Abstract: An apparatus and method is presented for improving cardiac function after successful termination of a tachyarrhythmia such as ventricular fibrillation. A series of electrical stimulation pulses are delivered prior to a defibrillation shock if one or more specific criteria are met.

Abstract: Systems and methods of verifying that implantable cardiac devices operate as intended in a particular patient involve one or more of determining proper placement of system components, determining stimulus levels useful for individual patient stratification, and determining stimulus levels that indicate efficacy of devices, implantable within a given patient. A pacing stimulus set at a surface pacing level is delivered to a patient's heart using surface electrodes. The patient is determined to not be a candidate for implantation of a subcutaneous defibrillation system if the surface pacing level needed to capture the heart exceeds a predetermined level. The patient may be determined to be a candidate for implantation of a subcutaneous system if the surface pacing level needed to effect capture is within an acceptance level. Such determinations are preferably based on a proportionality relationship between a subcutaneous defibrillation level and a surface pacing level.

Abstract: A cardiac sensing and stimulation system includes a housing within which energy delivery circuitry and detection circuitry are provided. Subcutaneous electrodes are coupled to the energy delivery and detection circuitry and arranged in a non-contacting relationship with respect to cardiac tissue, great vessels, and coronary vasculature. A lead system is coupled to the energy delivery and detection circuitry. The lead system electrodes are configured to contact cardiac tissue, great vessels, or coronary vasculature. A controller, provided in the housing, is coupled to the energy delivery and detection circuitry. The controller configures the system to operate in a first mode using at least the subcutaneous electrodes, and to operate in a second mode using at least the lead electrodes. The controller can selectively switch between the first and second modes, and selectively enable and disable components and circuitry associated with the first and second modes and combinations of these modes.

Abstract: An approach for implementing a subcutaneous medical electrode system involves positioning a number of electrode subsystems in relation to a heart so that a majority of ventricular tissue is included within a volume defined between the electrode subsystems. One of the electrode subsystems so positioned may include a can electrode located on a housing enclosing a medical device. The medical device may be configured to provide therapeutic, diagnostic, or monitoring functions, including, for example, cardiac arrhythmia therapy.

Abstract: An implantable subcutaneous device and method employ a lead and/or electrode for cardiac monitoring and intervention. The device includes an implantable lead having a lead body, a subcutaneous electrode supported by the lead body, and a pharmacological agent provided on the implantable lead body and/or an inactive can portion. The pharmacological agent provides a temporary therapeutic treatment to subcutaneous non-intrathoracic tissue. A method of implanting subcutaneous leads involves providing a lead including a lead body, a subcutaneous electrode, and a pharmacological agent, and delivering the pharmacological agent to subcutaneous non-intrathoracic tissue surrounding the lead.

Abstract: Implantable subcutaneous devices and methods incorporating a lead and/or electrode for cardiac monitoring and intervention, the lead employing chronic fixation elements including, for example, ridges, grooves, surface roughness, porosity, combined with acute fixation elements such as, for example, a suture site. A method of implanting subcutaneous leads may involve providing a lead comprising a lead body, an electrode, an acute fixation element, and one or more chronic fixation elements, and securing one or both of the lead body and the electrode to subcutaneous non-intrathoracic tissue at one or more fixation sites using the fixation elements. The method may involve: introducing a sheath into a subcutaneous non-intrathoracic body location of a patient; providing a lead comprising a lead body and an electrode; advancing the lead through the sheath and to the subcutaneous non-intrathoracic body location; fixing the lead to subcutaneous non-intrathoracic tissue; and removing the sheath from the patient.

Abstract: Subcutaneous leads that incorporate active fixation elements including, for example, helical coils, provide for fixation of cardiac lead components within a patient. An implantable lead includes a lead body with a supported electrode configured for subcutaneous non-intrathoracic placement within a patient. A fixation element is provided on the implantable lead and configured to actively secure one or both of the subcutaneous electrode and the lead body in tissue. A delivery apparatus comprising a sheath may be employed that is configured to introduce the lead to a desired subcutaneous non-intrathoracic location. Lead delivery typically involves introducing a sheath into a subcutaneous non-intrathoracic body location of a patient, providing a lead supporting an electrode, advancing the lead through the sheath, actively fixing the lead to tissue, and thereafter removing the sheath from the patient.

Abstract: An implantable subcutaneous device includes a lead and electrode for cardiac monitoring and intervention. The device has an implantable lead including a lead body, a subcutaneous electrode supported by the lead body and a pharmacological agent impelled from the device using phoresis. The pharmacological agent provides a therapeutic treatment to subcutaneous non-intrathoracic tissue. A method of implanting subcutaneous leads involves providing a lead including a lead body, a subcutaneous electrode, and a pharmacological agent and using phoresis to impel the pharmacological agent into subcutaneous non-intrathoracic tissue surrounding the lead.

Abstract: Subcutaneous systems and leads may be fixed in tissue after placement by use of one or more expanding fixation elements. An expanding fixation element is provided on an implantable lead and configured to secure one or both of a subcutaneous electrode and the lead body within subcutaneous non-intrathoracic tissue. A delivery apparatus comprising a sheath may be included that is configured to introduce the lead to a desired subcutaneous non-intrathoracic location within the patient. A method of lead delivery typically involves introducing a sheath into a subcutaneous non-intrathoracic body location of a patient, providing a lead comprising a lead body and an electrode, and advancing the lead through the sheath and to the subcutaneous non-intrathoracic body location. The method further involves fixing the lead to subcutaneous non-intrathoracic tissue using an expanding fixation element and thereafter removing the sheath from the patient.

