of backup pulses, thereby conserving pacemaker power.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a beat-to-beat monitoring system for an implantable cardiac pacemaker according to the present application;

FIG. 2 is a flow chart of a monitoring method of a beat-to-beat monitoring system for an implantable cardiac pacemaker according to the present application;

FIG. 3 is a schematic diagram of ventricular pacing pulses Vp and ER wave acquisition windows thereof for ventricular pacing beat-to-beat monitoring in accordance with the present application;

FIG. 4 is a schematic diagram of ventricular standby pulses Vp (B) and their ER wave acquisition windows for ventricular pacing beat-to-beat monitoring in accordance with the present application;

FIG. 5 is a logic diagram of various situations in which Vp and Vp (B) are determined by the algorithm to be either capturing or losing capture according to the present application;

FIG. 6 is a flow chart of a specific monitoring process for ventricular pacing step-by-step in accordance with the present application;

illustration of the drawings:

the device comprises a 100-ventricular pacing circuit unit, a 200-beat-by-beat monitoring unit, a 201-first timer, a 202-first filter, a 203-first amplifier, a 204-first AD converter, a 205-first register, a 206-first comparator, a 300-standby pulse monitoring unit, a 301-second timer, a 302-second filter, a 303-second amplifier, a 304-second AD converter, a 305-second register, a 306-second comparator, a 307-third timer, a 308-fourth timer and a 400-ventricular threshold searching unit.

Detailed Description

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following examples do not represent all embodiments consistent with the present application. But merely as exemplifications of systems and methods consistent with certain aspects of the application, as recited in the claims.

Referring to fig. 1, a schematic diagram of a beat-to-beat monitoring system for an implantable cardiac pacemaker according to the present application is shown.

Abbreviations in the text of this application are explained as follows:

as: atrial sensing;

ap: atrial pacing pulses;

vs: ventricular sensing, an atrioventricular conducted intrinsic ventricular activation;

PVC: ventricular premature beat, a self ventricular activation that is generated in advance at ectopic pacing points below the bundle of his branches;

vp: ventricular pacing pulses;

vp (B): ventricular backup pacing pulses;

AV: an atrioventricular interval;

SAV: atrial sensed AV interval;

PAV: an atrial paced AV interval;

ER wave: the depolarization wave generated after the ventricular pacing pulse is used for judging capture and loss of capture.

The application provides a beat-to-beat monitoring system for an implantable cardiac pacemaker, which comprises a ventricular pacing circuit unit 100, a beat-to-beat monitoring unit 200, a standby pulse monitoring unit 300 and a ventricular threshold searching unit 400;

As shown in fig. 1, the hop-by-hop monitoring unit 200 includes a first timer 201, an ER wave processing unit for Vp, and a first capture/loss recognition unit;

The ER wave processing unit of Vp comprises a first filter 202, a first amplifier 203 and a first AD converter 204;

The first capture/loss of capture identification unit comprises a first register 205 and a first comparator 206;

The standby pulse monitoring unit 300 includes a second timer 301, an ER wave processing unit of vp (b), a second capture/loss capture identification unit, a third timer 307, and a fourth timer 308;

The ER wave processing unit of Vp (B) comprises a second filter 302, a second amplifier 303 and a second AD converter 304;

The second capture/loss of capture identification unit includes a second register 305 and a second comparator 306;

As shown in fig. 2 and fig. 6, a beat-to-beat monitoring method for an implantable cardiac pacemaker is applied to the beat-to-beat monitoring system for the implantable cardiac pacemaker, and includes the following steps:

the ventricular pacing circuit unit 100 delivers ventricular pacing pulses;

When the output state of the ventricular standby pulse vp (b) is determined to be loss of capture, the setting of the AV interval of the ventricular pacing circuit unit 100 is extended, including:

The ER wave acquisition time interval of the Vp (B) is delayed from the ER wave acquisition time interval of the Vp.

The feasibility of the solution of the present application is elucidated below.

