A medical device is configured to detect an atrial tachyarrhythmia episode. The device senses a cardiac signal, identifies R-waves in the cardiac signal attendant ventricular depolarizations and determines classification factors from the R-waves identified over a predetermined time period. The device classifies the predetermined time period as one of unclassified, atrial tachyarrhythmia and non-atrial tachyarrhythmia by comparing the determined classification factors to classification criteria. A classification criterion is adjusted from a first classification criterion to a second classification criterion after at least one time period being classified as atrial tachyarrhythmia. An atrial tachyarrhythmia episode is detected by the device in response to at least one subsequent time period being classified as atrial tachyarrhythmia based on the adjusted classification criterion.

An external defibrillator system includes one or more compression sensors; one or more physiological sensors; and at least one processor. The at least one processor is configured to: receive and process chest compression signals and physiological signals from the sensors, determine values for chest compression depth and/or chest compression rate based on the received chest compression signals, determine a trend of at least one physiological parameter over a period comprising multiple chest compressions based on the received physiological signals, adjust a target chest compression depth and/or target chest compression rate based on the determined trend of the at least one physiological parameter, compare the determined values for chest compression depth and/or chest compression rate to the adjusted target compression depth and/or the adjusted target compression rate, and provide feedback about the quality of chest compressions performed on the patient.

A system includes a signal generator, configured to pass a generated signal, which has two different generated frequencies, through a circuit including an intrabody electrode. The system further includes a processor, configured to identify, while the generated signal is passed through the circuit, a derived frequency, which is derived from the generated frequencies, on the circuit, and to generate, in response to identifying the derived frequency, an output indicating a flaw in the electrode. Other embodiments are also described.

An apparatus and method is provided for a defibrillator that specifies treatment protocols in terms of number of chest compressions instead of time intervals. The defibrillator includes a connection port that is configured to attach with a plurality of electrodes that are capable of delivery of a defibrillation shock and/or sensing one or more physical parameters. An energy storage device capable of storing a charge is attached to the plurality of electrodes. A controller is coupled to the plurality of electrodes and the energy storage device, the controller is configured to provide CPR chest compression instructions in terms of the numbers of CPR chest compressions.

A system including a sensor interface coupled to a processor. The sensor interface is configured to receive and process an analog electrocardiogram signal of a subject and provide a digitized electrocardiogram signal sampled over a first time period and a second time period that is subsequent to the first time period. The processor is configured to receive the digitized electrocardiogram signal, to analyze a frequency domain transform of the digitized electrocardiogram signal sampled over the first and second time periods and determine first and second metrics indicative of metabolic state of a myocardium of the subject during the first and second time periods, respectively, to compare the first and second metrics to determine whether the metabolic state of the myocardium of the subject is improving, and to indicate administration of an intervention to the subject in response to a determination that the metabolic state is not improving.

A defibrillator and method for using a defibrillator which adopts an ECG analysis algorithm that can detect a cardiac arrhythmia in the presence of noise artifact induced by cardio pulmonary resuscitation (CPR) compressions. The apparatus and method offers guidance throughout a cardiac rescue protocol involving both defibrillation shocks and CPR that improves the effectiveness of the rescue, resulting in more CPR “hands-on” time, better treatment of refibrillation, and reduced transition times between CPR and electrotherapy.

An emergency medical device (20) (e.g., an external defibrillator/monitor) employing an emergency medical subsystem (21) for executing an emergency medical procedure (e.g., a monitoring subsystem (21) and a therapy subsystem (21)), and an emergency medical controller (23) for controlling an activation of the emergency medical subsystem (21). The subsystem (21) includes one or more operational components (22). In operation, the controller (23) conditionally actuates a device readiness indicator (24) (e.g., auditory or visual) indicative of an operational readiness of the operational component(s) (22), and conditionally actuates a failure warning indicator (25) (e.g., auditory or visual) indicative of a pending failure of the operational readiness of the operational component(s) (22). The failure warning indicator (25) may be actuated based on a predictive failure analysis of a premature degradation of the operational component(s) (22), a repeated occurrence of error conditions of the operational component(s) (22) (particularly recoverable error conditions), and a shortened reliable life of the operational component(s) (22).

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.

A system employing an ECG monitor (40) and a defibrillation advisory controller (20). In operation, the ECG monitor (40) monitors a cardiac rhythm of a patient, and the defibrillation advisory controller (20) generates a defibrillation advisory based on a cardiac rhythm status and a metabolic cardiac status of the patient, and optionally further based on an electrical cardiac status of the patient. The controller (20) derives the cardiac rhythm status as monitored by ECG monitor (40), and the optional electrical cardiac status inclusive of the cardiac rhythm monitored by the ECG monitor (40), and derives the metabolic cardiac status exclusive of the cardiac rhythm monitored by the ECG monitor (40). The controller (20) may compute or receive metabolic cardiac data indicative of the metabolic cardiac status (e.g., incorporating or coupled to a user input device (50), a breath analyzer (60) and a blood analyzer (70)), and compares the metabolic cardiac data to a metabolic cardiac threshold (fixed or variable) and/or monitors a trend of the metabolic cardiac data to derive the metabolic cardiac status of the patient.

Method and system for determining an atrial contraction timing fiducial in a leadless cardiac pacemaker system is disclosed. An electrical cardiac signal associated with an atrial contraction of the patient's heart and a mechanical response to the atrial contraction of a patient's heart are used to determine an atrial contraction timing fiducial. A ventricle pacing pulse may then be generated an A-V delay after the atrial contraction timing fiducial.