A defibrillator (AED) and method for using a defibrillator using two different ECG analysis algorithms which work sequentially to improve the accuracy of AED shock decisions. A first algorithm, such as (ART), is particularly suited for analysis in the presence of CPR periods. A second algorithm, such as (PAS), is particularly suited for analysis during hands-off periods. The AED switches algorithms depending on the period and on the current analysis of the cardiac rhythm. The inventions thus provide an optimized ECG analysis scheme in a manner 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.

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.

A wearable medical includes a walking detector module with a motion sensor that is configured to detect when the patient is walking or running. In embodiments, a parameter (referred to herein as a Bouncy parameter) is determined from Y-axis acceleration measurements. In some embodiments, the Bouncy parameter is a measurement of the AC component of the Y-axis accelerometer signal. This detection can be used by the medical device to determine how and/or whether to provide treatment to the patient wearing the medical device. For example, when used in a WCD, the walking detector can prevent false alarms because a walking patient is generally conscious and not in need of a shock.

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.

An electrode for long term wear includes a conductive mesh configured to disperse a therapeutic current across a surface area of the electrode, and a conductive adhesive material configured to conduct the therapeutic current from the conductive mesh in a direction substantially orthogonal to the surface area of the electrode. The conductive adhesive material is configured to be semi-conductive in a direction substantially lateral to the surface area of the electrode. The conductive adhesive material includes at least one of microscopic or nano-scale conductive particles or fibers of materials.

A medical device uses UWB units to infer a position of an adjunct positioned in proximity to an exterior portion of a patient's body. The position information can be used to provide CPR feedback to a rescuer. In other applications, the position information can be used to provide prompts to a user to change the position of the adjunct.

A defibrillator (AED) and method for using a defibrillator incorporates a user activated button truncates an ongoing ECG analysis to immediately perform a different defibrillator-related function. The AED may use two different ECG analysis algorithms having different sensitivities to a shockable cardiac rhythm, and a press of the button may automatically shift from a first algorithm to a second algorithm with the higher sensitivity. The button may also allow truncation of ongoing analysis and CPR for immediate preparation for electrotherapy.

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.

An electrode for use with a therapeutic current delivery system can include a flexible, water vapor-permeable, conductive adhesive material; a current dispersing element in contact with the conductive adhesive material; and a non-conductive, flexible, water vapor-permeable, electrically-insulating top layer provided in contact with the current dispersing element. The current dispersing element can be conductive at least laterally along a plane of the electrode. The conductive adhesive material can be conductive in a direction substantially orthogonal to the plane of the electrode and semi-conductive in a direction substantially lateral to the plane of the electrode.

A method for treating a patient includes providing a defibrillation and pacing device configured to be worn on a continuous basis by a patient, the defibrillation and pacing device comprising a (i) capacitor and associated circuitry and (ii) an activity sensor. The method includes placing on the patient electrodes configured to detect an ECG of the patient, monitoring the ECG signals and activity of the patient, determining from at least the ECG signal and activity of the patient whether the patient meets an at least one of a bradycardia condition and asystole condition, and, if it is determined that the patient meets the bradycardia condition, providing pacing therapy.