Electrical crosstalk between two implantable medical devices or two different therapy modules of a common implantable medical device may be evaluated, and, in some examples, mitigated. In some examples, one of the implantable medical devices or therapy modules delivers electrical stimulation to a nonmyocardial tissue site or a nonvascular cardiac tissue site, and the other implantable medical device or therapy module delivers cardiac rhythm management therapy to a heart of the patient.

Implantable cardiac systems and methods for providing substernal pacing in an ICD system are described. In one example, an implantable cardiac system comprises an ICD system and an implantable leadless pacing device (LPD) communicatively coupled to the ICD system. The ICD system includes an ICD and an implantable defibrillation lead having a proximal portion coupled to the ICD and a distal portion having a defibrillation electrode configured to deliver a defibrillation shock to a heart of the patient. The LPD 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 of the LPD is implanted substantially within an anterior mediastinum of the patient and the pulse generator is configured to deliver pacing pulses to a heart via the first and second electrodes.

In some examples, an electromechanical disassociation state (EMD) of a heart of a patient can be treated by delivering electrical stimulation to a tissue site to at least one of modulate afferent nerve activity or inhibit efferent nerve activity upon determining that the heart is in an electromechanical dissociation state, where the tissue site comprises at least one of a nonmyocardial tissue site or a nonvascular cardiac tissue site. The delivery of electrical stimulation may effectively treat the EMD state of the heart, e.g., by enabling effective mechanical contraction of the heart. In another example, an electromechanical disassociation state of a heart of a patient can be treated by determining autonomic nervous system activity associated with a detected EMD state of the heart of a patient, and delivering electrical stimulation therapy to the patient based on the determined autonomic nervous system activity of the patient associated with the EMD state.

This document describes methods and materials for reducing incision sizes for improving the treatment of pathological conditions, including arrhythmias and trauma, using temperature modulation via implantable devices. For example, this document describes methods and devices for treating atrial and/or ventricular fibrillation by cooling the epicardium.

Implantable cardiac systems and methods for providing substernal pacing in an ICD system are described. In one example, an implantable cardiac system comprises an ICD system and an implantable leadless pacing device (LPD) communicatively coupled to the ICD system. The ICD system includes an ICD and an implantable defibrillation lead having a proximal portion coupled to the ICD and a distal portion having a defibrillation electrode configured to deliver a defibrillation shock to a heart of the patient. The LPD 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 of the LPD is implanted substantially within an anterior mediastinum of the patient and the pulse generator is configured to deliver pacing pulses to a heart via the first and second electrodes.

This document describes methods and materials for reducing incision sizes for improving the treatment of pathological conditions, including arrhythmias and trauma, using temperature modulation via implantable devices. For example, this document describes methods and devices for treating atrial and/or ventricular fibrillation by cooling the epicardium.

In some examples, a medical device includes an elongated structure configured to extend from an access point of a patient through an intercostal space within the patient. The medical device may further include a plurality of electrodes comprising a first subset of electrodes and a second subset of electrodes, where at least the first subset of electrodes is carried on a distal portion of the elongated structure. The first subset of electrodes of the plurality of electrodes may be configured to deliver electrical therapy to a heart of the patient or sense cardiac activity. The second subset of electrodes of the plurality of electrodes may be configured to deliver energy to tissue proximate a ribcage of the patient to reduce a sensation in one or more intercostal nerves.

Implantable cardiac systems and methods for providing substernal pacing in an ICD system are described. In one example, an implantable cardiac system comprises an ICD system and an implantable leadless pacing device (LPD) communicatively coupled to the ICD system. The ICD system includes an ICD and an implantable defibrillation lead having a proximal portion coupled to the ICD and a distal portion having a defibrillation electrode configured to deliver a defibrillation shock to a heart of the patient. The LPD 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 of the LPD is implanted substantially within an anterior mediastinum of the patient and the pulse generator is configured to deliver pacing pulses to a heart via the first and second electrodes.

Electrical crosstalk between two implantable medical devices or two different therapy modules of a common implantable medical device may be evaluated, and, in some examples, mitigated. In some examples, one of the implantable medical devices or therapy modules delivers electrical stimulation to a nonmyocardial tissue site or a nonvascular cardiac tissue site, and the other implantable medical device or therapy module delivers cardiac rhythm management therapy to a heart of the patient.