Abstract: A wearable cardioverter defibrillator (WCD) comprises a plurality of electrocardiography (ECG) electrodes, a right-leg drive (RLD) electrode, and a plurality of defibrillator electrodes to contact the patient's skin when the WCD is delivering therapy to the patient, a preamplifier coupled to the ECG electrodes and the RLD electrode to obtain ECG data from the patient as one or more ECG vectors, a processor to receive ECG data from the preamplifier and an abort signal from a user interface, an isolation barrier to isolate the preamplifier from the processor, and a high voltage subsystem to provide a defibrillation voltage to the patient through the defibrillator electrodes in response to a shock signal received from the processor. A shock is provided when an abort signal is not received within a predetermined time period of a shock criterion being met. Less than one false alarm occurs every ten patient-days.

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, generate a supraventricular (SV) template for SV complexes in the QRS complexes, identify SV complexes in the QRS complexes using the template, identify normal sinus rhythm (NSR) complexes in the segment of the ECG signal, obtain an atrial template for atrial waveforms in the NSR complexes, measure a range of a P-wave of the atrial waveforms from the NSR complexes, save the measured P-waves, and classify the identified SV complexes as either atrial fibrillation (AF) or supraventricular tachycardia (SVT) using the atrial template. Other examples and related methods are also disclosed herein.

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: In one embodiment, a carrying case for a wearable cardioverter defibrillator (WCD) is described. The carrying case includes a container with a front wall, a rear wall, and a gusset coupling the front wall and the rear wall. The carrying case also includes each of the front wall and rear wall including multiple fabric layers. The carrying case also includes two connection points inset from an edge of the rear wall. The carrying case also includes an adjustable strap removably coupled to the connection points, the adjustable strap configured to be worn in various configurations on a body of a patient.

Abstract: A wearable cardioverter defibrillator (WCD) having a processor configured to receive a signal indicating a position and/or movement of the ambulatory patient while the ambulatory patient is wearing the support structure receive the ECG signal, determine from an ECG signal whether a shock criterion is met, determine a confirmation time period and/or a response time period based on the position and/or movement of the ambulatory patient, determine from the ECG signal whether the shock criterion is met after the confirmation time period has elapsed, cause the user interface to generate the shock alert signal based on the shock criterion determined after the confirmation time period has elapsed, and control the discharge circuit to discharge the stored electrical charge when a predetermined time period has elapsed after the shock alert signal.

Abstract: A wearable cardioverter defibrillator (“WCD”) latching connector system includes a receptacle positioned within a WCD monitor, and a connector configured to removably engage the receptacle.

Abstract: In embodiments, a wearable cardiac defibrillation (WCD) system includes one or more flexible ECG electrodes. The WCD system may have a support structure that is dimensioned to be worn so as to press the electrodes towards the body of the patient. The electrodes may be made from appropriate material so as to flex in order to match a contour of the body of the patient. An advantage over the prior art is that the flexible electrode may make better electrical contact with the patient's skin, and therefore provide a better ECG signal for the WCD system to perform its diagnosis.

Abstract: Technologies and implementations for a wearable medical device (WMD). The WMD includes electrocardiogram (ECG) electrodes and/or therapy electrodes having resistor components formed utilizing resistive ink.

Abstract: In one embodiment, a method to alert a user of a wearable cardioverter defibrillator (WCD) is described. The method includes determining when a system issue is resolved and issuing an alert when the system issue is resolved. In some embodiments, the method may detect the system issue and issuing a system alert based at least in part on the system issue. The method may then monitor a status of the system issue. In some instances, the method may detect an abnormality in system operation sand determine a severity rating for the abnormality. The method may determine if the abnormality satisfies a time duration threshold based at least in part on the severity rating.

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 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 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: 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 (WCD) having a processor configured to receive a signal indicating a position and/or movement of the ambulatory patient while the ambulatory patient is wearing the support structure receive the ECG signal, determine from an ECG signal whether a shock criterion is met, determine a confirmation time period and/or a response time period based on the position and/or movement of the ambulatory patient, determine from the ECG signal whether the shock criterion is met after the confirmation time period has elapsed, cause the user interface to generate the shock alert signal based on the shock criterion determined after the confirmation time period has elapsed, and control the discharge circuit to discharge the stored electrical charge when a predetermined time period has elapsed after the shock alert signal.

Abstract: In embodiments, a wearable medical system (“WMS”) implements a wearable cardioverter defibrillator (“WCD”) that senses and samples a patient's ECG signals. In a regular mode, the WMS produces a first set of ECG values, which can be the minimum needed for a WCD operation. In a second or rich mode of operation, the WMS produces a second set of ECG values, more numerous than the first set. The rich mode can be implemented by sampling the ECG signal faster, and/or not ignoring ECG signals in channels that are ignored in the regular mode, and/or by having more ECG sensing electrodes than the minimum needed for the WCD operation. The WMS stores the first set and the second set, and uses either one to determine whether defibrillation is needed. In addition, it communicates them to another device. In embodiments, support structures for a WMS have multiple ECG electrodes for just sensing.

Abstract: A Wearable Medical System (WMS) that implements a wearable cardioverter defibrillator (WCD), includes a microphone and related improvements. The microphone can be on the same dongle as the cancel switch of the WCD. A user trigger module may permit the patient to perform a deliberate act and, in response, the system may start recording audio from the ambient sounds, including their own voice, and/or start recording the ECG. The deliberate act may even be a voice command by the patient that is parsed by a voice recognition module. The WMS may continuously record audio and then continuously discard it, and further stop the discarding if it detects a recording trigger. The WMS may create an exportable computer file that has audio-related data, which can have playable sound data or transcribed voice data.

Abstract: In embodiments, a wearable cardiac defibrillation (WCD) system includes one or more flexible ECG electrodes. The WCD system may have a support structure that is dimensioned to be worn so as to press the electrodes towards the body of the patient. The electrodes may be made from appropriate material so as to flex in order to match a contour of the body of the patient. An advantage over the prior art is that the flexible electrode may make better electrical contact with the patient's skin, and therefore provide a better ECG signal for the WCD system to perform its diagnosis.

Abstract: In embodiments a WCD system is worn and/or carried by an ambulatory patient. The WCD system analyzes an ECG signal of the patient, to determine whether or not the patient should be given an electric shock to restart their heart. If so, then the WCD system first gives a preliminary alarm to the patient, asking them to prove they are alive if they are. The WCD system further determines whether the ECG signal contains too much High Amplitude (H-A) noise, which can distort the analysis of the ECG signal. If too much H-A noise is detected for a long time, the WCD system may eventually alert the patient about their activity, so that the ECG noise may be abated. The WCD system may even pause the analysis of the ECG signal, so that there will be no preliminary alarms that could be false until the ECG noise is abated.