WCD system validating detected cardiac arrhythmias thoroughly so as to not sound loudly due to some quickly self-terminating cardiac arrhythmias

A wearable cardioverter defibrillator (“WCD”) system may output a loud sound after detecting and validating a shockable cardiac arrhythmia. In such embodiments, however, the WCD system might not sound a loud alarm before validating the arrhythmia thoroughly, i.e. for a longer time, thus giving the arrhythmia a further chance to self-terminate. The WCD system may thus detect more robustly the cardiac arrhythmias that do not self-terminate quickly. Such arrhythmias that self-terminate quickly may occur from likely harmless events occurring multiple times in the daily life of the patient, such as the patient becoming “winded” from climbing stairs. In embodiments the WCD system may notify the patient only discreetly, or even not at all. The lack of sounding such a loud alarm responsive to such events reduces the overall number of times in which the patient experiences unwanted attention by others, embarrassment, loss of privacy and dignity, and so on.

BACKGROUND

When people suffer from some types of heart arrhythmias, the result may be that blood flow to various parts of the body is reduced. Some arrhythmias may even result in a sudden cardiac arrest (SCA). SCA can lead to death very quickly, e.g. within 10 minutes, unless treated in the interim.

Some people have an increased risk of SCA. People at a higher risk include patients who have had a heart attack, or a prior SCA episode. A frequent recommendation is for these people to receive an implantable cardioverter defibrillator (“ICD”). The ICD is surgically implanted in the chest, and continuously monitors the patient's electrocardiogram (“ECG”). If certain types of heart arrhythmias are detected, then the ICD delivers an electric shock through the heart.

After being identified as having an increased risk of an SCA, and before receiving an ICD, these people are sometimes given a wearable cardioverter defibrillator (“WCD”) system. (Earlier versions of such systems were called wearable cardiac defibrillator systems.) A WCD system typically includes a harness, vest, or other garment that the patient is to wear. The WCD system includes a defibrillator and electrodes, coupled to the harness, vest, or other garment. When the patient wears the WCD system, the external electrodes may then make good electrical contact with the patient's skin, and therefore can help determine the patient's ECG. If a shockable heart arrhythmia is detected, then the defibrillator delivers the appropriate electric shock through the patient's body, and thus through the heart.

BRIEF SUMMARY

The present description gives instances of wearable cardioverter defibrillator (“WCD”) systems, storage media that store programs, and methods, the use of which may help overcome problems and limitations of the prior art.

In some embodiments, a wearable cardioverter defibrillator (“WCD”) system may output a loud sound after detecting and validating a shockable cardiac arrhythmia. In such embodiments, however, the WCD system might not sound a loud alarm before validating the arrhythmia thoroughly, i.e. for a longer time, thus giving the arrhythmia a further chance to self-terminate. As such, the WCD system may detect more robustly the cardiac arrhythmias that do not self-terminate quickly.

In some embodiments, a wearable cardioverter defibrillator (“WCD”) system may output a loud sound after detecting and validating a shockable cardiac arrhythmia. If the cardiac arrhythmia self-terminates relatively quickly, however, the WCD system might transmit data from the cardiac arrhythmia for analysis, without sounding loudly due to the cardiac arrhythmia.

In some embodiments, a wearable cardioverter defibrillator (“WCD”) system may output a loud sound after detecting and validating a shockable cardiac arrhythmia. If the cardiac arrhythmia self-terminates relatively quickly, however, the WCD system might store data from the cardiac arrhythmia for later analysis, without sounding loudly due to the cardiac arrhythmia.

In some embodiments, a wearable cardioverter defibrillator (“WCD”) system may output an audible sound after detecting and validating a shockable cardiac arrhythmia. Before validating, however, the WCD system may wait discreetly for the detected cardiac arrhythmia to self-terminate relatively quickly, without outputting such a sound until then.

In some embodiments, a wearable cardioverter defibrillator (“WCD”) system may output a loud sound after detecting and validating a shockable cardiac arrhythmia. Before validating, however, the WCD system may wait discreetly for the detected cardiac arrhythmia to self-terminate relatively quickly, without outputting such a sound until then.

Such arrhythmias that self-terminate quickly may occur from likely harmless events, possibly occurring multiple times in the daily life of the patient. For example, the patient may experience a brief episode of tachycardia, or become “winded”, from climbing stairs. In some of these embodiments, the WCD system may wait for such an arrhythmia event to terminate, and notify the patient only discreetly, or even not at all. The lack of sounding such a loud alarm responsive to such events reduces the overall number of times in which the patient experiences unwanted attention by others, embarrassment, loss of privacy and dignity, and so on.

These and other features and advantages of this description will become more readily apparent from the Detailed Description, which proceeds with reference to the associated drawings in which:

DETAILED DESCRIPTION

As has been mentioned, the present description is about wearable cardioverter defibrillator (“WCD”) systems, storage media that store programs, and methods. Embodiments are now described in more detail.

A wearable cardioverter defibrillator (“WCD”) system made according to embodiments has a number of components. These components can be provided separately as modules that can be interconnected, or can be combined with other components, etc.

FIG. 1depicts a patient82. Patient82may also be referred to as a person and/or wearer, since that patient wears components of the WCD system.

FIG. 1also depicts components of a WCD system made according to embodiments. One such component is a support structure170that is wearable by patient82. It will be understood that support structure170is shown only generically inFIG. 1, and in fact partly conceptually.FIG. 1is provided merely to illustrate concepts about support structure170, and is not to be construed as limiting how support structure170is implemented, or how it is worn.

Support structure170can be implemented in many different ways. For example, it can be implemented in a single component or a combination of multiple components. In embodiments, support structure170could include a vest, a half-vest, a garment, etc. In such embodiments such items can be worn similarly to parallel articles of clothing. In embodiments, support structure170could include a harness, one or more belts or straps, etc. In such embodiments, such items can be worn by around the torso, hips, over the shoulder, etc. In embodiments, support structure170can include a container or housing, which can even be waterproof. In such embodiments, the support structure can be worn by being attached to the patient by adhesive material, for example as shown in U.S. Pat. No. 8,024,037. Support structure170can even be implemented as described for the support structure of U.S. Pat. App. No. U.S. 2017/0056682A1, which is incorporated herein by reference. Of course, in such embodiments, a person skilled in the art will recognize that additional components of the WCD system can be in the housing of a support structure instead of attached externally to the support structure, for example as described in the document incorporated by reference. There can be other examples.

A WCD system according to embodiments is configured to defibrillate a patient who is wearing it, by delivering an electrical charge to the patient's body in the form of an electric shock delivered in one or more pulses.FIG. 1shows a sample external defibrillator100, and sample defibrillation electrodes104,108, which are coupled to external defibrillator100via electrode leads105. Defibrillator100and defibrillation electrodes104,108are coupled to support structure170. As such, many of the components of defibrillator100can be therefore coupled to support structure170. When defibrillation electrodes104,108make good electrical contact with the body of patient82, defibrillator100can administer, via electrodes104,108, a brief, strong electric pulse111through the body. Pulse111, also known as a defibrillation shock or therapy shock, is intended to go through and restart heart85, in an effort to save the life of patient82. Pulse111can further include one or more pacing pulses, and so on.

A prior art defibrillator typically decides whether to defibrillate or not based on an ECG signal of the patient. However, defibrillator100can defibrillate, or not defibrillate, also based on other inputs.

The WCD system may optionally include an outside monitoring device180. Device180is called an “outside” device because it is provided as a standalone device, for example not within the housing of defibrillator100. Device180can be configured to monitor at least one local parameter. A local parameter can be a parameter of patient82, or a parameter of the WCD system, or a parameter of the environment, as will be described later in this document.

Optionally, device180is physically coupled to support structure170. In addition, device180can be communicatively coupled with other components, which are coupled to support structure170. Such communication can be implemented by a communication module, as will be deemed applicable by a person skilled in the art in view of this disclosure.

FIG. 2is a diagram showing components of an external defibrillator200, made according to embodiments. These components can be, for example, included in external defibrillator100ofFIG. 1. The components shown inFIG. 2can be provided in a housing201, which is also known as casing201.

External defibrillator200is intended for a patient who would be wearing it, such as patient82ofFIG. 1. Defibrillator200may further include a user interface270for a user282. User282can be patient82, also known as wearer82. Or user282can be a local rescuer at the scene, such as a bystander who might offer assistance, or a trained person. Or, user282might be a remotely located trained caregiver in communication with the WCD system.

User interface270can be made in any number of ways. User interface270may include output devices, which can be visual, audible or tactile, for communicating to a user. For example, an output device can be a light, or a screen to display what is detected and measured, and provide visual feedback to rescuer282for their resuscitation attempts, and so on. Other output devices can be speakers271,272, etc. Such a speaker can be any device that can output a sound, whether speech or not. For example, speaker271can be configured to issue voice prompts, etc. Speaker272can be an electronic audible alarm such as a siren, a sonalert, etc. Sounds, lights, images, vibrations, and anything that can be perceived by user282can also be called human-perceptible indications. In diagrams that accompany the present description, a “human-perceptible indication” may be abbreviated as “HPI”. User interface270may also include input devices for receiving inputs from users. Such input devices may additionally include various controls, such as pushbuttons, keyboards, touchscreens, a microphone, and so on. An input device can be a cancel switch, which is sometimes called a “live-man” switch and a divert button. In some embodiments, actuating the cancel switch can prevent the impending delivery of a shock.

Defibrillator200may include an internal monitoring device281. Device281is called an “internal” device because it is incorporated within housing201. Monitoring device281can monitor patient parameters, patient physiological parameters, system parameters and/or environmental parameters, all of which can be called patient data. In other words, internal monitoring device281can be complementary or an alternative to outside monitoring device180ofFIG. 1. Allocating which of the system parameters are to be monitored by which monitoring device can be done according to design considerations.

Patient physiological parameters include, for example, those physiological parameters that can be of any help in detecting by the wearable defibrillation system whether the patient is in need of a shock, plus optionally their medical history and/or event history. Examples of such parameters include the patient's ECG, blood oxygen level, blood flow, blood pressure, blood perfusion, pulsatile change in light transmission or reflection properties of perfused tissue, heart sounds, heart wall motion, breathing sounds and pulse. Accordingly, the monitoring device could include a perfusion sensor, a pulse oximeter, a Doppler device for detecting blood flow, a cuff for detecting blood pressure, an optical sensor, illumination detectors and perhaps sources for detecting color change in tissue, a motion sensor, a device that can detect heart wall movement, a sound sensor, a device with a microphone, an SpO2 sensor, and so on. Pulse detection is taught at least in Physio-Control's U.S. Pat. No. 8,135,462, which is hereby incorporated by reference in its entirety. In addition, a person skilled in the art may implement other ways of performing pulse detection.

