Abstract: An implantable cardiac defibrillator (ICD) system includes an ICD implanted subcutaneously in a patient, a defibrillation lead having a proximal portion coupled to the ICD and a distal portion having a defibrillation electrode configured to deliver a defibrillation or cardioversion shock to a heart of the patient, and a pacing lead that includes a distal portion having one or more electrodes and a proximal portion coupled to the ICD. The distal portion of the pacing lead is implanted at least partially along a posterior side of a sternum of the patient within the anterior mediastinum. The ICD is configured to provide pacing pulses to the heart of the patient via the pacing lead and provide defibrillation shocks to the patient via the defibrillation lead. As such, the implantable cardiac system provides pacing from the substernal space for an extravascular ICD system.

Abstract: An implantable cardiac defibrillator (ICD) system includes an ICD implanted subcutaneously in a patient, a defibrillation lead having a proximal portion coupled to the ICD and a distal portion having a defibrillation electrode configured to deliver a defibrillation or cardioversion shock to a heart of the patient, and a pacing lead that includes a distal portion having one or more electrodes and a proximal portion coupled to the ICD. The distal portion of the pacing lead is implanted at least partially along a posterior side of a sternum of the patient within the anterior mediastinum. The ICD is configured to provide pacing pulses to the heart of the patient via the pacing lead and provide defibrillation shocks to the patient via the defibrillation lead. As such, the implantable cardiac system provides pacing from the substernal space for an extravascular ICD system.

Abstract: Devices and implantation methods utilizing subcutaneous placement into a patient are disclosed for the insertion, advancement and positioning of a subcutaneous implantable medical device (SIMD) such as a medical electrical lead. The device for implanting the SIMD is configured having a pre-biased distal curve for creating a pathway to an implant location within a substernal space.

Abstract: A system and method of implanting pacing lead in a patient's heart. The system may include a catheter configured to by inserted through the coronary sinus ostium such that the distal end region of the catheter is positioned past the anterolateral vein and proximate at least one septal perforating vein. The catheter is configured to inject contrast proximate the septal perforating vein to identify an implant region for a pacing lead. Further, a controller is configured to deliver pacing therapy to the implant region.

Abstract: Implantable medical electrical leads having electrodes arranged such that a defibrillation coil electrode and a pace/sense electrode(s) are concurrently positioned substantially over the ventricle when implanted as described. The leads include an elongated lead body having a distal portion and a proximal end, a connector at the proximal end of the lead body, a defibrillation electrode located along the distal portion of the lead body, wherein the defibrillation electrode includes a first electrode segment and a second electrode segment proximal to the first electrode segment by a distance. The leads may include at least one pace/sense electrode, which in some instances, is located between the first defibrillation electrode segment and the second defibrillation electrode segment.

Abstract: An extra-cardiovascular medical device is configured to select a capacitor configuration from a capacitor array and deliver a low voltage, pacing pulse by discharging the selected capacitor configuration across an extra-cardiovascular pacing electrode vector. In some examples, the medical device is configured to determine the capacitor configuration based on a measured impedance of the extra-cardiovascular pacing electrode vector.

Abstract: A medical device is configured to deliver therapeutic electrical stimulation pulses by generating frequency modulated electrical stimulation pulse signals. The medical device includes a pulse signal source and a modulator. The pulse signal source generates an electrical stimulation pulse signal having a pulse width. The modulator may include a high frequency modulator configured to modulate a frequency of the pulse signal from a starting frequency down to a minimum frequency during the pulse width. The modulator may include a low frequency bias generator to modulate the offset of the pulse signal between a minimum offset and a maximum offset in other examples.

Abstract: A medical device is configured to deliver therapeutic electrical stimulation pulses by generating frequency modulated electrical stimulation pulse signals. The medical device includes a pulse signal source and a modulator. The pulse signal source generates an electrical stimulation pulse signal having a pulse width. The modulator may include a high frequency modulator configured to modulate a frequency of the pulse signal from a starting frequency down to a minimum frequency during the pulse width. The modulator may include a low frequency bias generator to modulate the offset of the pulse signal between a minimum offset and a maximum offset in other examples.

Abstract: An extra-cardiovascular medical device is configured to select a capacitor configuration from a capacitor array and deliver a low voltage, pacing pulse by discharging the selected capacitor configuration across an extra-cardiovascular pacing electrode vector. In some examples, the medical device is configured to determine the capacitor configuration based on a measured impedance of the extra-cardiovascular pacing electrode vector.

Abstract: Implantable medical electrical leads having electrodes arranged such that a defibrillation coil electrode and a pace/sense electrode(s) are concurrently positioned substantially over the ventricle when implanted as described. The leads include an elongated lead body having a distal portion and a proximal end, a connector at the proximal end of the lead body, a defibrillation electrode located along the distal portion of the lead body, wherein the defibrillation electrode includes a first electrode segment and a second electrode segment proximal to the first electrode segment by a distance. The leads may include at least one pace/sense electrode, which in some instances, is located between the first defibrillation electrode segment and the second defibrillation electrode segment.

