Abstract: A medical device is configured to deliver a cardiac pacing pulse having a pacing pulse amplitude for delivery to an electrode terminal of the medical device. The medical device is configured to pull a latching current by an internal adjustable load of the medical device coupled to a low side of a high side switch of a high voltage output circuit of the medical device to hold the high side switch in a conducting state during a first portion of the cardiac pacing pulse in some examples. The medical device may be configured to pull a holding current to hold the high side switch in a conducting state during a second portion of the cardiac pacing pulse. The holding current may be less than the latching current.

Abstract: A medical device is configured to perform a first analysis of ventricular event signals during a long pause detection interval for detecting a suspected long pause in ventricular activity and perform a second analysis of ventricular event signals for detecting suspected tachyarrhythmia undersensing. The medical device may perform a morphology analysis of a cardiac signal segment in response to detecting at least one of a suspected long pause based on the first analysis or suspected tachyarrhythmia undersensing based on the second analysis.

Abstract: A medical device is configured to determine an amplitude metric from a cardiac signal segment sensed over a predetermined time interval and determine if the amplitude metric meets an amplitude threshold. The medical device is configured to perform a first analysis of the cardiac electrical signal segment for detecting a first arrhythmia when the amplitude metric does not meet the amplitude threshold and perform a second analysis of the cardiac electrical signal segment for detecting a second arrhythmia different than the first arrhythmia in response to the amplitude metric meeting the amplitude threshold.

Abstract: A medical device is configured to determine tachyarrhythmia evidence in a cardiac signal segment received from a cardiac electrical signal sensed during a pacing escape interval started to schedule a pending cardiac pacing pulse. The medical device may delay the pending cardiac pacing pulse in response to determining the tachyarrhythmia evidence during the pacing escape interval.

Abstract: A system, method and leak signal discriminator for detection of a leak or mechanical breach in a catheter shaft in the presence of an electrical interferer are disclosed. According to one aspect, a leak signal discriminator having a leak detection circuit is configured to distinguish between a leak signal arising from a leak in a catheter and an interfering signal arising from an electrical interferer. The leak signal discriminator includes circuitry configured to receive from the leak detection circuit a response signal responsive to a test signal the test signal having component signals, each component signal being at a different frequency, and distinguish between a leak and an electrical interferer based at least in part on an evaluation of the response signal.

Abstract: A medical device is configured to sense first ventricular event signals from a first cardiac electrical signal and sense second ventricular event signals from a second cardiac electrical signal. The medical device is configured to determine sensed event data in response to the first ventricular event signals and the second ventricular event signals. The medical device may select one of the first cardiac electrical signal or the second cardiac electrical signal for providing input for tachyarrhythmia detection based on the sensed event data.

Abstract: A medical device is configured to receive cardiac electrical signals and sense ventricular event signals from the cardiac electrical signals. The medical device may start a validation window in response to sensing a ventricular event signal and determine if the ventricular event signal is a valid event signal or an invalid event signal based on processing of a different cardiac electrical signal than the cardiac electrical signal from which the ventricular event signal was sensed.

Abstract: A medical device is configured to determine tachyarrhythmia evidence in a cardiac signal segment received from a cardiac electrical signal sensed during a pacing escape interval started to schedule a pending cardiac pacing pulse. The medical device may delay the pending cardiac pacing pulse in response to determining the tachyarrhythmia evidence during the pacing escape interval.

Abstract: A medical device is configured to sense first ventricular event signals from a first cardiac electrical signal and sense second ventricular event signals from a second cardiac electrical signal. The medical device is configured to determine sensed event data in response to the first ventricular event signals and the second ventricular event signals. The medical device may select one of the first cardiac electrical signal or the second cardiac electrical signal for providing input for tachyarrhythmia detection based on the sensed event data.

Abstract: A medical device is configured to receive cardiac electrical signals and sense ventricular event signals from the cardiac electrical signals. The medical device may start a validation window in response to sensing a ventricular event signal and determine if the ventricular event signal is a valid event signal or an invalid event signal based on processing of a different cardiac electrical signal than the cardiac electrical signal from which the ventricular event signal was sensed.