In some embodiments, the local parameter is a trend that can be detected in a monitored physiological parameter of patient82. A trend can be detected by comparing values of parameters at different times. Parameters whose detected trends can particularly help a cardiac rehabilitation program include: a) cardiac function (e.g. ejection fraction, stroke volume, cardiac output, etc.); b) heart rate variability at rest or during exercise; c) heart rate profile during exercise and measurement of activity vigor, such as from the profile of an accelerometer signal and informed from adaptive rate pacemaker technology; d) heart rate trending; e) perfusion, such as from SpO2 or CO2; f) respiratory function, respiratory rate, etc.; g) motion, level of activity; and so on. Once a trend is detected, it can be stored and/or reported via a communication link, along perhaps with a warning. From the report, a physician monitoring the progress of patient82will know about a condition that is either not improving or deteriorating.

Patient state parameters include recorded aspects of patient82, such as motion, posture, whether they have spoken recently plus maybe also what they said, and so on, plus optionally the history of these parameters. Or, one of these monitoring devices could include a location sensor such as a global positioning system (“GPS”) location sensor. Such a sensor can detect the location, plus a speed can be detected as a rate of change of location over time. Many motion detectors output a motion signal that is indicative of the motion of the detector, and thus of the patient's body. Patient state parameters can be very helpful in narrowing down the determination of whether SCA is indeed taking place.

A WCD system made according to embodiments may include a motion detector. In embodiments, a motion detector can be implemented within monitoring device180or monitoring device281. Such a motion detector can be configured to detect a motion event. In response, the motion detector may render or generate from the detected motion event a motion detection input that can be received by a subsequent device or functionality. A motion event can be defined as is convenient, for example a change in motion from a baseline motion or rest, etc. Such a motion detector can be made in many ways as is known in the art, for example by using an accelerometer.

System parameters of a WCD system can include system identification, battery status, system date and time, reports of self-testing, records of data entered, records of episodes and intervention, and so on.

Environmental parameters can include ambient temperature and pressure. A humidity sensor may provide information as to whether it is likely raining. Presumed patient location could also be considered an environmental parameter. The patient location could be presumed if monitoring device180or281includes a GPS location sensor as per the above.

Defibrillator200typically includes a defibrillation port210, such as a socket in housing201. Defibrillation port210includes electrical nodes214,218. Leads of defibrillation electrodes204,208, such as leads105ofFIG. 1, can be plugged into defibrillation port210, so as to make electrical contact with nodes214,218, respectively. It is also possible that defibrillation electrodes204,208are connected continuously to defibrillation port210, instead. Either way, defibrillation port210can be used for guiding, via electrodes, to the wearer the electrical charge that has been stored in energy storage module250. The electric charge will be the shock for defibrillation, pacing, and so on.

Defibrillator200may optionally also have an ECG port219in housing201, for plugging in sensing electrodes209, which are also known as ECG electrodes and ECG leads. It is also possible that sensing electrodes209can be connected continuously to ECG port219, instead. Sensing electrodes209can help sense an ECG signal, e.g. a 12-lead signal, or a signal from a different number of leads, especially if they make good electrical contact with the body of the patient. Sensing electrodes209can be attached to the inside of support structure170for making good electrical contact with the patient, similarly as defibrillation electrodes204,208.

Optionally a WCD system according to embodiments also includes a fluid that it can deploy automatically between the electrodes and the patient skin. The fluid can be conductive, such as by including an electrolyte, for making a better electrical contact between the electrode and the skin. Electrically speaking, when the fluid is deployed, the electrical impedance between the electrode and the skin is reduced. Mechanically speaking, the fluid may be in the form of a low-viscosity gel, so that it does not flow away, after it has been deployed. The fluid can be used for both defibrillation electrodes204,208, and sensing electrodes209.

The fluid may be initially stored in a fluid reservoir, not shown inFIG. 2, which can be coupled to the support structure. In addition, a WCD system according to embodiments further includes a fluid deploying mechanism274. Fluid deploying mechanism274can be configured to cause at least some of the fluid to be released from the reservoir, and be deployed near one or both of the patient locations, to which the electrodes are configured to be attached to the patient. In some embodiments, fluid deploying mechanism274is activated responsive to receiving activation signal AS from processor230, prior to the electrical discharge.

Defibrillator200also includes a measurement circuit220. Measurement circuit220receives physiological signals of the patient from ECG port219, if provided. Even if defibrillator200lacks ECG port219, measurement circuit220can obtain physiological signals through nodes214,218instead, when defibrillation electrodes204,208are attached to the patient. In these cases, the patient's ECG signal can be sensed as a voltage difference between electrodes204,208. Plus, impedance between electrodes204,208and/or the connections of ECG port219can be sensed. Sensing the impedance can be useful for detecting, among other things, whether these electrodes204,208and/or sensing electrodes209are not making good electrical contact with the patient's body. These patient physiological signals can be sensed, when available. Measurement circuit220can then render or generate information about them as physiological inputs, data, other signals, etc. More strictly speaking, the information rendered by measurement circuit220is output from it, but this information can be called an input because it is received by a subsequent device or functionality as an input.

Defibrillator200also includes a processor230. Processor230may be implemented in any number of ways. Such ways include, by way of example and not of limitation, digital and/or analog processors such as microprocessors and digital signal processors (“DSP”s); controllers such as microcontrollers; software running in a machine; programmable circuits such as field programmable gate arrays (“FPGA”s), field-programmable analog arrays (“FPAA”s), programmable logic devices (“PLD”s), application specific integrated circuits (“ASIC”s), any combination of one or more of these, and so on.

Processor230can be considered to have a number of modules. One such module can be a detection module232. Detection module232can include a ventricular fibrillation (“VF”) detector. The patient's sensed ECG from measurement circuit220, which can be available as physiological inputs, data, or other signals, may be used by the VF detector to determine whether the patient is experiencing VF. Detecting VF is useful, because VF results in SCA. Detection module232can also include a ventricular tachycardia (“VT”) detector, and so on.

Another such module in processor230can be an advice module234, which generates advice for what to do. The advice can be based on outputs of detection module232. There can be many types of advice according to embodiments. In some embodiments, the advice is a shock/no shock determination that processor230can make, for example via advice module234. The shock/no shock determination can be made by executing a stored Shock Advisory Algorithm. A Shock Advisory Algorithm can make a shock/no shock determination from one or more of ECG signals that are captured according to embodiments, and determining whether a shock criterion is met. The determination can be made from a rhythm analysis of the captured ECG signal or otherwise.

In some embodiments, when the decision is to shock, an electrical charge is delivered to the patient. Delivering the electrical charge is also known as discharging. Shocking can be for defibrillation, pacing, and so on.

Processor230can include additional modules, such as other module236, for other functions. In addition, if internal monitoring device281is indeed provided, it may be operated in part by processor230, etc.

Defibrillator200optionally further includes a memory238, which can work together with processor230. Memory238may be implemented in any number of ways. Such ways include, by way of example and not of limitation, volatile memories, nonvolatile memories (“NVM”), read-only memories (“ROM”), random access memories (“RAM”), magnetic disk storage media, optical storage media, smart cards, flash memory devices, any combination of these, and so on. Memory238is thus a non-transitory storage medium. Memory238, if provided, can include programs for processor230, which processor230may be able to read and execute. More particularly, the programs can include sets of instructions in the form of code, which processor230may be able to execute upon reading. Executing is performed by physical manipulations of physical quantities, and may result in functions, processes, actions and/or methods to be performed, and/or the processor to cause other devices or components or blocks to perform such functions, processes, actions and/or methods. The programs can be operational for the inherent needs of processor230, and can also include protocols and ways that decisions can be made by advice module234. In addition, memory238can store prompts for user282, if this user is a local rescuer. Moreover, memory238can store data. The data can include patient data, system data and environmental data, for example as learned by internal monitoring device281and outside monitoring device180. The data can be stored in memory238before it is transmitted out of defibrillator200, or stored there after it is received by defibrillator200.

Defibrillator200may also include a power source240. To enable portability of defibrillator200, power source240typically includes a battery. Such a battery is typically implemented as a battery pack, which can be rechargeable or not. Sometimes a combination is used of rechargeable and non-rechargeable battery packs. Other embodiments of power source240can include an AC power override, for where AC power will be available, an energy storage capacitor, and so on. In some embodiments, power source240is controlled by processor230.

Defibrillator200additionally includes an energy storage module250, which can thus be coupled to the support structure of the WCD system. Module250is where some electrical energy is stored in the form of an electrical charge, when preparing it for discharge to administer a shock. Module250can be charged from power source240(by receiving an electrical charge) to the right amount of energy, as controlled by processor230. In typical implementations, module250includes a capacitor252, which can be a single capacitor or a system of capacitors, and so on. As described above, capacitor252can store the energy in the form of an electrical charge, for delivering to the patient.

Defibrillator200moreover includes a discharge circuit255. When the decision is to shock, processor230can be configured to control discharge circuit255to discharge through the patient the electrical charge stored in energy storage module250. When so controlled, circuit255can permit the energy stored in module250to be discharged to nodes214,218, and from there also to defibrillation electrodes204,208, so as to cause a shock to be delivered to the patient while the support structure is worn by the patient. Circuit255can include one or more switches257. Switches257can be made in a number of ways, such as by an H-bridge, and so on. Circuit255can also be controlled via user interface270.

Defibrillator200can optionally include a communication module290, for establishing one or more wired or wireless communication links with other devices of other entities, such as a remote assistance center, Emergency Medical Services (“EMS”), and so on. Module290may also include an antenna, portions of a processor, and other sub-components as may be deemed necessary by a person skilled in the art. This way, data and commands can be communicated, such as patient data, event information, therapy attempted, CPR performance, system data, environmental data, and so on.

Defibrillator200can optionally include other components.

Returning toFIG. 1, in embodiments, one or more of the components of the shown WCD system have been customized for patient82. This customization may include a number of aspects. For instance, support structure170can be fitted to the body of patient82. For another instance, baseline physiological parameters of patient82can be measured, such as the heart rate of patient82while resting, while walking, motion detector outputs while walking, etc. Such baseline physiological parameters can be used to customize the WCD system, in order to make its diagnoses more accurate, since bodies behave differently. For example, such parameters can be stored in a memory of the WCD system, and so on.

A programming interface can be made according to embodiments, which receives such measured baseline physiological parameters. Such a programming interface may input automatically in the WCD system the baseline physiological parameters, along with other data.

FIG. 3Ais a rendering of diagram in a publication that describes characteristics of a WCD system in the prior art, with annotations added in this document. In particular,FIG. 3Ais labeled “FIG. 3” in that publication, which is: KLEIN Helmut U., GOLDENBERG Ilan & MOSS Arthur J., Risk stratification for implantable cardioverter defibrillator therapy: the role of the wearable cardioverter-defibrillator, European Heart Journal, 2013, pp. 1-14, doi:10.1093/eurheartj/eht167.

InFIG. 3A, the diagram of the prior art is designated in the rectangle301. It purports to describe the detection, treatment and alarm system of a prior art WCD system. Attention is drawn to designated sections311,321of this diagram.