FIG. 3 is a schematic diagram of a ventricular pacing pulse Vp and its ER wave acquisition window for ventricular pacing beat-to-beat monitoring, where the acquisition window is the acquisition time interval and is marked as t when the pacemaker delivers the ventricular pacing pulse Vp₀At the moment, the acquisition window of the ER wave is t₁To t₂：

Δt＝t₂-t₁，

Wherein, the timing start point t₁5 ms-30 ms can be selected, the step length is 5ms, and the default value is 10 ms; end of timing t₂The method can select 65 ms-80 ms, the step length is 5ms, and the default value is 70 ms.

When the output of the first comparator 206 results in capture, there are three possibilities:

firstly, the output energy of Vp is not lower than the ventricular pacing threshold, and the algorithm correctly judges that Vp captures the ventricle;

secondly, the output energy of Vp is not lower than the ventricular pacing threshold, but the Vp and the self ventricle are excited to generate a fusion wave, so that the acquired ER waveform state is interfered to a certain degree, and yet the algorithm can still correctly judge Vp capture;

thirdly, the output energy of Vp is lower than the ventricular pacing threshold, but Vp and self ventricular activation generate a false fusion wave, so that the acquired ER waveform state is interfered to a certain degree, and the algorithm wrongly judges Vp capture.

In the third case, it can be seen that Vp output energy is below the ventricular pacing threshold and may be determined by the algorithm to capture. Such a false positive may be considered safe because of the presence of intrinsic ventricular activation.

When the output of the first comparator 206 results in loss of capture, there are also three possibilities:

firstly, the output energy of Vp is lower than the ventricular pacing threshold, and the algorithm correctly judges that Vp loses capture;

secondly, the output energy of Vp is not lower than the ventricular pacing threshold, but the Vp and the self ventricle are excited to generate fusion waves, so that the waveform state of the acquired ER waveform is interfered to a certain degree, and the algorithm wrongly judges that Vp is lost;

third, the output energy of Vp is lower than the ventricular pacing threshold, and Vp and intrinsic ventricular activation generate a false fusion wave, which causes the acquired ER waveform to be disturbed to some extent, but the algorithm can still correctly determine that Vp is lost from capture.

For all three situations, whichever results in Vp being determined by the algorithm to be lost, the pacemaker will deliver a ventricular backup pulse Vp (b) to ensure the safety of pacemaker operation.

FIG. 4 is a schematic diagram of ventricular standby pulses Vp (B) and their ER wave acquisition windows for ventricular pacing beat-to-beat monitoring at t₂At the moment, when the ventricular pacing pulse Vp (b) delivered by the pacemaker is determined to lose capture, the third timer 307 is started, so that the ventricular pacing circuit unit 100 delivers a ventricular standby pulse Vp (b) after T ms of the ventricular pacing pulse Vp, T can be selected from 90ms to 120ms, the step length is 5ms, and the default value is 100 ms;

when the ventricular standby pulse Vp (B) is released, the time is recorded as t3, and the acquisition window of the ER wave is t₄To t₅：

Δt'＝t₅-t₄，

Wherein, the timing start point t₄5 ms-30 ms can be selected, the step length is 5ms, and the default value is 20 ms; end of timing t₅The method can select 65 ms-80 ms, the step length is 5ms, and the default value is 80 ms.

It can be seen that the ER wave acquisition window of the ventricular backup pulse Vp (b) is delayed by 10ms compared with the default value of the ER wave acquisition window of the ventricular pacing pulse Vp because Vp (b) has high energy and produces a large polarization potential, and therefore, in order to improve the accuracy of the algorithm, a relatively delayed ER wave acquisition window is generally set for the ventricular backup pulse Vp (b).

When the output of the second comparator 306 results in capture, there are two possibilities:

first, vp (b) is not disturbed by intrinsic ventricular activation, and the algorithm correctly determines vp (b) capture;

second, vp (b) is disturbed to some extent by intrinsic ventricular activation, but the algorithm still correctly determines vp (b) capture;

both of the above situations indicate that the output energy of the ventricular pacing pulse Vp is below the ventricular pacing threshold. Because, conversely, if the output energy of Vp is not lower than the ventricular pacing threshold, Vp (b) is inevitably in the ventricular refractory period regardless of whether Vp is interfered by the fusion wave, and is determined by the algorithm to be lack of capture, which contradicts the output result of the second comparator 306. Therefore, when the output of the second comparator 306 is capture, it is necessary to immediately initiate a ventricular threshold search and reset a reasonable ventricular pacing output energy.