Abstract: An intracardiac ventricular pacemaker includes a pulse generator for delivering ventricular pacing pulses, an impedance sensing circuit, and a control circuit in communication with the pulse generator and the impedance sensing circuit. The pacemaker is configured to produce an intraventricular impedance signal, detect an atrial systolic event using the intraventricular impedance signal, set an atrioventricular pacing interval in response to detecting the atrial systolic event, and deliver a ventricular pacing pulse in response to the atrioventricular pacing interval expiring.

Abstract: Implantable leadless cardiac pacing systems and methods for providing substernal pacing using the leadless cardiac pacing systems are described. In one embodiment, an implantable leadless cardiac pacing system includes a housing, a first electrode on the housing, a second electrode on the housing, and a pulse generator within the housing and electrically coupled to the first electrode and the second electrode. The housing is implanted substantially within an anterior mediastinum of a patient and the pulse generator is configured to deliver pacing pulses to a heart of the patient via a therapy vector formed between the first and second electrodes.

Abstract: Anchoring mechanisms for an implantable electrical medical lead that is positioned within a substernal space are disclosed. The anchoring mechanisms fixedly-position a distal portion of the lead, that is implanted in the substernal space.

Abstract: Implantable medical electrical leads having electrodes arranged such that a defibrillation coil electrode and a pace/sense electrode(s) are concurrently positioned substantially over the ventricle when implanted as described. The leads include an elongated lead body having a distal portion and a proximal end, a connector at the proximal end of the lead body, a defibrillation electrode located along the distal portion of the lead body, wherein the defibrillation electrode includes a first electrode segment and a second electrode segment proximal to the first electrode segment by a distance. The leads may include at least one pace/sense electrode, which in some instances, is located between the first defibrillation electrode segment and the second defibrillation electrode segment.

Abstract: Implantable leadless cardiac pacing systems and methods for providing substernal pacing using the leadless cardiac pacing systems are described. In one embodiment, an implantable leadless cardiac pacing system includes a housing, a first electrode on the housing, a second electrode on the housing, and a pulse generator within the housing and electrically coupled to the first electrode and the second electrode. The housing is implanted substantially within an anterior mediastinum of a patient and the pulse generator is configured to deliver pacing pulses to a heart of the patient via a therapy vector formed between the first and second electrodes.

Abstract: In some examples, a medical device system includes an electrode. The medical device system may include impedance measurement circuitry coupled to the electrode, the impedance measurement circuitry may be configured to generate an impedance signal indicating impedance proximate to the electrode. The medical device system may include processing circuitry that may be configured to identify a first component of the impedance signal. The first component of the impedance signal may be correlated to a cardiac event. The processing circuitry may be configured to determine that the cardiac event occurred based on the identification of the first component of the impedance signal.

Abstract: An intracardiac ventricular pacemaker includes a pulse generator for delivering ventricular pacing pulses, an impedance sensing circuit, and a control circuit in communication with the pulse generator and the impedance sensing circuit. The pacemaker is configured to produce an intraventricular impedance signal, detect an atrial systolic event using the intraventricular impedance signal, set an atrioventricular pacing interval in response to detecting the atrial systolic event, and deliver a ventricular pacing pulse in response to the atrioventricular pacing interval expiring.

Abstract: Anchoring mechanisms for an implantable electrical medical lead that is positioned within a substernal space are disclosed. The anchoring mechanisms fixedly-position a distal portion of the lead, that is implanted in the substernal space.

Abstract: Implantable cardiac pacing systems and methods for providing substernal pacing are described. In one example, a cardiac pacing system includes a pacemaker implanted in a patient and an implantable medical electrical lead. The implantable medical electrical lead includes an elongated lead body having a proximal end and a distal portion, a connector configured to couple to the pacemaker at the proximal end of the elongated lead body, and one or more electrodes along the distal portion of the elongated lead body, wherein the distal portion of the elongated lead body of the lead is implanted substantially within an anterior mediastinum of the patient and the pacemaker is configured to deliver pacing pulses to a heart of the patient.

Abstract: Substernal implantable cardioveter-defibrillator (ICD) systems and methods for providing substernal electrical stimulation therapy to treat malignant tachyarrhythmia, e.g., ventricular tachycardia (VT) and ventricular fibrillation (VF) are described. In one example, an implantable cardioveter-defibrillator (ICD) system includes an ICD implanted in a patient and an implantable medical electrical lead. The lead includes an elongated lead body having a proximal end and a distal portion, a connector at the proximal end of the lead body configured to couple to the ICD, and one or more electrodes along the distal portion of the elongated lead body. The distal portion of the elongated lead body of the lead is implanted substantially within an anterior mediastinum of the patient and the ICD is configured to deliver electrical stimulation to a heart of the patient using the one or more electrodes.