FIG. 3Bshows a magnification of designated section311of the prior art diagram ofFIG. 3A, with further annotations along an added time axis312. Section311is characterized as detection time, shock delivery, and electrocardiogram recording after shock delivery. In the added time axis312, certain events of section311have intercepts TA, TB, TD, TE, TF, TG, TH as shown, for easier reference.

In section311, the time duration between TA and TD seems to be 30 sec along time axis312. Section311seems to further show ECG data360. This ECG data360seems to include QRS complexes371,372,373,391,392. Between times TB and TE there is an ECG portion380. ECG portion380seems to be a cardiac arrhythmia, since it seems to lack QRS complexes, and to further be the cause for the alarms at TD and shock delivery at time TF. In that case, the onset of the cardiac arrhythmia of portion380takes place at time TB. By time TD, detection seems to have happened. Judging from the fact that the duration from TA to TD is 30 sec, the duration from TB to TD seems to be no more than 5 sec, if the time axis of that time diagram is to scale.

FIG. 3Cshows a magnification of designated section321of the prior art diagram ofFIG. 3A, with further annotations along an added time axis322. Section321is characterized as the time sequence of alarms, etc. In particular, timeline331is characterized as ECG record, timeline332is characterized as Validation period, timeline333is characterized as Alarms active, timeline334is characterized as Vibration alarm, timeline335is characterized as Siren, timeline336is characterized as Loud siren, timeline337is characterized as Bystander warning, timeline338is characterized as Gel release, and timeline339is characterized as Treatment shock.

InFIG. 3C, in the added time axis322, certain events of section321have intercepts TA, TC, TD, TF as shown, for easier reference. Some of these are the same time intercepts as those in time axis312ofFIG. 3B. In addition, time intercept TB ofFIG. 3Bcould be the same as time intercept TC ofFIG. 3C.

As mentioned above, embodiments of the invention include systems, processors and methods. The devices and/or systems mentioned in this document perform functions, processes and/or methods. These functions, processes and/or methods may be implemented by one or more devices that include logic circuitry. Such a device can be alternately called a computer, and so on. It may be a standalone device or computer, such as a general purpose computer, or part of a device that has one or more additional functions. The logic circuitry may include a processor and non-transitory computer-readable storage media, such as memories, of the type described elsewhere in this document. Often, for the sake of convenience only, it is preferred to implement and describe a program as various interconnected distinct software modules or features. These, along with data are individually and also collectively known as software. In some instances, software is combined with hardware, in a mix called firmware.

Moreover, methods and algorithms are described below. These methods and algorithms are not necessarily inherently associated with any particular logic device or other apparatus. Rather, they are advantageously implemented by programs for use by a computing machine, such as a general-purpose computer, a special purpose computer, a microprocessor, a processor such as described elsewhere in this document, and so on.

This detailed description includes flowcharts, display images, algorithms, and symbolic representations of program operations within at least one computer readable medium. An economy is achieved in that a single set of flowcharts is used to describe both programs, such that can be executed by a processor, and also methods. So, while flowcharts described methods in terms of boxes, they also concurrently describe programs.

Methods are Now Described.

In some embodiments, a WCD system may output an opening human-perceptible indication, after detecting a shockable cardiac arrhythmia but before completing its analysis of the cardiac arrhythmia, for instance before validating the cardiac arrhythmia. Examples are now described.

FIG. 4shows a flowchart400for describing methods according to embodiments. In addition,FIG. 5is a time diagram of a sample series of events that may result from methods of the flowchart ofFIG. 4. Of course, a different series of events may result from the methods of the flowchart ofFIG. 4. The events ofFIG. 5are shown along a time axis512, with intercepts that are not to scale. This portion of this description proceeds by referring to both diagrams.

According to an operation410ofFIG. 4, a patient physiological signal may be monitored. The physiological signal can be the patient's electrocardiogram (“ECG”), impedance, blood pressure, blood oxygen saturation, and so on. As mentioned previously, measurement circuit220, or equivalently another transducer, may render a physiological input from the monitored patient physiological signal. InFIG. 5, a timeline510indicates that the physiological input starts being received at a time T1, by switching from a low value to a high value.

According to another operation415ofFIG. 4, it is inquired whether a cardiac arrhythmia is detected from the physiological input. It will be understood that this means a cardiac arrhythmia of interest, namely a shockable cardiac arrhythmia such as VF or VT. A difference between VF and VT is that the patient becomes unconscious very soon after VF starts, while the patient may remain conscious throughout a VT episode, whether prolonged or not. As will be seen, embodiments may provide a longer confirmation period for VT than VF, which works well with the fact that VT sometimes self-terminates, while VF almost never does.

While at operation415no cardiac arrhythmia is being detected, execution returns to operation410. This cardiac arrhythmia detection is shown inFIG. 5along a timeline515. There is no detection while timeline515has a low value. Detection may happen at time T2, at which time timeline515changes to a high value. At that time, detection may have been performed using inputs received earlier.

Returning toFIG. 4, if detection happens at operation415then, according to another operation420, it can be determined whether or not the cardiac arrhythmia is validated, for example according to a validation criterion, meaning depending on whether or not the validation criterion is met. For example, the validation criterion may include that the detected cardiac arrhythmia needs to be maintained for a threshold validation time. The determination of whether or not the detected cardiac arrhythmia meets the validation criterion can be made from one of the physiological inputs. Operation420may need some time to be performed.

In addition, according to another operation472, an opening human-perceptible indication (“HPI”) may be caused to be output responsive to detecting the cardiac arrhythmia. This opening HPI may be caused to be output prior to completing the determination of operation420. Accordingly, the execution of operations420,472may overlap in time at least in part. In the example ofFIG. 5, timeline520shows validation being performed between times T2and T5. Moreover, timeline572shows an example of when the opening HPI is performed, and in particular lasting between times T3and T4. This opening HPI may be caused to be output at a time T3, which is prior to completing the determination of operation420at time T5.

It will be appreciated that, if the patient is having a VF episode, he or she might be unconscious and never perceive this opening HPI. On the other hand, if the patient's arrhythmia is a VT episode, he or she may well be conscious and perceive their own arrhythmia.

In embodiments where this opening HPI is caused to be output prior to completing the determination of operation420, the system might not know yet whether it will shock the patient or not. Indeed, if the cardiac arrhythmia turns out to be a mild VT, and the patient is still conscious, perhaps a shock will not be called for, eventually. A longer threshold validation time may be called for, during which the VT may self-terminate. As will be seen later in this document, in some embodiments where the VT is detected to self-terminate, no shock is administered to the conscious patient. Of course, if the VT becomes fast VT and degenerates into VF, a shock will be needed.

Since this opening HPI is caused to be output prior to completing the determination of operation420, in some embodiments this opening HPI may fulfill the function of giving comfort and confidence to the patient that their WCD system is working, while they do not have to do anything, such as immediately stopping what they are doing to frantically search for the cancel switch so as to avoid a shock while conscious. Nor will they be embarrassed in front of others, if the opening HPI is discreet, and the cardiac arrhythmia eventually self-terminates. The opening HPI might give such comfort and confidence to a person who is having a sustained episode of low-rate VT that causes them to feel uncomfortable (“crummy”), even though they don't need to be shocked. Such an episode may self-terminate. In addition, the opening HPI might give such comfort and confidence to someone who learns news that excites them, such as by watching a sports event. Such a person may experience a high-rate supra-ventricular (SVT) rhythm that can make them feel crummy as well, even though they don't need to be shocked, either.

In order to give the patient this comfort and confidence, the opening HPI may communicate to the patient that at least some analysis will be performed on the cardiac arrhythmia, for example to determine whether or not it is validated. Such communicating may be explicit, for example by the opening HPI including a voice message to the effect of “HAVE DETECTED ARRHYTHMIA OF YOUR HEART, AND NOW VALIDATING IT”. Alternately, an opening HPI can be more discreet, so that only the patient will perceive it. Such a more discreet opening HPI can be a tactile signal like a vibration, whose meaning the patient will have been trained to understand. For example, the opening HPI can be a group of three consecutive vibrations, perhaps each having the same duration. Of course, the vibrations will have to be designed to be intense enough and prolonged enough to be perceptible by a patient above and beyond their possible VT, given that a VT is itself a vibration within their body.

In some instances, the determination of operation420may take longer, for example longer than 30 sec. In such cases, the opening HPI may be extended, for the patient's confidence in the WCD to be sustained through the validation process. In some embodiments, the opening HPI may be caused to be output for as long as operation420is being performed, but that is not an example ofFIG. 5, where the time T4ends before time T5. To extend the example above, the group of three vibrations may be repeated every 7 to 10 sec.

Subsequent operations may depend on the determination of whether or not the cardiac arrhythmia is so validated. According to another operation425ofFIG. 4, if it is determined that the cardiac arrhythmia is not so validated, execution may return to operation410. Where it is written in this document that it is determined that the cardiac arrhythmia is or is not so validated, it means to be or not be validated according to the previously mentioned validation criterion, the determination of such validation, etc.

When according to operation425it is determined that the cardiac arrhythmia is not so validated, execution may return to operation410by further optionally executing another operation477. According to operation477, a closing HPI is caused to be output, in a manner and for an effect that are described later in this document for an operation677ofFIG. 6. In such a case, the discharge circuit can be controlled to not deliver a shock for some time, e.g. at least 25 min from when the opening HPI was caused to be output at operation472ofFIG. 4, because the patient may not need a shock for that time, or for that event.

InFIG. 5, box525can be another example of box425. If it is determined that the cardiac arrhythmia is not so validated, timeline541indicates that no warning HPI is caused to be output and timeline597indicates that no shock is delivered. In addition, timeline578indicates that a closing HPI event577may be caused to be output, such as by operation477.

Returning toFIG. 4, if at operation425it is determined that the cardiac arrhythmia is so validated then, according to another operation440, a warning HPI can be caused to be output. The warning HPI can be configured to communicate that a shock will be delivered imminently.

The warning HPI can be distinct from the opening HPI. In particular, the indications can be different in content, in the way they are delivered, and/or in the meaning that they are designed to convey to the patient. For example, in some embodiments the opening HPI communicates to the patient that their WCD system has not made a determination yet, and it does not require the patient to do anything to avoid a shock. On the other hand, in many embodiments the warning HPI of operation440informs that a shock is imminent unless the patient does something, like enter a cancel input in the user interface.

According to an optional next operation494, if a cancel input is received, execution may return to operation410. In particular, the user interface can be configured to receive a cancel input. Even if the cardiac arrhythmia is so validated, the discharge circuit can be controlled to instead not deliver a shock responsive to the cardiac arrhythmia, if a cancel input is received by the user interface within a time window after the warning HPI of operation440is caused to be output.

Else, if at operation494a cancel input is not received then, according to another operation499, the discharge circuit is instead controlled to deliver a shock, for example within 3 min from when the warning HPI was caused to be output for that event, and preferably before 3 min passes.

InFIG. 5, from box525, if it is determined that the cardiac arrhythmia is so validated, a timeline542indicates that a warning HPI event543can take place, for example according to operation440. In addition, timeline598indicates that a shock delivery event599may take place, while timeline579indicates that no closing HPI event takes place.