Abstract: A method and system for feedback control for cryo-mapping and cryoablation are disclosed. According to one aspect, a cryo-mapping and cryoablation control system includes a first control device configured to receive a target parameter value and a measured output parameter and to output an injection pressure target signal based on a first difference between the target parameter value and the measured output parameter. The system also includes a second control device configured to receive the injection pressure target signal and to output a valve control signal, the valve control signal being used to set a position of an injection pressure valve. The first control device is configured to determine a value of the injection pressure target signal to drive the first difference toward zero.

Abstract: Systems and methods for cryoablation. One example system includes an interior portion, an exterior portion and a treatment element. The system includes a first loop in the interior portion of the system, the first loop having a first controller, at least one valve, and a first sensor; a second loop in the interior portion of the system, the second loop having a second controller, and at least one valve, and a second sensor; a pressurized coolant supply in fluid communication with the first loop and the second loop; and a temperature sensor disposed on the exterior portion of the system, the temperature sensor being configured to monitor the temperature on the exterior portion of the system.

Abstract: An implantable medical device system capable of sensing cardiac electrical signals includes a sensing circuit, a therapy delivery circuit and a control circuit. The sensing circuit is configured to receive a cardiac electrical signal and sense a cardiac event in response to the signal crossing a cardiac event sensing threshold. The therapy delivery circuit is configured to deliver an electrical stimulation therapy to a patient's heart via the electrodes coupled to the implantable medical device. The control circuit is configured to control the sensing circuit to set a starting value of the cardiac event sensing threshold and hold the starting value constant for a sense delay interval. The control circuit is further configured to detect an arrhythmia based on cardiac events sensed by the sensing circuit and control the therapy delivery circuit to deliver the electrical stimulation therapy in response to detecting the arrhythmia.

Abstract: A medical device comprises a sensing circuit configured to sense at least one cardiac electrical signal, sense first ventricular event signals from the at least one cardiac electrical signal according to a sensitivity setting set to a first amplitude; and a control circuit in communication with the sensing circuit, the control circuit configured to determine that the at least one cardiac electrical signal meets suspected undersensing criteria, in response to determining that the suspected undersensing criteria are met, perform a morphology analysis of a first cardiac signal segment acquired from a first cardiac electrical signal of the at least one cardiac electrical signal sensed by the sensing circuit over a first predetermined time interval, determine that the first cardiac signal segment is a first tachyarrhythmia segment based on the morphology analysis, and adjust the sensitivity setting from the first amplitude to a second amplitude less than the first amplitude in response to determining that the firs

Abstract: An implantable medical device system is configured to sense cardiac events in response to a cardiac electrical signal crossing a cardiac event sensing threshold. A control circuit is configured to determine a drop time interval based on a heart rate and control a sensing circuit to hold the cardiac event sensing threshold at a threshold value during the drop time interval.

Abstract: 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.

Abstract: A system, method and leak signal discriminator for detection of a leak or mechanical breach in a catheter shaft in the presence of an electrical interferer are disclosed. According to one aspect, a leak signal discriminator having a leak detection circuit is configured to distinguish between a leak signal arising from a leak in a catheter and an interfering signal arising from an electrical interferer. The leak signal discriminator includes circuitry configured to receive from the leak detection circuit a response signal responsive to a test signal the test signal having component signals, each component signal being at a different frequency, and distinguish between a leak and an electrical interferer based at least in part on an evaluation of the response signal.

Abstract: A system, method and leak signal discriminator for detection of a leak or mechanical breach in a catheter shaft in the presence of an electrical interferer are disclosed. According to one aspect, a leak signal discriminator having a leak detection circuit is configured to distinguish between a leak signal arising from a leak in a catheter and an interfering signal arising from an electrical interferer. The leak signal discriminator includes circuitry configured to receive from the leak detection circuit a response signal responsive to a test signal the test signal having component signals, each component signal being at a different frequency, and distinguish between a leak and an electrical interferer based at least in part on an evaluation of the response signal.

Abstract: 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.

Abstract: A medical electrical lead includes a lead body, a high voltage electrode positioned on the lead body, the high voltage electrode comprising a proximal coated portion, a distal coated portion, and an uncoated portion. Additionally, the medical electrical lead includes a first low voltage electrode and a second low voltage electrode distal to the first low voltage electrode, wherein a first line passes through the first low voltage electrode and the second low voltage electrode, wherein a second line passes through the first low voltage electrode and the uncoated portion, the second line forming a first angle with the first line, and wherein a third line passes through the second low voltage electrode and the uncoated portion, the third line forming a second angle with the first line.