When the output of the second comparator 306 results in loss of capture, there are two possibilities:

first, vp (b) is disturbed by intrinsic ventricular activation, resulting in the algorithm erroneously determining that vp (b) is lost of capture;

second, vp (b) is not disturbed by intrinsic ventricular activation, but is in the ventricular refractory period, resulting in the algorithm deciding that vp (b) is lost of capture.

Both of these situations indicate the presence of intrinsic ventricular activation. The intrinsic ventricular activation forms a fusion wave with either Vp (b) or Vp (b), and only in these cases Vp and Vp (b) are both determined by the algorithm to be lost. Therefore, when the output of the comparator 306 is loss of capture, the timer 308 should extend the AV interval to encourage ventricular activation.

The extended AV interval is the original AV interval + T + delta,

wherein δ is a fluctuating value of the intrinsic ventricular activation, which can be selected to be 10 ms-50 ms, and a default value of 30ms, and is set to encourage an intrinsic ventricular activation event slightly later than the ventricular standby pulse vp (b).

In order to more clearly exhibit the various situations in which Vp and Vp (b) are determined by the algorithm to be either capture or loss of capture, fig. 5 shows their detailed logical relationships.

In fig. 5, Vp is determined by the algorithm to contain three situations for each of capture and loss of capture; vp (b) is determined by the algorithm to be in two situations, capture and loss of capture, respectively, Vp is determined by the algorithm to be in loss of capture as the cause of triggering the hop-by-hop monitoring function.

For case 4, in which Vp is determined by the algorithm to be lost of capture, generally, Vp (b) is delivered thereafter, which is determined by the algorithm to be captured to include cases 7 and 8, and a ventricular threshold search is initiated; however, if vp (b) forms a fusion wave with intrinsic ventricular activation and has a large impact on the acquired ER waveform state, vp (b) may be determined by the algorithm to be loss of capture, i.e., case 9. At this point, the pacemaker will extend the AV interval, encouraging intrinsic ventricular activation;

for cases 5 and 6, where Vp is determined by the algorithm to be lost of capture, Vp (b) is in the ventricular refractory period due to the presence of intrinsic ventricular activation. Thus, vp (b) cannot capture the ventricle and is determined by the algorithm to be lost of capture, case 10. At this point, the pacemaker will extend the AV interval, encouraging intrinsic ventricular activation;

for case 1 where Vp is determined by the algorithm to be captured, the output energy of Vp is not lower than the ventricular pacing threshold, and there is no interference from self ventricular activation, then no operation of the beat-by-beat monitoring function is triggered (neither ventricular threshold search is initiated nor AV interval is extended);

for cases 2 and 3 in which Vp is determined by the algorithm to be captured, the ER wave corresponding to each generated fusion wave or false fusion wave is morphologically different due to the uncertainty of the activation morphology of the ventricle itself and the uncertainty of the occurrence time. Thus, when a fusion wave or a spurious fusion wave is generated, the acquired ER wave may be judged by the algorithm to be either capture or loss of capture. That is, when fusion waves or false fusion waves occur continuously, the decision result of the algorithm necessarily translates into loss of capture, i.e., from case 2 to case 6, and from case 3 to case 5, thereby causing the pacemaker to extend the AV interval, encouraging self-ventricular activation.

The traditional method prolongs the AV interval in order to eliminate fusion waves, namely acquiring ER waves of ventricular pacing pulses Vp which are delivered in a delayed manner, and judging capture and loss of capture; the present application extends the AV interval to encourage intrinsic ventricular activation.

In summary, when Vp is determined by the algorithm to be loss of capture and the presence of intrinsic ventricular activation is not detected, the pacemaker will initiate a ventricular threshold search; when the presence of ventricular activation is detected (whether Vp is determined by the algorithm to be captured or not), the pacemaker preferentially extends the AV interval, encouraging ventricular activation.