These embodiments that include an opening HPI can be combined with other embodiments. For example, from this document alone, these other embodiments include ones with a closing HPI, embodiments where there is confirmation of the cardiac arrhythmia in addition to validation, embodiments with shocking if the patient has VF but not necessarily if VT, a different delay or validation time for VT than for VF, a different HPI for VT than for VF, etc.

In some embodiments, a WCD system may output a closing human-perceptible indication (“HPI”), after detecting a shockable cardiac arrhythmia, and after further determining that it will not shock. The closing HPI may be associated with closing an event, such as when an event is closed in software, where a record is kept. Examples are now described.

FIG. 6shows a flowchart600for describing methods according to embodiments. Flowchart600has many elements that are similar to flowchart400ofFIG. 4. In addition, the sample series of events ofFIG. 5may also result from methods of the flowchart ofFIG. 6.

InFIG. 6, operations610,615,620,672,625,640and694can be performed as described respectively for operations410,415,420,472,425,440, and494ofFIG. 4. In other words, a shockable cardiac arrhythmia is detected, etc. Of those operations, at least operations672and694are optional.

If, at operation625it is determined that the cardiac arrhythmia is so validated then, according to an operation699, the discharge circuit can be controlled to instead deliver a shock within some time from when it was determined that the cardiac arrhythmia is so validated. The shock can be delivered, for example within 2.5 min or less, for this event.

If, at operation625it is determined that the cardiac arrhythmia is not so validated, execution may return to operation610without shocking for this event. In addition, according to another operation677, a closing HPI is caused to be output. The closing HPI can be configured to communicate to the patient that it was decided not to shock responsive to the cardiac arrhythmia, so the patient can relax and return to his or her other business. This may be communicated in a number of ways. In some embodiments, the closing HPI includes a voice message, which can say something like: “HAPPY THAT YOUR RHYTHM IS RESTORED, WILL NOT SHOCK THIS TIME”. In alternate, and more discreet, embodiments the closing HPI includes one or more vibrations. For example, a group of consecutive vibrations may be used, which have progressively diminishing intensities. If, at operation625it is determined that the cardiac arrhythmia is not so validated, the discharge circuit can be further controlled to not deliver a shock for some time from when it was determined that the cardiac arrhythmia is not so validated, for example for at least 25 min. Of course, this time can become shorter if the patient has another event soon thereafter, and so on.

These embodiments that include a closing HPI can be combined with other embodiments. For example, from this document alone, these other embodiments include ones with an opening HPI, embodiments where there is confirmation of the cardiac arrhythmia in addition to validation, embodiments with shocking if the patient has VF but not necessarily if VT, a different delay or validation time for VT than for VF, a different HPI for VT than for VF, etc.

In some embodiments, a WCD system may first determine whether or not the cardiac arrhythmia is validated, for example according to a validation criterion. If so, the WCD system may further determine whether or not the cardiac arrhythmia is confirmed according to a confirmation criterion, and then shock or not shock accordingly. Examples are now described.

FIG. 7shows a flowchart700for describing methods according to embodiments. In addition,FIG. 8is a time diagram of a sample series of events that may result from methods of the flowchart ofFIG. 7. Of course, a different series of events may result from the methods of the flowchart ofFIG. 7. The events ofFIG. 8are shown along a time axis812, with intercepts that are not to scale. This portion of this description proceeds by referring to both diagrams.

InFIG. 7, operations710,715,720,725,740,794and777can be performed as previously described for respectively operations410,415,420,425,440,494and677. In other words, a shockable cardiac arrhythmia is detected, etc. Of those operations, at least operations740,794and777are optional. InFIG. 8, timelines810,815,820can be as described for timelines510,515and520. In addition, an opening HPI may be caused to be output as per the above, but such is not shown so as not to obscure the drawings.

If, at operation725it is determined that the detected cardiac arrhythmia is so validated then, according to another operation770, a certain HPI can be caused to start being output. The certain HPI can accomplish a number of functions. One such function may be to inform the patient, who may be only tachycardic and thus conscious, that more analysis of their rhythm will be performed in the form of a confirmation. Again, this may give the patient the confidence that he or she will not be shocked unnecessarily, while they need not do anything to prevent a shock. After starting being output, the certain HPI of operation770can continue, to sustain the patient's confidence. For example, inFIG. 8, timeline870shows the certain HPI, which starts being output at time T6, and lasts until time T8.

Returning toFIG. 7, after operation770, according to another operation750it can be further determined whether or not the cardiac arrhythmia is confirmed. InFIG. 8, the confirmation of operation750is shown by a timeline850as taking place between times T7and T9. It will be appreciated that time T7in this example is after time T6, which is when the certain HPI started being output.

The determination of operation750can be performed according to a confirmation criterion, meaning depending on whether or not the confirmation criterion is met. The confirmation criterion can be different from or the same as the validation criterion. In some embodiments, the validation criterion can include that the cardiac arrhythmia is maintained for a validation time, the confirmation criterion can include that the cardiac arrhythmia is maintained for a confirmation time, and the confirmation time can be the same or different from the validation time. In some embodiments, the confirmation time is longer than the validation time, which is why the certain HPI may help the patient with their comfort that their system is working.

Subsequent operations may depend on the determination of whether the cardiac arrhythmia is so confirmed or not. Where it is written in this document that it is determined that the cardiac arrhythmia is or is not so confirmed, it means to be or not be confirmed according to the previously mentioned confirmation criterion, the determination of such confirmation, etc.

According to another operation755, if it is determined that the cardiac arrhythmia is not so confirmed, execution may return to operation710, with optionally also executing operation777as mentioned above for operation677. In such a case, there may be no shocking for this event in fact the discharge circuit can be controlled to not deliver a shock for some time, e.g. at least 22 min from when the cardiac arrhythmia is not so confirmed, because the patient may not need a shock for that time. Of course, this time can become shorter if the patient has another event soon thereafter, and so on.

If, at operation755it is determined that the cardiac arrhythmia is so confirmed then shocking may be needed for this event. Thus, according to an operation799, the discharge circuit can be controlled to deliver a shock within some time from when it was determined that the cardiac arrhythmia is so confirmed, for example within 4.8 min or preferably less.

Similarly, referring toFIG. 8, from box855, if it can be determined whether or not the cardiac arrhythmia is so confirmed. If not, then timelines841and897can be as timelines541and597, respectively indicating no warning HPI and no shock. Else, if the cardiac arrhythmia is so confirmed, then timeline842indicates a warning HPI event843, and timeline898indicates a shock delivery event899.

These embodiments that include confirmation in addition to validation can be combined with other embodiments. For example, from this document alone, these other embodiments include ones with shocking if the patient has VF but not necessarily if VT, a different delay or validation time for VT than for VF, a different HPI for VT than for VF, etc.

In some embodiments, a WCD system may detect whether a cardiac arrhythmia is of a first type or of a second type. If the cardiac arrhythmia is of the first type, the WCD system may shock the patient anyway. If the cardiac arrhythmia is of the second type, however, the WCD system may determine whether or not the cardiac arrhythmia is confirmed, for example according to a confirmation criterion, and then shock or not shock accordingly. Examples are now described.

FIG. 9shows a flowchart900for describing methods according to embodiments. InFIG. 9, operations910and915can be performed as described above for operations410and415respectively. In other words, a shockable cardiac arrhythmia is detected, etc. In addition, an opening HPI can optionally be caused to be output, for example prior to completing the determination of the type at operation930that is described later. Moreover, it may be optionally determined whether or not the cardiac arrhythmia is validated according to a validation criterion. In such embodiments, the opening HPI can be caused to be output prior to completing the determination of whether the cardiac arrhythmia is so validated. Subsequent actions, such as determining the type, validating, etc. may be performed responsive to determining that the cardiac arrhythmia is so validated.

If at operation915a cardiac arrhythmia is detected then, according to another operation930, it may be determined whether a type of the cardiac arrhythmia is at least one of a first type (“CA1”) and a second type (“CA2”). There can be two, three, or more possible such types. Embodiments may act differently, depending on the type determined at operation930.

In some embodiments, the first type (“CA1”) of detected cardiac arrhythmias includes Ventricular Fibrillation. In some embodiments, CA1includes Ventricular Tachycardia, where a heart rate of the patient has a value larger than a first heart rate threshold. An example is now described.

FIG. 10shows a diagram1030, where detected cardiac arrhythmias may be plotted according to their heart rate. In diagram1030a HEART RATE axis has a first heart rate threshold HRT1. Suggested values for HRT1are discussed below. The type of cardiac arrhythmias whose heart rate has a value larger than HRT1can be determined to be CA1. The remaining cardiac arrhythmias can be determined to be either all of the same type (e.g. CA2), or further subdivided according to additional types, etc. It will be appreciated, then, that fast VT may be thus classified as type CA1, while slower VT otherwise.

In some embodiments, the second type (“CA2”) of detected cardiac arrhythmias includes Ventricular Tachycardia, where a heart rate of the patient has a value less than a second heart rate threshold. An example is now described.

FIG. 11shows a diagram1130, where detected cardiac arrhythmias may be plotted according to their heart rate. In diagram1130a HEART RATE axis has a second heart rate threshold HRT2. Suggested values for HRT1are discussed below. The type of cardiac arrhythmias whose heart rate has a value less than HRT2can be determined to be CA2. The remaining cardiac arrhythmias can be determined to be either all of the same type (e.g. CA1), or further subdivided according to additional types, etc. It will be appreciated, then, that slower VT may be thus classified as type CA2.

In some embodiments, if a value of the heart rate of the patient is within a range, the type is determined to be CA1or CA2depending both on the value of the heart rate and on a value of a width of detected QRS complexes of the patient. An example is now described.

FIG. 12shows a diagram1230, where detected cardiac arrhythmias may be plotted according to both their heart rate and the width of QRS complexes, based on orthogonal axes. The horizontal axis is for the heart rate. The vertical axis is for the QRS width, which can be measured by the algorithm at the base of the QRS complex. It will be noted that the vertical axis starts at a minimum threshold value WTHR. Above that value, QRS complexes start deteriorating. Below that value, it is possible that no shock is advised. A good value for WTHR can be about 80 msec.

In diagram1230a broken line1231divides the space in two sectors or zones, one for CA1and one for CA2. At least the type of cardiac arrhythmias whose heart rate has a value larger than HRT3can be determined to be CA1, and at least the type of cardiac arrhythmias whose heart rate has a value less than HRT4can be determined to be CA2. In addition, if the value of the heart rate is within the range of HRT4and HRT3, then the type can be determined depending both on the value of the heart rate on the horizontal axis and on a value of a width of detected QRS complexes on the vertical axis. The determination takes place from line segment1232of broken line1231.

A good value for HRT4is 170 bpm (beats per minute). A good value for HRT3is 200 bpm. A good value for W3is 120 msec, and for W4is 150 msec. Once values for these parameters are determined, then an equation can be constructed for line segment1232using analytic geometry, for a processor to use.

