Abstract: Disclosed are embodiments directed to security methods applied to connections between components in a distributed (networked) system including medical and non-medical devices, providing secure authentication, authorization, patient and device data transfer, and patient data association and privacy for components of the system.

Abstract: A wearable cardioverter defibrillator monitor case includes a housing configured to surround a defibrillator electronics assembly, a front cover removably attachable to the housing, and a rear cover removably attachable to the housing. The wearable cardioverter defibrillator case has a shock indicator positioned on the housing at an interface between the housing and the front cover.

Abstract: Embodiments of a wearable cardioverter defibrillator (WCD) system include a support structure for wearing by an ambulatory patient, a posture detector and at least one processor. When worn, the support structure maintains electrodes on the patient's body, and using the posture detector and the patient's ECG received via the electrodes, the processor determines the patient's posture, formulates posture-based templates of QRS complexes, and the patient's heart rate. The processor can use these determinations to distinguish between VT and SVT and make no-shock, and shock decisions.

Abstract: A WCD system is configured to monitor various characteristics of the WCD system including about the patient. The information collected by the WCD is generally referred to as “patient information.” The WCD system is further configured to transmit certain of the patient information to different recipients based on predetermined profiles with which one or more of the recipients is associated. In various embodiments, different sets or subsets of the patient information may be sent to different recipients.

Abstract: A Wearable Cardiac Defibrillator (WCD) system is configured to be worn by a patient who carries a mobile communication device. The mobile communication device has a user interface that is configured to enable the patient to enter wireless inputs. The WCD system includes a communication module that is configured to establish a local comlink with the mobile communication device. The WCD system also includes a tethered action unit that has a user interface configured to enable the patient to enter action inputs. The WCD system can perform some of its functions in response to the action inputs or to the wireless inputs. Since the wireless inputs can be provided from the mobile communication device instead of the action unit, the patient is less likely to attract attention when entering them, and thus exhibit better compliance.

Abstract: In embodiments, an external defibrillator has an electrical circuit with a special output stage for the high-voltage defibrillation pulse. The output stage includes switches that can turn on for delivering the pulse, and off during all other times. The output stage also includes a diverting resistance to divert electrical current that could leak into the patient while a capacitor is being charged. An optional detector may notify if a component is malfunctioning. An advantage can be that an external defibrillator may be created according to embodiments that uses, in its output stage, semiconductor switches instead of relays. As semiconductor switches weigh less and occupy less volume than relays, an external defibrillator according to embodiments may have less weight and volume. Especially in wearable defibrillator applications, less weight means less effort to carry and less volume means easier concealment under clothing.

Abstract: In one embodiment, a method to detect noise levels in electrocardiogram (ECG) signals is described. The method includes connecting to at least three sensing electrodes and obtaining a signal from each of the at least three sensing electrodes. The method also includes defining at least three channels between the at least three electrodes. The method includes calculating a morphological similarity value of at least one combination of the at least three channels based at least in part on the obtained signal from each of the at least three sensing electrodes and determining a noise level based at least in part on the calculated morphological similarity value.

Abstract: In one embodiment, a method to determine reliable electrocardiogram (ECG) signal is described. The method includes receiving at least one ECG signal for a period of time from a patient. The method also includes analyzing the at least one ECG signal to determine a first heart rate using a first method and analyzing the at least one ECG signal to determine a second heart rate using a second method different from the first method. The method includes comparing the first and second heart rates to each other and classifying the at least one ECG signal as reliable when a reliability threshold is satisfied.

Abstract: A wearable cardiac defibrillator (“WCD”) system may include a support structure that a patient can wear, an energy storage module that can store an electrical charge, and a discharge circuit that can discharge the electrical charge through the patient so as to shock him or her, while the patient is wearing the support structure. Embodiments may actively take into account bystanders, both to protect them from an inadvertent shock, and also to enlist their help. In some embodiments, the WCD system includes a speaker system and a memory. Prompts have been saved in advance in the patient's own voice, and stored in the memory. In case of an emergency, the prompts may be played by the speaker system in the patient's own voice, and heard by a bystander.

Abstract: A data file system includes one or more files about a patient wearing a wearable cardiac defibrillator (WCD) system that has been assigned to them. The one or more files contain at least one patient identifier of the patient, compliance data about a history of the patient's wearing the WCD system, and possibly other data. The data file system can be accessed through a communication network when the patient uses a communication device. When so accessed, some of the contents can be viewed on a screen of the device, for example in the form of a website. In embodiments, the health care provider and friends and family can view such data and even enter inputs, which may create a situation that motivates the patient to comply better.

Abstract: A wearable cardioverter defibrillator (WCD) including a support structure configured to be worn by an ambulatory patient, an energy storage module configured to store an electrical charge, a discharge circuit coupled to the energy storage module, electrodes configured to render an electrocardiogram (ECG) signal of the patient while the patient is wearing the support structure, a user interface configured to output an alarm in response to a noise alarm signal, and a processor. The processor is configured to receive the ECG signal, determine whether noise is present on the ECG signal, determine from the ECG signal whether a shock criterion is met, and cause the user interface to generate the noise alarm signal when the noise is present on the ECG signal and the shock criterion is met and not generate the noise alarm signal when noise is present on the ECG signal and the shock criterion is not met.