As shown in fig. 6, a situation where Vp is determined by the algorithm to be captured: after the ventricular pacing circuit unit 100 delivers Vp, the first timer 201 collects ER waves within a set time, the ER waves are processed by the first filter 202, the first amplifier 203 and the first AD converter 204 to form Vp digital signals, and the Vp digital signals are compared with the reference standard stored in the first register 205, and the first comparator 206 outputs Vp, so that the Vp is captured. At this point, backup pulse monitoring unit 300 will be inhibited and the pacemaker will not perform other operations.

Vp is determined by the algorithm to be lost capture, Vp (b) is determined by the algorithm to be capture: when the first comparator 206 outputs Vp and the determination result is loss of capture, the standby pulse monitoring unit 300 is triggered, the third timer 307 is started, and the ventricular pacing circuit unit 100 is triggered to deliver a ventricular standby pulse Vp (b) after Tms of Vp; the second timer 301 collects ER waves vp (b) within a set time, the ER waves vp (b) are processed by the second filter 302, the second amplifier 303 and the second AD converter 304 to form vp (b) digital signals, the vp (b) digital signals are compared with reference standards stored in the second register 305, and the second comparator 306 outputs vp (b) digital signals to determine that capture is achieved, at this time, the threshold search unit 400 is triggered, the pacemaker obtains a current ventricular pacing threshold, and a reasonable ventricular pacing output quantity is set.

Vp and Vp (b) are both determined by the algorithm to be loss of capture: the standby pulse monitoring unit 300 will be triggered when the determination result of Vp output by the first comparator 206 is loss of capture, and the determination result of Vp (b) output by the second comparator 306 is also loss of capture, and the fourth timer 308 will be triggered when the determination result of Vp (b) output by the second comparator is loss of capture, so as to set an extended AV interval and act on the ventricular pacing circuit unit 100, thereby achieving the purpose of encouraging self-ventricular activation.

By collecting ER waves of Vp and Vp (B), a new fusion wave elimination method is designed, and ventricular threshold search is started when needed, so that reasonable ventricular output pulse energy is set. Compared with the traditional method, the method has the following advantages on the premise of ensuring the working reliability of the pacemaker:

firstly, the ventricular pacing beat-to-beat monitoring method is simplified, and unnecessary lengthening or shortening of the AV interval is avoided;

secondly, loss of capture is identified more quickly, and ventricular threshold search is started, so that the working effectiveness of the pacemaker is guaranteed;

third, intrinsic ventricular activation is detected more quickly, and the AV interval is extended to encourage intrinsic ventricular activation, while the number of delivery of backup pulses is reduced, thereby conserving pacemaker power.

The embodiments provided in the present application are only a few examples of the general concept of the present application, and do not limit the scope of the present application. Any other embodiments extended according to the scheme of the present application without inventive efforts will be within the scope of protection of the present application for a person skilled in the art.

Claims

1. A beat-to-beat monitoring system for an implantable cardiac pacemaker, comprising a ventricular pacing circuit unit (100), a beat-to-beat monitoring unit (200), a standby pulse monitoring unit (300) and a ventricular threshold search unit (400);

the ventricular pacing circuit unit (100) is electrically connected with the beat-to-beat monitoring unit (200) and used for delivering ventricular pacing pulses;

the beat-to-beat monitoring unit (200) is electrically connected with the standby pulse monitoring unit (300) and is used for collecting ER waves generated by the ventricular pacing pulses Vp, comparing digital signals formed by filtering, amplifying and converting the ER waves with reference standards thereof, and judging and outputting the capture/loss capture states of the ventricular pacing pulses Vp;

