A patient-worn ambulatory cardiac monitoring device for monitoring a patient during a patient activity includes at least one physiological sensor configured to detect signals indicative of cardiac activity, an activity sensor and associated circuitry configured to monitor patient movements, and a vibrational sensor configured to monitor a cardio-vibrational signal of the patient. The at least one physiological sensor can include one of an ECG sensor and a heart rate sensor. At least one processor in communication with the at least one physiological sensor, the activity sensor, and the vibrational sensor, is configured to measure, during the patient activity, at least one time interval between an ECG fiducial point in an ECG signal and a cardio-vibrational fiducial point in the cardio-vibrational signal during a cardiac cycle of the patient's heart.

In embodiments, a wearable cardioverter defibrillator (WCD) system includes a support structure for wearing by an ambulatory patient. When worn, the support structure maintains electrodes on the patient's body. Different pairs of these electrodes define different channels, and different patient ECG signals can be sensed from the channels. The ECG signals can be analyzed to determine which one is the best to use, for the WCD system to make a shock/no shock decision. The analysis can be according to widths of the QRS complexes, consistency of the QRS complexes, or heart rate agreement statistics.

An ambulatory medical device comprising: a monitoring component comprising at least one sensing electrode for detecting a cardiac condition of a patient; at least one processor configured for: adjusting one or more detection parameters for detecting the cardiac condition of the patient based at least in part on at least one of 1) one or more environmental conditions and 2) input received from the monitoring component; and providing at least one of an alarm and a treatment in response to detecting the cardiac condition of the patient based on the adjusted one or more detection parameters.

Automated CPR systems incorporating biological feedback can include an automated compression piston system, a data acquisition system, computer systems for running various control algorithms, ventilation control systems, and/or drug delivery systems. Automated CPR systems can be used as stand-alone systems for treating patients in cardiac arrest, or they can be used to administer pretreatment to a patient prior to defibrillation.

A medical device, such as an extra-cardiovascular implantable cardioverter defibrillator (ICD), senses R-waves from a first cardiac electrical signal by a first sensing channel and stores a time segment of a second cardiac electrical signal acquired by a second sensing channel in response to each sensed R-wave. The ICD determines morphology match scores from the stored time segments of the second cardiac electrical signal and, based on the morphology match scores, withholds detection of a tachyarrhythmia episode. In some examples, the ICD detects T-wave oversensing based on the morphology match scores and withholds detection of a tachyarrhythmia episode in response to detecting the T-wave oversensing.

In some embodiments, a wearable medical device system includes a processor configured to determine whether a patient requires electrical therapy to be provided via a plurality of therapy electrodes, the electrical therapy comprising discharging at least a portion of a stored electrical charge from an energy storage module, and if so, cause a fluid deploying mechanism to deploy a portion of the stored fluid to an interface between at least two therapy electrodes and the patient's skin prior to providing the electrical therapy, the deployed portion of fluid adapted to decrease the impedance measured by an impedance measurement circuit, and cause the fluid deploying mechanism to deploy an additional portion of fluid in response to the impedance measured by the impedance measurement circuit increasing above a threshold during the electrical therapy.

A medical device is configured to deliver anti-tachycardia pacing (ATP) in the presence of T-wave alternans. The device is configured to detect a ventricular tachyarrhythmia from a cardiac electrical signal received by the medical device. In response to the detected ventricular tachyarrhythmia, the device delivers a plurality of ATP pulses at alternating time intervals. The alternating time intervals comprise at least a first ATP time interval separating a first pair of the ATP pulses and a second ATP time interval different than the first ATP time interval. The second ATP time interval consecutively follows the first ATP time interval and separates a second pair of the ATP pulses.

A compact integrated patch may be used to collect physiological data. The patch may be wireless. The patch may be utilized in everyday life as well as in clinical environments. Data acquired by the patch and/or external devices may be interpreted and/or be utilized by healthcare professionals and/or computer algorithms (e.g., third party applications). Data acquired by the patch may be interpreted and be presented for viewing to healthcare professionals and/or ordinary users.

An extra-cardiovascular implantable cardioverter defibrillator (ICD) having a high voltage therapy module is configured to control a high voltage charging circuit to charge a capacitor to a pacing voltage amplitude to deliver charge balanced pacing pulses. The capacitor is chargeable to a shock voltage amplitude that is greater than the pacing voltage amplitude. The ICD is configured to enable switching circuitry of the high voltage therapy module to discharge the capacitor to deliver a first pulse having a first polarity and a leading voltage amplitude corresponding to the pacing voltage amplitude for pacing the patient's heart via a pacing electrode vector selected from extra-cardiovascular electrodes. The high voltage therapy module delivers a second pulse after the first pulse. The second pulse has a second polarity opposite the first polarity and balances the electrical charge delivered during the first pulse.

A wearable medical device is provided. The device includes electrodes to receive electrical signals from a patient, monitor for a cardiac arrhythmia, and provide a therapeutic shock to the patient in response to detecting the arrhythmia. The device includes a user interface to receive patient input indicating initiation or termination of a high-noise activity. The device can include accelerometers to generate motion signals. The device includes a processor to monitor for initiation or termination of the high-noise activity based on a noise level in the electrical signals, the motion signals, and the patient input. The processor can cause, in response to the initiation of the high-noise activity, an arrhythmia detection process to execute in an activity-induced noise (AIN) robust mode, and cause, in response to the termination of the high-noise activity, the arrhythmia detection process to execute in an AIN sensitive mode.