In the example ofFIG. 12, broken line1231has only linear segments, but that is only an example. Linear segments are preferred, because the computation for the determination of operation930is easier, as seen for line segment1232.

Where performing such computations based on the QRS width would be too taxing on resources, and where only two types need be determined, thenFIGS. 10 and 11may be used in a combined form. In such a case, HRT1can be set equal to HRT2, and both can have a value between the proposed values of HRT3and HRT4, such as 200 bpm. In other words, the heart rhythms can be separated according to a certain heart rate threshold: CA1may include a rhythm where a heart rate of the patient has a value less than the certain heart rate threshold, while CA2may include a rhythm where the heart rate has a value larger than the certain heart rate threshold. The certain heart rate threshold can be, for example 200 bpm; a rate higher than that can be designated as the VF zone, while a rate of 170-200 bpm can be designated as the VT zone.

In some embodiments, there are two types of cardiac arrhythmias: shockable VF/shockable VT. In addition to the heart rate and the QRS width, one may further incorporate another attribute called QRS organization. QRS organization might be assessed by cross-correlating detected QRS complexes. Rhythms in which the QRS complexes show a high correlation would be said to be relatively “organized,” while rhythms with a low correlation would be “disorganized.”

Accordingly, there may be no shock while the heart rate is <150 bpm and the QRS width <120 msec. At least monomorphic VT may be identified as a heart rate >150 bpm, QRS width >120 msec, and high QRS organization. VF may be identified as a heart rate is >200 bpm, QRS width >120 msec, and low QRS organization.

In some embodiments where the physiological signal is an ECG waveform, the distinction between CA1and CA2is based on an amplitude of an ECG waveform. A type of a cardiac arrhythmia can be CA1if its ECG waveform has an amplitude smaller than a threshold amplitude, and CA2if its ECG waveform has an amplitude larger than the threshold amplitude. The threshold amplitude can be a suitable value, for example 200 μV.

Returning toFIG. 9, according to another operation931, it is inquired which was the type of the detected cardiac arrhythmia determined at operation930. In the examples of this document, cardiac arrhythmias whose type is CA1are deemed more severe than otherwise, e.g. those whose type is CA2. Operation931anticipates that there could be two or even more types. For example, another type can be Atrial Fibrillation (“AF”).

In some embodiments, if at operation931it is determined that the type is CA1then, according to an operation999, the discharge circuit can be controlled to deliver a shock within sometime of determining the type, for example within 2.9 min and preferably less than that.

In some embodiments, if at operation931it is determined that the type is CA2then, according to another operation951, it can be further determined whether or not the cardiac arrhythmia is confirmed. This confirmation can be performed in a number of ways, as will be seen later in this document.

According to one more operation956, if the cardiac arrhythmia is so confirmed at operation951, then the discharge circuit can be controlled to deliver a shock according to operation999. Operation999may be thus performed within some time from when the cardiac arrhythmia is so confirmed at operation951, for example within 4.8 min. But if the cardiac arrhythmia is not so confirmed at operation951, then execution may return to operation910, and the discharge circuit can be controlled to not deliver a shock for some time. This time can be, for example at least 24 min from when the cardiac arrhythmia is not so confirmed at operation951. In addition, a closing HPI may be caused to be output responsive to the cardiac arrhythmia not being so confirmed, in conjunction with returning to operation910.

Operation951may be performed in a number of ways. It should be kept in mind that, in many embodiments, the detected cardiac arrhythmia at this time is known to be of the second type, which will hopefully self-terminate without needing to administer a shock. Examples are now described.

In some embodiments, it is determined whether or not the cardiac arrhythmia is confirmed according to a confirmation criterion. In some embodiments, the confirmation criterion includes that the cardiac arrhythmia is maintained for a confirmation time. In some embodiments, the confirmation criterion includes that a heart rate of the patient increases during a confirmation time. Additional embodiments are now described.

FIG. 13shows a flowchart1351for describing methods according to embodiments. Some of these methods may be applied to flowchart900, or others where a detected cardiac arrhythmia is being confirmed.

According to an operation1353, a confirmation timer may be started. According to another operation1310, a patient physiological signal may be monitored. At this point, if flowchart1351is applied to flowchart900, the patient physiological signal may help detect a cardiac arrhythmia of the second type (“CA2”).

According to another operation1314, it is inquired what cardiac rhythm is being detected. If the rhythm is a normal sinus rhythm (NSR), it may be that the heart rhythm has been restored by itself. Then, according to a state1356, the cardiac arrhythmia is not confirmed. If flowchart1351is being applied to flowchart900, execution then returns to operation910.

If at operation1314ofFIG. 13the cardiac arrhythmia is of the first type (“CA1”), such as VF or fast VT, execution may proceed to operation1399. The latter may be performed as operation999in flowchart900.

If at operation1314ofFIG. 13the cardiac arrhythmia is still of the second type (“CA2”), it may be that the patient has been experiencing VT. The above described option of checking as to whether the heart rate has been increasing persistently may be checked at this time.

At this stage, the patient may have become very uncomfortable with their cardiac rhythm, in fact so uncomfortable that the patient may prefer to be shocked over waiting for the arrhythmia to self-terminate. In some embodiments of a WCD system, the user interface is further configured to receive a shock input by the patient, such as by the patient pushing a button titled: “SHOCK ME NOW”. According to another operation1357, if such a shock input is received, execution may proceed to operation1399. In other words, in such embodiments, if the type has been determined to be CA2, the discharge circuit can be controlled to deliver a shock responsive to the received shock input. Operation1399can be performed within sometime after receiving the shock input, for example within 1.6 min of receiving the shock input.

If at operation1357no shock input has been received, then according to another operation1358it is inquired whether the confirmation timer that started at operation1353has timed out. If not, execution may return to operation1310. If yes then, according to a state1359, the cardiac arrhythmia is confirmed, and execution may proceed to operation1399.

These embodiments that shock a patient with VF but not necessarily with VT can be combined with other embodiments. For example, from this document alone, these other embodiments include ones with a different delay or validation time for VT than for VF, a different HPI for VT than for VF, etc.

In some embodiments, a WCD system may detect whether a cardiac arrhythmia is of a first type or of a second type. The WCD system may validate the detected cardiac arrhythmia, and output an HPI with a different delay, depending on the type. Examples are now described.

FIG. 14shows a flowchart1400for describing methods according to embodiments. In addition,FIG. 15is a time diagram of a sample series of events that may result from methods of the flowchart ofFIG. 14. Of course, a different series of events may result from the methods of the flowchart ofFIG. 14. The events ofFIG. 15are shown along a time axis1512, with intercepts that are not to scale. This portion of this description proceeds by referring to both diagrams.

InFIG. 14, operations1410,1415,1430and1431can be performed as described above for respective operations410,415,930and931. In other words, a shockable cardiac arrhythmia is detected, its type is determined, etc.

In parallel referring toFIG. 15, timelines1510and1515can be as described for timelines510and515. Moreover, timeline1530shows a type determination event1531of performing operation1430, which starts at time T11and ends at time T12.

In addition, although not shown in flowchart1400or inFIG. 15, in some embodiments an opening HPI is caused to be output responsive to detecting the cardiac arrhythmia, prior to completing the determination of the type. Moreover, the cardiac arrhythmia may be validated according to a validation criterion, and the opening HPI can be caused to be output prior to completing the determination of whether the cardiac arrhythmia is so validated. In some embodiments, type determination event1531is performed quickly and easily during such a validation, and thus it does not delay other actions.

If at operation1431it is determined that the type is CA1then, according to another operation1432, a first warning HPI is caused to be output. Operation1432may be performed after a first delay period elapses, since the type is determined at operation1430.

If at operation1431it is determined that the type is CA2then, according to another operation1436, a second warning HPI is caused to be output. The first warning HPI can be the same or different than the second warning HPI. It is preferred that they are the same, for the patient to not have to be trained to many different commands.

Operation1436may be performed after a second delay period elapses, since the type is determined at operation1430. The second delay period may have a duration at least 20% different from a duration of the first delay period. For example, the first delay period could be up to 10 sec, or even 20 sec. On the other hand, the second delay period can have a duration of 5-60 sec, and even longer, both for better analysis and also in order to give a VT the opportunity to self-terminate. In embodiments, these delay periods are programmable.

After operation1432or1436, according to an operation1499, the discharge circuit can be controlled to deliver a shock responsive to the cardiac arrhythmia. In some embodiments, this shock is canceled if, according to an operation1494, a cancel input is received within a time window. In other words, the discharge circuit can be controlled to instead not deliver a shock responsive to the cardiac arrhythmia and bypass operation1499, if a cancel input is received by the user interface within a time window after the first warning HPI or the second warning HPI is caused to be output.

InFIG. 15, box1531replicates the decision of box1431. In some embodiments, if the type is CA1, it may be determined during the first delay period whether the cardiac arrhythmia is confirmed according to a CA1confirmation criterion. The CA1confirmation criterion could be that the cardiac arrhythmia is maintained for a CA1confirmation time. Timeline1551shows the confirmation, where the CA1confirmation time lasts between T12and T14. The CA1confirmation time may be, for example 10 sec if CA1includes VF. Timeline1532then shows the first warning HPI event1537that starts at a later time T15.

In such embodiments, if the type is CA2, it may be determined during the second delay period whether the cardiac arrhythmia is confirmed according to a CA2confirmation criterion. The CA2confirmation criterion could be that the cardiac arrhythmia is maintained for a CA2confirmation time. Timeline1556shows this confirmation, where the CA2confirmation time lasts between T12and T16. Timeline1536then shows the second warning HPI event1533that starts at a later time T17. In this example, the CA2confirmation time has a duration at least 20% different from a duration of the CA1confirmation time. The CA2confirmation time may be, for example 45 sec if CA2includes VT. The differences in the confirmation times may account for the differences in the respective delay periods.

FIG. 15does not show the shock event that may follow the warning HPIs. This was done only not to clutterFIG. 15.

These embodiments that have a different delay or validation time for VT than for VF can be combined with other embodiments. For example, from this document alone, these other embodiments include ones with a different HPI for VT than for VF, etc.

In some embodiments, a WCD system may detect whether a cardiac arrhythmia is of a first type or of a second type. The WCD system may output different HPIs for the first type than the second type. Examples are now described.

FIG. 16shows a flowchart1600for describing methods according to embodiments. InFIG. 16, operations1610,1615,1630,1631,1694and1699can be performed as described above for respective operations1410,1415,1430,1431,1494and1499. In other words, a shockable cardiac arrhythmia is detected, its type is determined, etc.

In addition, although not shown in flowchart1600, in some embodiments an opening HPI is caused to be output responsive to detecting the cardiac arrhythmia, prior to completing the determination of the type. Moreover, the cardiac arrhythmia may be validated according to a validation criterion, and the opening HPI can be caused to be output prior to completing the determination of whether the cardiac arrhythmia is so validated.