the standby pulse monitoring unit (300) is electrically connected with the ventricular pacing circuit unit (100) and is used for triggering the ventricular pacing circuit unit (100) to deliver a ventricular standby pulse Vp (B) when the beat-by-beat monitoring unit (200) identifies that the output state is loss of capture, the time interval after the ventricular pacing pulse Vp is delivered is T, the ER wave generated by the ventricular standby pulse Vp (B) is collected, a digital signal formed by filtering, amplifying and converting the ER wave is compared with a reference standard, the capture/loss capture state of the ventricular standby pulse Vp (B) is judged and output, and when the standby pulse monitoring unit (300) identifies that the output state is loss of capture, the AV interval of the ventricular pacing circuit unit (100) is prolonged;

the ventricular threshold searching unit (400) is electrically connected with the standby pulse monitoring unit (300) and is used for triggering the ventricular threshold searching unit (400) to start working when the standby pulse monitoring unit (300) identifies that the output state is capture, obtaining the current ventricular pacing threshold and resetting ventricular pacing output energy.

2. The beat-to-beat monitoring system for an implantable cardiac pacemaker as claimed in claim 1, wherein the beat-to-beat monitoring unit (200) comprises a first timer (201), an ER wave processing unit for Vp, a first capture/loss capture identification unit;

the input end of the first timer (201) is electrically connected with the ventricular pacing circuit unit (100) and is used for limiting the timing starting point and the timing end point of ER wave acquisition after ventricular pacing pulse;

the output end of the first timer (201) is electrically connected with the ER wave processing unit of Vp and is used for sequentially carrying out filtering, amplification and AD conversion processing on ER waves generated after the ventricular pacing circuit unit (100) delivers ventricular pacing pulses to form digital signals of the ER waves generated by Vp;

the output end of the first capture/loss capture identification unit is electrically connected with a standby pulse monitoring unit (300) and is used for triggering the ventricular pacing circuit unit (100) to deliver a ventricular standby pulse Vp (B) when the time interval after the delivery of the ventricular pacing pulse Vp is T when the first capture/loss capture identification unit judges that the output state is loss of capture.

3. The hop-by-hop monitoring system for an implantable cardiac pacemaker as claimed in claim 2, wherein the Vp ER wave processing unit comprises a first filter (202), a first amplifier (203), a first AD converter (204);

the output end of the first timer (201) is electrically connected with the first filter (202), the first amplifier (203) and the first AD converter (204) in sequence, and is used for enabling ER waves generated after ventricular pacing pulses are delivered by the ventricular pacing circuit unit (100) to sequentially pass through filtering, amplifying and AD converting processes of the first filter (202), the first amplifier (203) and the first AD converter (204) to form digital signals of the ER waves generated by Vp.

4. A beat-to-beat monitoring system for an implantable cardiac pacemaker as described in claim 3, wherein the first capture/loss capture identification unit comprises a first register (205) and a first comparator (206);

the first register (205) and the first AD converter (204) are electrically connected with the input end of the first comparator (206), and the first register (205) is used for storing a reference standard for capturing an ER wave of a ventricle;

the output end of the first comparator (206) is electrically connected with a standby pulse monitoring unit (300) and is used for comparing a digital signal formed by processing an ER wave of a ventricular pacing pulse with a reference standard in the first register (205) and judging and outputting the capture/loss capture state of the ventricular pacing pulse Vp.

5. The beat-to-beat monitoring system for an implantable cardiac pacemaker as described in claim 4, wherein the back-up pulse monitoring unit (300) comprises a second timer (301), an ER wave processing unit for Vp (B), a second capture/loss capture identification unit, a third timer (307), a fourth timer (308);

the input end of the third timer (307) is electrically connected with the first comparator (206), the output end of the third timer (307) is electrically connected with the ventricular pacing circuit unit (100), and the third timer (307) is used for triggering the ventricular pacing circuit unit (100) to deliver a ventricular standby pulse Vp (B) when the time interval is T after the ventricular pacing pulse Vp is delivered when the first comparator (206) identifies that the output state is loss of capture;

the input end of the second timer (301) is electrically connected with the ventricular pacing circuit unit (100) and is used for limiting the acquisition timing starting point and the timing end point of the ER wave generated by the ventricular standby pulse Vp (B);

