Subcutaneous implantable string shaped defibrillator for providing cardiac resynchronization therapy (CRT), including a flexible elongated body, at least two defibrillation leads, at least one sensor, at least two transition units and at least one epicardial lead, the defibrillation leads for providing at least one cardioversion defibrillation shock, the sensor being positioned on at least one of the defibrillation leads, for determining at least one metric of a heart, the transition units for respectively coupling the defibrillation leads to opposite ends of the elongated body, and the epicardial lead, coupled with the elongated body via at least one of the transition units, for providing at least one CRT pulse, the elongated body including a plurality of linked units, the linked units encapsulating at least one capacitor, at least one power source and a processor, wherein the processor provides at least one signal to the epicardial lead for providing the CRT pulse.

An object of the present invention is to provide a new electric device for defibrillation and a method for generating a defibrillation signal. The electric device for defibrillation includes an electrocardiogram waveform input unit; and an enable signal generating unit, wherein the electric device for defibrillation is configured to generate an enable signal from the enable signal generating unit after a peak of an event is surpassed and when or after condition 1 is satisfied, the event being estimated to be an R-wave of an electrocardiogram waveform, the electrocardiogram waveform being obtained from a human body and inputted from the electrocardiogram waveform input unit, and the condition 1 is that a differential value in a differentiated waveform generated based on the electrocardiogram waveform, which corresponds to the event estimated to be the R-wave, is a negative constant C.sub.3 value or less.

A computer implemented method and system are provided for detecting premature ventricular contractions (PVCs) in cardiac activity. The method and system obtain cardiac activity (CA) signals for a series of beats, and, for at least a portion of the series of beats, calculate QRS scores for corresponding QRS complex segments from the CA signals. The method and system calculate a variability metric for QRS scores across the series of beats, calculate a QRS complex template using QRS segments from the series of beats, calculate correlation coefficients between the QRS complex template and the QRS complex segments, compare the variability metric to a variability threshold and the correlation coefficients to a correlation threshold, and designate the CA signals to include a predetermined level of PVC burden based on the determining.

A subcutaneous cardiac defibrillation system implantable comprising a housing and a subcutaneous implantable lead comprising a proximal end connected to the housing and a distal free end. The subcutaneous implantable lead comprises at least one defibrillation electrode and at least three detection electrodes. The first detection electrode and the second detection electrode form a first dipole, and the third detection electrode and the first detection electrode, or the third detection electrode and the second detection electrode, or the housing and one of said detection electrodes, form a second dipole. The defibrillation electrode is positioned between the second detection electrode and the third detection electrode, the first dipole is positioned between the housing and the defibrillation electrode, the third electrode is positioned between the free distal end of the lead and the defibrillation electrode, and the length of the first dipole is shorter than the length of the second dipole.

Methods, apparatus, and systems relating to a Wearable Cardioverter Defibrillator (WCD) system capable of logging event data and/or broadcasting state changes and/or system status information to external clients are described. In an embodiment, a processor stores data corresponding to one or more event markers in memory in response to occurrence of an event. Occurrence of the event is detected based at least in part on detection of one or more parameters by one or more sensors or a signal to be generated by one or more of electrodes of the WCD system. A communication device transmits at least a portion of the stored data to a remote device. A patient condition or a WCD system condition can then be detected based at least in part on analysis of the stored data and/or the transmitted portion of the stored data.

An ambulatory medical device configured to analyze heart rates in different operating modes includes a plurality of ECG sensing electrodes, a plurality of therapy electrodes and at least one processor configured to in a default operating mode, perform a default heart rate calculation for determining a heart rate of the patient for use in detecting a cardiac arrhythmia condition of the patient. The at least one processor is configured to change a device operating mode from a default mode based on detecting patient activity to an activity operating mode, and in the activity operating mode, perform a different heart rate calculation from the default heart rate calculation for determining the heart rate for use in detecting the cardiac arrhythmia condition of the patient during the activity operating mode. The at least one processor is configured to deliver the treatment in response to detecting the cardiac arrhythmia condition.

An extra-cardiovascular implantable cardioverter defibrillator (ICD) having a low voltage therapy module and a high voltage therapy module is configured to select, by a control module of the ICD, a pacing output configuration from at least a low-voltage pacing output configuration of the low voltage therapy module and a high-voltage pacing output configuration of the high voltage therapy module. The high voltage therapy module includes a high voltage capacitor having a first capacitance and the low voltage therapy module includes a plurality of low voltage capacitors each having up to a second capacitance that is less than the first capacitance. The ICD control module controls a respective one of the low voltage therapy module or the high voltage therapy module to deliver extra-cardiovascular pacing pulses in the selected pacing output configuration via extra-cardiovascular electrodes coupled to the ICD.

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.

Some embodiments relate to a method of testing a lead condition in an implanted cardiac device comprising a first defibrillation lead and a second non-defibrillation lead, the method comprising: measuring impedance between the first defibrillation lead and the second non-defibrillation lead by applying a test pulse; and determining a condition of at least one of the defibrillation lead and the non-defibrillation lead according to the measured impedance value.

A method includes, based on respective signals acquired by a plurality of electrodes on an anatomical surface of a heart, computing respective local activation times (LATs) at respective locations of the electrodes. The method further includes, based on the LATs, computing respective directions of electrical propagation at the locations. The method further includes selecting pairs of adjacent ones of the electrodes such that, for each of the pairs, a vector joining the pair is aligned, to within a predefined threshold degree of alignment, with the direction of electrical propagation at the location of one of the electrodes belonging to the pair. The method further includes associating respective bipolar voltages measured by the pairs of electrodes with a digital model of the anatomical surface. Other examples are also described.