If at operation1631it is determined that the type is CA1then, according to another operation1682, a first HPI is caused to be output. Else, if the type is CA2, according to another operation1686a second HPI is caused to be output.

The first HPI can be different from the second HPI for a number of reasons. For instance, the first HPI can be a warning HPI as described above, in which case entering a cancel input will avert a shock. On the other hand, the second HPI can be an HPI where the patient is informed that their rhythm is still being analyzed, whether that means being validated or confirmed.

The first HPI can be different from the second HPI in a number of ways. Examples are now described.

In some embodiments, the user interface includes at least a first and a second output device. The HPIs can come from different devices, in other words the first HPI can be output by the first output device, while the second HPI can be output by the second output device.

In some embodiments, the first and the second HPI can be from the same device. Examples are now described.

In some embodiments, the user interface includes a screen, but the displayed images are different. In other words, the first HPI can be a first image displayed by the screen, while the second HPI can be a second image displayed by the screen, which is different than the first image.

In some embodiments, the user interface includes a speaker that can play one or more audible sounds, but the sound messages are different. In other words, the first HPI can be a first sound message output by the speaker, while the second HPI can be a second sound message output by the speaker, which is different from the first sound message.

In some embodiments, the user interface includes an output device that can cause an HPI to be output at different intensity levels, be that louder for sound, brighter for light, more intense for vibration, and so on. The first HPI can be output by the output device at a first intensity level, while the second HPI can be output by the output device at a second intensity level, which is at least 20% different than the first intensity level. The intensity level may be measured by energy to actuate the device, perceived intensity by the user, etc.

In some embodiments, a WCD system may detect a shockable cardiac arrhythmia of the patient. The WCD system may try to validate or confirm the arrhythmia. It may fail to validate it in instances where, for example, the arrhythmia self-terminates relatively quickly. In such embodiments the WCD system, which has one or more output devices, might not output any loud sound before validation is completed, so as not to embarrass the patient to bystanders nearby. In addition, the patient may be spared of having to press the buttons to prove they are alive, and so on. In some of these embodiments, the WCD system might even not output any sound at all before validation is completed.

In some embodiments, the WCD system may try to validate or confirm the arrhythmia for a longer time than in the prior art, so as to give it a further chance to self-terminate. In such embodiments, the WCD system may transmit or even record data of the self-terminating arrhythmia for later analysis. In some of these embodiments, the WCD system may notify the patient only discreetly, or even not at all. Examples are now described.

FIG. 17shows a flowchart1700for describing methods according to embodiments where a detected cardiac arrhythmia is given a further chance to self-terminate, sometimes by being validated for a longer time. In addition,FIG. 18is a time diagram of a sample series of events that may result from methods of the flowchart ofFIG. 17. Of course, from the methods of the flowchart ofFIG. 17, a series of events may result that is different than the sample series of events ofFIG. 18. The events ofFIG. 18are shown along a time axis1812, with time intercepts that are not to scale. This portion of this description proceeds by referring to bothFIGS. 17 & 18.

It will be understood that flowchart1700can be performed for all possible cardiac arrhythmias, or only certain types of ones. In addition, flowchart1700can be performed for all possible shockable cardiac arrhythmias, or only certain types of ones For example, flowchart1700may be performed only for VT but not for VF, the reverse, and so on.

InFIG. 17, operation1710can be performed as described previously for operations410,610,710, etc. InFIG. 18, a timeline1810indicates that the physiological input starts being received at a time T1, by switching from a low value to a high value at that time.

Moreover, a measurement circuit such as measurement circuit220can be configured to render physiological inputs from the physiological signal of the patient monitored at operation1710ofFIG. 17. The physiological signal may be an ElectroCardioGram (ECG) signal, and the physiological inputs may be sections of an ECG waveform, taken at different times.

InFIG. 17, an operation1715can be performed as described previously for operations415,615,715, etc. While at operation1715no cardiac arrhythmia is being detected, execution can return to operation1710. This detection or not of a cardiac arrhythmia is shown inFIG. 18along a timeline1815. There is no detection while timeline1815has a low value. Detection may happen at time T2, at which time timeline1815changes to a high value. At that time, detection may have been performed using inputs received earlier.

It should be remembered thatFIGS. 17 & 18are from the point of view of the WCD system, its processor, and so on. Accordingly, while a cardiac arrhythmia may be detected at time T2, the onset or first time point of the cardiac arrhythmia may be a little earlier than that, and detection at time T2may be somewhat delayed from that onset or first time point.

Returning toFIG. 17, if detection happens at operation1715then, according to another operation1721, it can be determined whether or not the detected cardiac arrhythmia meets a validation criterion. The determination can be performed by a validation process that lasts 5-60 sec, or even longer. For example, the validation criterion may include that the detected cardiac arrhythmia needs to be maintained for the above mentioned threshold validation time of 5-60 sec, or even longer. InFIG. 18, this prolonged validation time lasts until time T25.

In some embodiments, the validation time is 25 sec, or even 35 sec, which is prolonged over the prior art ofFIG. 3C. This prolonged validation time can give a chance to the cardiac arrhythmia to self-terminate. In some embodiments, the type of the cardiac arrhythmia is also detected, and the validation lasts for such a prolonged time only for certain types of cardiac arrhythmias, e.g. for a ventricular tachycardia, but not for ventricular fibrillation. The prolonged validation period may therefore result in fewer instances when loud sounds such as alarms are output, and so on.

In embodiments, according to another operation1772, one of speakers271,272that is capable of outputting a loud sound is caused to output no sound louder than 58 decibel (db) as measured at a distance of, say, 2′ (i.e. 2 feet) from the speaker. This operation1772may be performed while operation1721is being performed, i.e. while the determination is being performed of whether or not the detected cardiac arrhythmia meets the validation criterion. In fact, no sound at all may be output while operation1721is being performed, when in fact this speaker may be capable of outputting a louder sound, as will be seen later in this description.

Subsequent operations may depend on the determination of operation1721, i.e. on whether or not the cardiac arrhythmia meets the validation criterion. According to another operation1725ofFIG. 17, if it is determined that the cardiac arrhythmia does not meet the validation criterion then the discharge circuit can be controlled to not cause a shock to be delivered responsive to the cardiac arrhythmia detected at operation1715.

Execution may then return to operation1710. It will be appreciated that, in some such instances where the detected cardiac arrhythmia does not meet the validation criterion, the speaker can be caused to output no sound at all, or no sound louder than 58 db, for another at least 10 minutes (min) after the determination has been performed. This additional time, when considered together with the time of operation1772can amount to a long quiet time for a cardiac arrhythmia that eventually self-terminated.

In parallel, inFIG. 18, operation1825reflects operation1725. If at operation1825it is determined that the cardiac arrhythmia does not meet the validation criterion, then a timeline1841for a loud sound shows no loud sound for a quiet time period that lasts from T1until at least time T26. This quiet time period can be the above-described 10 min. And, a timeline1897for a shock shows no shock for the same time period.

On the other hand, if at operation1725ofFIG. 17it is determined that the cardiac arrhythmia meets the validation criterion then, according to an operation1740, the speaker of operation1772may be caused to output a loud sound, for example a sound louder than 60 db, as measured at a distance of 2′ from the speaker. In this case, the speaker may be a siren, and be even louder than 60 db, such as over 100 db, given that the patient may be shocked and that no one should be touching them. Then, according to another operation1799, the discharge circuit can be further controlled so as to cause a shock to be delivered. Of course, additional operations may be performed, such as intervening warnings, an opportunity to cancel the shock, etc.

In parallel, inFIG. 18, if at operation1825it is determined that the cardiac arrhythmia meets the validation criterion, then an alternate timeline1842for a loud sound shows a loud sound1843, so as to alert bystanders. In addition, a timeline1898for a shock shows a shock1899.

Moreover, as seen above, some embodiments include another speaker, namely the other of271,272whose sound can be controlled as described in the above few paragraphs for the first speaker. In particular, the other speaker may be caused to output no sound louder than 58 db as measured at a distance of 2′ from the other speaker, or no sound at all, while the determination being performed of whether or not the detected cardiac arrhythmia meets the validation criterion.

In the above, the prolonged time period of validating the detected cardiac arrhythmia can be thought of as being part of a quiet time period. Indeed, while the WCD system may include a potentially loud siren, that siren can be kept from outputting a loud sound. Moreover, the prolonged time period of validating the detected cardiac arrhythmia can be further thought of as being part of a serene time period, because no defibrillation shock is being delivered. Each of the quiet time period and the serene time period can be considered to start at any suitable starting point, such as from when the cardiac arrhythmia was first detected, or when a determination started as to whether or not a validation criterion is met. And, if the arrhythmia self-terminates, the quiet time period and the serene time period can be extended for longer, e.g. 10 min or longer, as already mentioned above.

Additional measures can be taken for the patient's privacy and dignity. Just like with loud sounds, bright lights can be lit when an arrhythmia is detected and validated. Such lights can be lit only discreetly, or not lit up at all, however, if the arrhythmia is not so validated.

In some embodiments, the data about the quickly self-terminating arrhythmia may be transmitted by communication module290to a remote care giver for analysis, without outputting a loud sound. This may be performed with or without the prolonged validation period that was described with reference toFIG. 17. Examples are now described.

FIG. 19shows a flowchart1900for describing methods according to embodiments where data from self-terminating cardiac arrhythmias is transmitted by a WCD system without sounding loudly due to these cardiac arrhythmias. As withFIG. 17, flowchart1900can be performed for all possible cardiac arrhythmias, or only certain types of ones.

Flowchart1900has many elements that are similar to flowchart1700ofFIG. 17. Operations1910and1915may be performed similarly to operations1710,1715, respectively.

If detection happens at operation1915then, according to another operation1922, it can be determined whether or not the detected cardiac arrhythmia meets a validation criterion. The determination can be performed by a validation process that can last for any suitable duration. Operation1972may be performed similarly with operation1772.

Subsequent operations may depend on the determination of operation1922, i.e. on whether or not the cardiac arrhythmia meets the validation criterion. According to another operation1925ofFIG. 19, if it is determined that the cardiac arrhythmia does not meet the validation criterion then, according to an operation1976, communication module290can be caused to transmit data about the detected cardiac arrhythmia. This transmission may happen at any suitable time. In embodiments, the communication module is caused to transmit the data within 10 min of determining that the detected cardiac arrhythmia does not meet the validation criterion, or an even shorter time. This may give a remote care-giver the opportunity to call the patient, etc.

Furthermore, if it is determined that the detected cardiac arrhythmia does not meet the validation criterion, the discharge circuit can be controlled to not cause a shock to be delivered responsive to the cardiac arrhythmia detected at operation1915. Then execution may return to operation1910. It will be appreciated that, in some such instances where the detected cardiac arrhythmia does not meet the validation criterion, the speaker can be caused to output no sound at all, or no sound louder than 58 db, for another at least 10 min after the determination has been performed. This additional time, when considered together with the time of operation1972can amount to a long quiet time for a cardiac arrhythmia that eventually self-terminated.