Abstract: In one example, an apparatus of a wearable cardioverter defibrillator (WCD) system comprises a support structure wearable by a patient, a plurality of electrocardiogram (ECG) electrodes to obtain an ECG signal, a processor to receive and analyze the ECG signal of the patient, wherein the processor is configured to monitor four or more channels of the ECG signal, a high voltage subsystem coupled with defibrillation electrodes configured to be coupled with patient, wherein processor is configured to cause the high voltage subsystem to apply a therapeutic shock to the patient through the defibrillation electrodes in response to a shockable event detected by the processor from the ECG signal. The processor measures a peak-to-peak amplitude of QRS complexes of the ECG signal, and detects asystole in the patient when the peak-to-peak amplitude of one or more QRS complexes is less than an asystole threshold. Other examples and related methods are disclosed herein.

Abstract: In one example, a cardiac monitoring system, comprises a processor to receive a segment of an electrocardiogram (ECG) signal of a patient, and a memory to store the segment of the ECG. The processor is configured to identify QRS complexes in the segment of the ECG signal, compare the QRS complexes in the segment to the other QRS complexes in the segment to identify a main template QRS complex, identify the QRS complexes in the segment that are similar to the main template, determine RR intervals between consecutive similar QRS complexes to calculate RR variability in the RR intervals, and detect atrial fibrillation (AF) in the segment when RR variability is greater than a threshold value. Other examples and related methods are also disclosed herein.

Abstract: Embodiments of this disclosure are directed to a wearable cardioverter defibrillator (“WCD”) system design in which a WCD implements an alert prioritization scheme to provide the patient with feedback in an order that is less likely to cause confusion. Different conditions (e.g., device status, equipment condition, or physiologic condition) are prioritized based on an analysis of severity of the condition and timeliness of user action needed. The prioritization scheme defines what alert, if any, is presented to the user by the WCD system as a result of various conditions. Generally stated, an alert for the highest priority condition currently detected is presented to the user and maintained until that condition either changes or becomes surpassed in the prioritization scheme.

Abstract: A Wearable Cardiac Defibrillator (WCD) system is configured to be worn by a patient who carries a mobile communication device. The mobile communication device has a user interface that is configured to enable the patient to enter wireless inputs. The WCD system includes a communication module that is configured to establish a local commlink with the mobile communication device. The mobile communication device can receive shock data from the WCD system after a shock is applied to the patient, can determine a location of the WCD system based on a location of the mobile communication device, and can transmit the shock data and the location data to a central call center of a remote assistance system. The central call center can enhance the operation of the WCD system by contacting the patient, contacting and emergency contact, and/or contacting a local emergency medical system (EMS).

Abstract: Embodiments of a wearable cardioverter defibrillator (WCD) system include a support structure for wearing by an ambulatory patient and at least one processor. When worn, the support structure maintains electrodes on the patient's body, and using the patient's ECG received via the electrodes, the processor determines widths of the QRS complexes, consistency of the QRS complexes, and/or heart rate and uses these determinations to make no-shock, delay-shock, and shock decisions. Shock decisions can be made for heart rates lower than a VF threshold.

Abstract: In embodiments, a WCD system includes electrodes with which it senses an ECG signal of the patient. A processor may detect sequential peaks within the ECG signal, measure durations of time intervals between the peaks, including between non-sequential peaks, and identify a representative duration that best meets a plausibility criterion. The plausibility criterion may be that the representative duration is the one that occurs the most often, i.e. is the mode. Then a heart rate can be computed from a duration indicated by the representative duration and, if the heart rate meets a shock condition, the WCD system may deliver a shock to the patient. An advantage can be that the representative duration can be close to a good R-R interval measurement of a patient, notwithstanding noise in the ECG signal that is in the shape of peaks.

Abstract: In embodiments, a wearable cardioverter defibrillator (WCD) system includes electrodes that render an ECG signal of the patient, and a processor that receives ECG data are derived from the rendered ECG signal. The processor may filter the received ECG data with a matched difference filter to detect QRS complexes, and compute a heart rate from the detected QRS complexes. The matched difference filter itself can have coefficient values associated with a baseline QRS complex, which improves detection.

Abstract: A wearable cardiac defibrillator (“WCD”) system may include a support structure that a patient can wear, an energy storage module that can store an electrical charge, and a discharge circuit that can discharge the electrical charge through the patient so as to shock him or her, while the patient is wearing the support structure. Embodiments may actively take into account bystanders, both to protect them from an inadvertent shock, and also to enlist their help. In some embodiments the WCD system includes a speaker system that transmits a sound designed to assist a bystander to perform CPR. Optionally CPR chest compressions received by the patient can be further detected, and feedback can be given. In embodiments, a WCD system may include a user interface that can be controlled to output CPR prompts tailored to a skill level of the bystander.

Abstract: A wearable cardioverter defibrillator monitor case includes a housing configured to surround a defibrillator electronics assembly, a front cover removably attachable to the housing, and a rear cover removably attachable to the housing. The wearable cardioverter defibrillator case has a shock indicator positioned on the housing at an interface between the housing and the front cover.