the output end of the second timer (301) is electrically connected with the ER wave processing unit of Vp (B) and is used for processing the ER wave generated by the ventricular standby pulse Vp (B) through filtering, amplification and AD conversion to form a digital signal of the ER wave generated by Vp (B);

the output end of the second capture/loss capture identification unit is electrically connected with the fourth timer (308) and the ventricular threshold search unit (400), and is used for triggering the ventricular threshold search unit (400) to start working when the second capture/loss capture identification unit identifies that the output state is capture, obtaining the current ventricular pacing threshold, and resetting ventricular pacing output energy;

the output end of the fourth timer (308) is electrically connected with the ventricular pacing circuit unit (100) and is used for setting and prolonging the AV interval of the ventricular pacing circuit unit (100) when the second capture/loss recognition unit recognizes that the output state is loss of capture.

6. The hop-by-hop monitoring system for an implantable cardiac pacemaker as claimed in claim 5, wherein the ER wave processing unit of Vp (B) comprises a second filter (302), a second amplifier (303), a second AD converter (304);

the output end of the second timer (301) is electrically connected to the second filter (302), the second amplifier (303) and the second AD converter (304) in sequence, and is used for passing the ER wave generated by the ventricular standby pulse vp (b) through the filtering, amplifying and AD converting processes of the second filter (302), the second amplifier (303) and the second AD converter (304) to form a digital signal of the ER wave generated by vp (b).

7. The beat-to-beat monitoring system for an implantable cardiac pacemaker as described in claim 6, wherein the second capture/loss capture identification unit comprises a second register (305) and a second comparator (306);

the second register (305) and the second AD converter (304) are electrically connected with the input end of the second comparator (306), and the second register (305) is used for storing a reference standard for capturing the ER wave of the ventricle;

the output end of the second comparator (306) is electrically connected with the fourth timer (308) and the ventricular threshold search unit (400), and is used for triggering the ventricular threshold search unit (400) to start working when the second comparator (306) identifies that the output state is capture, obtaining the current ventricular pacing threshold, and simultaneously setting ventricular pacing output.

8. A beat-to-beat monitoring method for an implantable cardiac pacemaker, applied to the beat-to-beat monitoring system for the implantable cardiac pacemaker according to any one of claims 1 to 7, comprising the steps of:

the ventricular pacing circuit unit (100) delivers ventricular pacing pulses;

the beat-to-beat monitoring unit (200) collects ER waves generated by ventricular pacing pulses Vp in a set time interval;

when the output state of the beat-to-beat monitoring unit (200) is capture, the standby pulse monitoring unit (300) is inhibited, and the pacemaker does not perform other operations;

when the output state of the beat-to-beat monitoring unit (200) is loss of capture, triggering the ventricular pacing circuit unit (100) to deliver a ventricular standby pulse Vp (B) when the time interval is T after delivering the ventricular pacing pulse Vp;

triggering the standby pulse monitoring unit (300) to collect ER waves generated by ventricular standby pulses Vp (B) in a set time interval;

when the output state of the ventricular standby pulse Vp (B) is judged to be capture, triggering a ventricular threshold search unit (400) to start working, obtaining a current ventricular pacing threshold, and resetting ventricular pacing output energy;

setting an AV interval that extends the ventricular pacing circuit unit (100) for encouraging intrinsic ventricular activation when the output status of the ventricular backup pulse Vp (B) is determined to be loss of capture.

9. The beat-to-beat monitoring method for an implantable cardiac pacemaker as claimed in claim 8, wherein the setting of the extended AV interval of the ventricular pacing circuit unit (100) when the output state of the ventricular standby pulse Vp (B) is determined to be loss of capture comprises:

the extended AV interval is a raw AV interval + T + δ, where T is a time interval that triggers the ventricular pacing circuit unit (100) to deliver a ventricular backup pulse Vp (B) after delivering a ventricular pacing pulse Vp when the beat-by-beat monitoring unit (200) recognizes the output state as loss of capture; delta is the fluctuation value of the intrinsic ventricular activation.

10. The beat-to-beat monitoring method of claim 8, wherein the ER wave acquisition time interval of Vp (b) is delayed from the ER wave acquisition time interval of Vp.