On the other hand, if at operation1925ofFIG. 19it is determined that the cardiac arrhythmia meets the validation criterion, then operations1940,1999can be performed as was described for operations1740,1799, respectively.

Additional variations are possible, similarly with the embodiment ofFIG. 17. For example, any additional speaker(s) of the WCD system can be caused to output no sound louder than 58 db as measured at a distance of 2′ from the speaker, or no sound at all, while the determination of operation1922being performed. And, similarly with lights, which can be lit brightly for a validated arrhythmia, and discreetly or not at all for a non-validated arrhythmia. Moreover, operation1976may take place at one or more different and/or additional places in flowchart1900, for example after the YES decision of operations1915or1925, after operations1940or1999, etc.

Moreover, memory238ofFIG. 2can be configured to store data about the detected cardiac arrhythmia. In operations, data about the detected cardiac arrhythmia can be caused to be stored in memory238, etc.

In some embodiments, the data about the quickly self-terminating arrhythmia may be stored in memory238for later analysis, without outputting a loud sound. This may be performed with or without the prolonged validation period that was described with reference toFIG. 17, and with or without the transmission that was described with reference toFIG. 19. Examples are now described.

FIG. 20shows a flowchart2000for describing methods according to embodiments where data of some self-terminating cardiac arrhythmias is long-term stored by a WCD system, without sounding loudly due to these cardiac arrhythmias. As withFIGS. 17 and 19, flowchart2000can be performed for all possible cardiac arrhythmias, or only certain types of ones.

The operations of flowchart2000are now described for themselves, and also in conjunction with an operating example. In addition,FIG. 21is a time diagram of a sample series of events that may result from methods of the flowchart ofFIG. 20and from the operating example. Of course, from the methods of the flowchart ofFIG. 20, a series of events may result that is different than the sample series of events ofFIG. 21. The events ofFIG. 21are shown along a time axis2112, with intercepts that are not to scale. This portion of this description proceeds by referring to bothFIGS. 20 & 21.

InFIG. 20, operation2010can be performed as described previously for operations410,610,710, etc. InFIG. 21, a timeline2110indicates that the physiological input starts being received at a time T1, by switching from a low value to a high value.

Moreover, a measurement circuit such as measurement circuit220can be configured to render physiological inputs from the physiological signal of the patient monitored at operation2010ofFIG. 20. The physiological signal may be an ECG signal, and the physiological inputs may be sections of an ECG waveform, taken at different times.

In an operating example that starts being described now in parallel with flowchart2000, a first, then a second, then a third, and then a fourth physiological input become available due to operation2010. Accordingly, values V1, V2, V3, V4can be derived from the first, second, third, and fourth physiological inputs, respectively. InFIG. 21, a values timeline2111indicates the times when these values V1, V2, V3, V4are derived. Indeed, value V1is derived between T1and T2, value V2between T2and T18, value V3between T18and T19, and value V4after T19.

According to a next operation2016ofFIG. 20, next data can be stored in a memory of the WCD system, such as memory238ofFIG. 2. The term “next data” is general, and may apply to different data that is being made available, as this operation2016is repeated a number of times by being in a loop. The storing of operation2016can be over-writeable or longer term as may have been determined from a previous operation, and as will be seen later in this document.

In the operating example forFIG. 20, during the first time that operation2016is performed, the next data that is stored in the memory can be first values V1that are derived from the first physiological input made available due to operation2010. If the first physiological input is a section of an ECG waveform, then these first values V1can be time values of a section of the ECG waveform, or values representative of salient features of the ECG waveform section, and so on.

According to a next operation2017ofFIG. 20, it is inquired whether a cardiac arrhythmia of the patient is detected from the last-stored data. The last-stored data can be the data that was stored in the memory according to the latest storing operation, i.e. the last time that operation2016was executed. It will be understood that this can mean any cardiac arrhythmia, or only certain types of arrhythmias that are of potential interest, whether shockable or not. Actually, the type of this cardiac arrhythmia can be detected from the physiological input, either itself or from the data, values, etc. that are derived from the physiological input.

At operation2017, the answer can be yes or no. As seen briefly from timeline2115ofFIG. 21, in the operating example of this description the answer will be yes for values V2, and no for values V1, V3, V4. In other words, the cardiac arrhythmia of this example first manifested when values V2were derived, but self-terminated by the time values V3were derived.

If, at operation2017, the answer is no, then at a subsequent operation2018, the storing of the last-stored data is or becomes over-writable in the memory, so as to liberate memory space and conserve on requirements of memory. This operation2018may or may not be an explicit operation. For example, operation2018may be implemented implicitly by having operation2016be performed by writing to a memory, or portion of a memory, and then writing in the same memory over the data after some time, for example after two minutes.

In the operating example forFIG. 20, operation2018is performed the first time for stored values V1. The stored values V1are indicated inFIG. 20by an associated square V1; the fact that the storing of these values V1is now over-writable is indicated by showing square V1with dotted lines.

After operation2018, execution may return to operation2010, for ultimately receiving the next data that will be stored per operation2016. This closes the loop of operations2010,2016,2017,2018, for as long as no arrhythmia is being detected.

InFIG. 21, the detection of a cardiac arrhythmia is shown along a timeline2115. For as long as there is no detection, i.e. between times T1and T2, timeline2115has a low value.

In the operating example forFIG. 20, during the second time that operation2016is performed, the next data that is stored in the memory can be second values V2that are derived from the second physiological input made available due to operation2010. Moreover, as these second values V2become stored in the memory, at least some of the stored first values V1can become over-written by the storing of the second values V2. This over-writing can be permitted due to having performed operation2018earlier.

In this operating example, when operation2017is then repeated for these second values V2, the answer is yes: a cardiac arrhythmia of the patient is indeed detected. Actually, the cardiac arrhythmia can be detected from the second physiological input, either itself or from the second values that are derived from the second physiological input. These second values could be stored as per operation2016or not. InFIG. 21, the onset of the detection is shown at time T2, at which time timeline2115changes to a high value.

At operation2017ofFIG. 20, since the answer is yes then, according to a subsequent operation2019, the storing of the last-stored data is or becomes longer-term in the memory. Here the notion of “longer-term” is intended to distinguish from the over-writeable aspect of operation2018. At least some of the data with such longer-term storing will not be overwritten, and will thus be available for later review. Of course, they may become over-writable after the review, and so on.

This operation2019may or may not be an explicit operation. For example, operation2019may be implemented implicitly by having operation2016be performed using a memory that is not being re-written on, after some time. Or, operation2019may be performed explicitly by copying the relevant data to a different portion of the memory, as will be seen, for example, inFIG. 23.

InFIG. 21, the longer-term storing is shown by a timeline2119. In this example, and for this depiction, the longer-term storing is shown as coextensive with the detected arrhythmia of timeline2115, to better indicate the preference that what is stored is the data of the arrhythmia only. In embodiments, however, there can be a time delay from when the arrhythmia is first detected until the storing of the arrhythmia's data becomes longer-term. Plus, data that follows a self-terminating arrhythmia can give additional insights to reviewers, which is why it might be desirable to store also such data.

In the operating example forFIG. 20, operation2019is thus performed for stored values V2, because that is the last-stored data. The stored values V2are indicated inFIG. 20by an associated square V2; the fact that the storing of these values V2is now longer-term is indicated by showing square V2with solid lines.

InFIG. 20, according to a subsequent operation2066, next data is stored. Operation2066can be performed similarly to operation2016. The difference is that operation2066is performed after a cardiac arrhythmia has been detected at operation2017.

In the operating example forFIG. 20, the first time that operation2066is performed, the next data that becomes stored in the memory can be third values V3that are derived from the third physiological input made available due to operation2010. Moreover, as these third values V3become stored in the memory, at least some of the stored second values V2do not become over-written by the storing of the third values V3. In fact, in some embodiments, none of the stored second values V2become over-written by the storing of the third values V3. Such over-writing is prevented due to operation2019having been performed, which is responsive to the cardiac arrhythmia having been detected at operation2017.

InFIG. 20, according to a subsequent operation2025, it can be determined whether or not the cardiac arrhythmia detected at operation2017is validated. This validation operation2025may be implemented by determining whether or not the detected cardiac arrhythmia meets a validation criterion. There can be a number of such criteria for validation. In some embodiments, the validation criterion includes a determination of whether or not a cardiac arrhythmia is detected also from the subsequent third physiological input, or from at least some of the third values V3. It should be noted that the type of this cardiac arrhythmia sought to be detected for validation operation2025could be the same or different type than the cardiac arrhythmia detected at operation2017. In some embodiments, the determination of whether or not the detected cardiac arrhythmia meets the validation criterion is performed by a validation process that lasts for at least 25 sec or longer.

If at operation2025the answer is yes, then subsequent operations2040,2099may be implemented similarly to operations1740,1799, for sounding, then shocking, etc.

InFIG. 21, validation operation2125could result in different timelines2198(eventual shock), or2197(no shock for some time and from these inputs, since this arrhythmia was not validated). In this example, there is no shock for the times of values V1, V2, V3, V4.

If at operation2025ofFIG. 20the answer is no, then execution may proceed to operation2018, in which case the next data that was last-stored (value V3) become over-writable. Execution may then return to operation2010.

In the operating example forFIG. 20, the first time that operation2025is performed is for values V2, and the answer is indeed no. Execution then returns to operation2016for the third time. At that time, the next data that was last-stored per operation2066was third values V3, and may become over-writable per operation2018as evidenced by the associated dotted-lines square V3.

In the operating example forFIG. 20, during the third time that operation2016is performed, the next data that is stored in the memory can be fourth values V4that are derived from the fourth physiological input made available due to operation2010. Moreover, as these fourth values V4become stored in the memory, at least some of the stored second values V2do not become over-written by the storing of the fourth values V4. In fact, in some embodiments, none of the stored second values V2become over-written by the storing of the fourth values V4. Such over-writing is prevented due to operation2019having been performed, which is responsive to the cardiac arrhythmia having been detected at operation2017in connection with the second values V2.

In addition, at least some of the stored third values V3may optionally become over-written by the storing of the fourth values V4, responsive to having determined that the detected cardiac arrhythmia is not validated at operation2025. Such can become enabled if third values V3becomes over-writable, as per the above.

It will be appreciated that, in some such instances where the cardiac arrhythmia detected at values V2does not meet the validation criterion per values V3, the speaker can be caused to output no sound at all, or no sound louder than 58 db, for another at least 10 min after the determination has been performed that the detected cardiac arrhythmia does not meet its validation criterion. This time can amount to a long quiet time for a cardiac arrhythmia that eventually self-terminated.

Sample results are now described. It will be recognized that these results correspond to the operating example forFIG. 20, but use different embodiments for the memory configuration.

FIG. 22shows a table whose first column shows values V1, V2, V3, V4described above, as they are being received or derived. For each of these values V1, V2, V3, V4there is a row of results. In this example, according to the next column, an arrhythmia is detected for value V2, but not for values V1, V3, V4. In this example, according to the yet next column, it is meaningful to validate the arrhythmia, only for values V2; and this arrhythmia is not validated because an arrhythmia is not detected from the subsequent values V3, as shown by arrow2225.