Abstract: An implantable subcutaneous device and method employ a lead and an electrode for cardiac monitoring and intervention. The device includes an implantable lead having a lead body, a subcutaneous electrode coupled to the lead body, and a pharmacological agent provided on the implantable lead and/or electrode. The pharmacological agent provides a temporary therapeutic treatment to subcutaneous non-intrathoracic tissue. A method of implanting subcutaneous leads involves providing a lead including a lead body, a subcutaneous electrode, and a pharmacological agent, and delivering the pharmacological agent to subcutaneous non-intrathoracic tissue surrounding the lead.

Abstract: Implantable subcutaneous devices and methods employ a lead and/or electrode for cardiac monitoring and/or intervention. The devices and methods may employ one or more fixation elements including, for example, tines, tines with barbs, spring-loaded tines, flexible or collapsible tines, and other tined fixation mechanisms configured to passively secure one or both of the electrode or body of the lead in subcutaneous non-intrathoracic tissue. A method of implanting subcutaneous leads according to the present invention involves providing a lead comprising a lead body, an electrode, and one or more fixation elements, and passively securing one or both of the lead body and the electrode to subcutaneous non-intrathoracic tissue at one or more fixation sites using the fixation elements. The method may involve use of a delivery device, such as a sheath, for lead delivery to a subcutaneous non-intrathoracic implant site.

Abstract: Methods and devices of cardiac electrode placement involve locating electrodes on a thorax of a patient. Surface pacing levels are determined relative to a pacing limit. Surface electrode locations are selected or rejected based on the level being within a limit. Electrodes may be relocated to new locations, and new surface pacing levels determined, until a new surface pacing level falls within the pacing limit. Selecting or rejecting electrode locations involves selecting locations suitable for implantation of subcutaneous cardiac electrodes and implanting at the selected locations.

Abstract: Systems and methods of verifying that implantable cardiac devices operate as intended in a particular patient involve one or more of determining proper placement of system components, determining stimulus levels useful for individual patient stratification, and determining stimulus levels that indicate efficacy of devices, implantable within a given patient. A pacing stimulus set at a surface pacing level is delivered to a patient's heart using surface electrodes. The patient is determined to not be a candidate for implantation of a subcutaneous defibrillation system if the surface pacing level needed to capture the heart exceeds a predetermined level. The patient may be determined to be a candidate for implantation of a subcutaneous system if the surface pacing level needed to effect capture is within an acceptance level. Such determinations are preferably based on a proportionality relationship between a subcutaneous defibrillation level and a surface pacing level.

Abstract: Systems and methods provide for sensing of cardiac activity from a subcutaneous, non-intrathoracic location, and detecting a cardiac condition necessitating treatment in response to the sensed cardiac activity. One of a number of cardiac therapies may be selectively delivered to treat the detected cardiac condition, such cardiac therapies including at least a tachycardia therapy, a bradycardia therapy, and an asystole prevention therapy.

Abstract: A reconfigurable cardiac device includes a housing, and detection circuitry and energy delivery circuitry provided in the housing. One or more subcutaneous, non-intrathoracic electrodes are coupled to the energy delivery and detection circuitry. A lead interface is provided on the housing and coupled to the energy delivery and detection circuitry. The lead interface is configured to receive at least one lead that includes one or more intrathoracic lead electrodes. A controller is provided in the housing and coupled to the lead interface and the energy delivery and detection circuitry. The system is operable in a first configuration using the subcutaneous electrodes in the absence of the lead and operable in a second configuration using at least one or more of the lead electrodes. The system is capable of providing cardiac activity sensing and stimulation in each of the first and second system configurations, respectively.

Abstract: Tissue dissection instruments and methods provide for fluid delivery and aspiration during subcutaneous dissection. A dissection tool includes a handle and a dissecting member. The dissecting member extends from the distal end of the handle, and a fluid channel system extends from at least the proximal end to the distal end of the dissecting member. The fluid channel system terminates in a port system. The port system may include one or more apertures, one or more channels, and be adapted to provide fluid transport and/or aspiration, such fluids including irrigation fluids, fluids having analgesics, antibiotics, hemostatic agents, healing accelerating agents, agents that improve the electrical properties of tissue, and combinations of fluids and agents. The dissection tool may be straight or curved, rigid or malleable, and shaped to provide dissection paths suitable for the implantation of subcutaneous electrodes.

Abstract: Transthoracic cardiac stimulation therapies provide for detection and treatment of cardiac asystole subsequent to delivery of a defibrillation therapy. A pacing therapy is transthoracicly delivered to terminate detected cardiac asystole using residual energy from a defibrillation energy storage source. The residual energy usable for the pacing therapy is sufficient to transthoracicly deliver at least one pacing pulse, and is typically sufficient to deliver a series of pacing pulses, prior to depletion of the defibrillation energy storage source. Detection of cardiac asystole is performed following delivery of each pacing pulse, and subcutaneous pacing support is terminated in response to detecting cardiac asystole termination.

Abstract: A method and apparatus for assessing the risk of atrial fibrillation in a patient by calculating the relative frequency of short and long intervals between successive heart beats during sinus rhythm is presented. An imbalance of short over long sinus intervals has been found to indicate a higher risk of atrial fibrillation. An implantable cardiac device may be configured to automatically deliver interventional therapy to restore sinus interval balance when such an imbalance is detected.

Abstract: An apparatus and method is presented for improving cardiac function after successful termination of a tachyarrhythmia such as ventricular fibrillation. A series of electrical stimulation pulses are delivered prior to a defibrillation shock if one or more specific criteria are met.

Abstract: Certain cardiac arrhythmias can be prevented by appropriate electrical stimulation of autonomic nerves innervating the heart. An implantable cardiac rhythm management device is configured to deliver such stimulation when an autonomic imbalance is predicted to be present via an endovascular electrode. Autonomic imbalance may be predicted to be present based upon circadian rhythms, detected heart rates, or detected heart rate variability.