In the example ofFIG. 22, according to the next column, there is no loud sound output responsive to any of values V1, V2, V3, V4. According to a comment2219, this is true even though value V2had an arrhythmia, because that arrhythmia was not eventually validated.

In the example ofFIG. 22, a memory2238of the WCD system according to embodiments could be memory238. In the last column, an evolution is shown of a map of memory2238, responsive to received values V1, V2, V3, V4becoming stored. A previous value PV is stored longer-term, and is not over-written. According to a comment2219, values V2are not overwritten so as to be preserved for subsequent review, while values V1, V3, etc. are over-written in whole or in part by the subsequently received values, so as to conserve space in memory2238.

In another example,FIG. 23shows a table whose first four columns are the same as those ofFIG. 22. Values V2do not meet the validation criterion, because an arrhythmia is not detected from subsequent values V3, as shown by arrow2325. According to a comment2319, there is no loud sound output responsive to value V2, because its detected arrhythmia was not eventually validated.

In the example ofFIG. 23, a memory2338of the WCD system according to embodiments could be memory238. Memory2338has a long term portion LTP and a short term portion STP. Second values V2can be written in the long term portion responsive to the cardiac arrhythmia having been detected from the second physiological input. In fact, second values V2can be initially written in the short term portion, and then second values V2can become written to the long term portion by being copied from the short term portion, responsive to the cardiac arrhythmia having been detected from the second physiological input.

Similarly withFIG. 22, the last column ofFIG. 23shows an evolution of a map of memory2338, responsive to received values V1, V2, V3, V4becoming stored. A previous value PV is stored in the long term portion, and is thus not over-written. Incoming values V1, V2, V3, V4are written in the short term portion, and then over-written by the subsequently incoming value, so as to conserve space. This short term portion may be a buffer that holds a time duration of data lasting for a suitable time, such as 2 minutes. Second values V2can be copied in the long term portion from the short term portion, responsive to the cardiac arrhythmia having been detected from the second physiological input so as to be preserved for subsequent review, as shown by comment2319.

The long-term stored values PV, V2permit review of events, when the memory is downloaded later for study. In addition, for self-terminating events, the patient may have been spared the embarrassment of a loud alarm like a siren, if they do not respond quickly enough with the cancel switch, and so on.

FIG. 24shows a flowchart2400for describing methods according to embodiments where data from self-terminating cardiac arrhythmias is transmitted by a WCD system without sounding loudly due to these cardiac arrhythmias. As withFIG. 17, flowchart2400can be performed for all possible cardiac arrhythmias, or only certain types of ones.

In addition,FIG. 25is a time diagram of a sample series of events that may result from methods of the flowchart ofFIG. 24. Of course, from the methods of the flowchart ofFIG. 24, a series of events may result that is different than the sample series of events ofFIG. 25. The events ofFIG. 25are shown along a time axis2512, with time intercepts that are not to scale. This portion of this description proceeds by referring to bothFIGS. 24 & 25.

InFIG. 24, according to an operation2410, physiological inputs from an ECG signal of the patient are monitored. InFIG. 25, a timeline2511indicates that the physiological input from the ECG starts being received at a time T1, by switching from a low value to a high value.

InFIG. 24, an operation2415can be performed as described previously for operations415,615,715,1715, etc. While at operation2415no cardiac arrhythmia is being detected, execution can return to operation2410. This detection or not of a cardiac arrhythmia is shown inFIG. 25along a timeline2515. There is no detection while timeline2515has a low value. Detection may happen at time T2, at which time timeline2515changes to a high value. At that time, detection may have been performed using inputs received earlier.

It should be remembered thatFIGS. 24, 25are from the point of view of the WCD system, its processor, and so on. Accordingly, while a cardiac arrhythmia may be detected at time T2, the onset or first time point of the cardiac arrhythmia may be a little earlier and detection may be somewhat delayed. In the particular case of this example, a time line2514shows a first time point of the cardiac arrhythmia as time TFTP, which is somewhat before time T2. (For example, in the prior art ofFIG. 3B, this first time point seems to occur at time TB.) In some embodiments, this first time point of the cardiac arrhythmia TFTP is identified explicitly in the ECG signal.

Returning toFIG. 24, if detection happens at operation2415, then there can be waiting for up to a confirmation period to determine whether or not the detected cardiac arrhythmia has self-terminated. This is expressed inFIG. 24as a waiting loop formed by operations2419,2422&2472. It will be recognized that this waiting loop can be considered to be a validation operation2421, and that the confirmation period is a type of validation period.

In operation2421, according to operation2422, it is determined whether the confirmation period has passed. In some embodiments, the confirmation period is defined as starting from a first time point of the cardiac arrhythmia, and lasting at least 35 sec, or longer, such as 45 sec, 55 sec, etc. It will be appreciated that this confirmation period is substantially longer than the prior art ofFIG. 3BandFIG. 3C, thus giving a detected cardiac arrhythmia a better chance to self-terminate.

If at operation2422the answer is no, then there is waiting. During the waiting, according to a next operation2472the speaker is caused to output no sound louder than 62 db, as measured at a distance of 2′ from the speaker. In some embodiments, the speaker is in fact caused to output no sound during this waiting, which means not a loud sound for bystanders, not an audible sound for the rescuer, etc.

According to a next operation2419it is determined whether or not the cardiac arrhythmia is still being detected from subsequent physiological inputs. If not, it means that the cardiac arrhythmia has self-terminated within the confirmation period, and execution exits the waiting loop to return to operation2410. In such embodiments, the discharge circuit can be controlled to not cause a shock to be delivered responsive to the detected cardiac arrhythmia.

It will be appreciated that, in some such instances where the detected cardiac arrhythmia exits the waiting loop before the confirmation period, the speaker can be caused to output no sound at all, or no sound louder than 58 db, for another at least 10 min after an end of the confirmation period. This can amount to a long quiet time for a cardiac arrhythmia that eventually self-terminated.

If at operation2419the cardiac arrhythmia is still being detected, then execution proceeds again to operation2422of the waiting loop. If the confirmation period has passed, then the cardiac arrhythmia has been validated. Then, according to an operation2440, the speaker can be caused to output a sound. In some embodiments, the sound is louder than 50 db, as measured at a distance of 2′ from the speaker. In some instances, audible sound is required to output verbal warnings to the wearer, for example at a sound intensity of a conversation, of perhaps around 55 db at 2′. In some instances, loud sound is required, to output a warning to bystanders that something extraordinary is going to happen. In such instances, that loud sound can be an alarm or even a siren, in which case it might be louder than 62 db as measured at a distance of 2′ from the speaker. And, according to another operation2499, the discharge circuit can be controlled to cause the shock to be delivered.

InFIG. 25, the confirmation period is shown along a time line2522, lasting between TFTP and T28. A decision diamond2521shows that, if yes and the cardiac arrhythmia is still detected, then there is a sound time line2542showing a sound2543, and a shock time line2598showing a shock2599. Of course, sound2543can be an audible sound, a loud sound as per the above, etc.

If the answer to decision diamond2521is no, then there can be two branches. In one branch2519while the cardiac arrhythmia is still being detected, then there is a loud sound time line2572showing no loud sound, and a shock time line2588showing no shock. These two time lines2572,2588could reach all the way to time T28with no event while still part of the confirmation period; beyond time T28, however, they might continue as time lines2542,2598respectively.

If the answer to decision diamond2521is no, then there is another branch2571, where the cardiac arrhythmia is no longer being detected. Then then there is a loud sound time line2570showing no loud sound, and a shock time line2597showing no shock.

Additional embodiments may include what was described above with reference to additional speakers, and so on.

In the methods described above, each operation can be performed as an affirmative step of doing, or causing to happen, what is written that can take place. Such doing or causing to happen can be by the whole system or device, or just one or more components of it. It will be recognized that the methods and the operations may be implemented in a number of ways, including using systems, devices and implementations described above. In addition, the order of operations is not constrained to what is shown, and different orders may be possible according to different embodiments. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Moreover, in certain embodiments, new operations may be added, or individual operations may be modified or deleted. The added operations can be, for example, from what is mentioned while primarily describing a different system, apparatus, device or method.

A person skilled in the art will be able to practice the present invention in view of this description, which is to be taken as a whole. Details have been included to provide a thorough understanding. In other instances, well-known aspects have not been described, in order to not obscure unnecessarily this description. Plus, any reference to any prior art in this description is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms parts of the common general knowledge in any country or any art.

This description includes one or more examples, but this fact does not limit how the invention may be practiced. Indeed, examples, instances, versions or embodiments of the invention may be practiced according to what is described, or yet differently, and also in conjunction with other present or future technologies. Other such embodiments include combinations and sub-combinations of features described herein, including for example, embodiments that are equivalent to the following: providing or applying a feature in a different order than in a described embodiment; extracting an individual feature from one embodiment and inserting such feature into another embodiment; removing one or more features from an embodiment; or both removing a feature from an embodiment and adding a feature extracted from another embodiment, while providing the features incorporated in such combinations and sub-combinations.

In this document, the phrases “constructed to” and/or “configured to” denote one or more actual states of construction and/or configuration that is fundamentally tied to physical characteristics of the element or feature preceding these phrases and, as such, reach well beyond merely describing an intended use. Any such elements or features can be implemented in a number of ways, as will be apparent to a person skilled in the art after reviewing the present disclosure, beyond any examples shown in this document.

Any and all parent, grandparent, great-grandparent, etc. patent applications, whether mentioned in this document or in an Application Data Sheet (“ADS”) of this patent application, are hereby incorporated by reference herein as originally disclosed, including any priority claims made in those applications and any material incorporated by reference, to the extent such subject matter is not inconsistent herewith.

In this description a single reference numeral may be used consistently to denote a single item, aspect, component, or process. Moreover, a further effort may have been made in the drafting of this description to use similar though not identical reference numerals to denote other versions or embodiments of an item, aspect, component or process that are identical or at least similar or related. Where made, such a further effort was not required, but was nevertheless made gratuitously so as to accelerate comprehension by the reader. Even where made in this document, such a further effort might not have been made completely consistently for all of the versions or embodiments that are made possible by this description. Accordingly, the description controls in defining an item, aspect, component or process, rather than its reference numeral. Any similarity in reference numerals may be used to infer a similarity in the text, but not to confuse aspects where the text or other context indicates otherwise.

The claims of this document define certain combinations and subcombinations of elements, features and steps or operations, which are regarded as novel and non-obvious. Additional claims for other such combinations and subcombinations may be presented in this or a related document. These claims are intended to encompass within their scope all changes and modifications that are within the true spirit and scope of the subject matter described herein. The terms used herein, including in the claims, are generally intended as “open” terms. For example, the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” etc. If a specific number is ascribed to a claim recitation, this number is a minimum but not a maximum unless stated otherwise. For example, where a claim recites “a” component or “an” item, it means that it can have one or more of this component or item.