Source: https://patents.google.com/patent/US20050115561A1/en
Timestamp: 2019-04-24 01:05:01
Document Index: 620169923

Matched Legal Cases: ['§119', 'art 490', 'art 490', 'art 490', 'art 490', 'art 490', 'art 540', 'art 540', 'art 540', 'art 540', 'art 540', 'art 540', 'art 540', 'art 540', 'art 540', 'art 540', 'art 540', 'art 560', 'art 560', 'art 560', 'art 560', 'art 560', 'art 560', 'art 560', 'art 560', 'art 560', 'art 560', 'art 560']

US20050115561A1 - Patient monitoring, diagnosis, and/or therapy systems and methods - Google Patents
Patient monitoring, diagnosis, and/or therapy systems and methods Download PDF
US20050115561A1
US20050115561A1 US10/943,721 US94372104A US2005115561A1 US 20050115561 A1 US20050115561 A1 US 20050115561A1 US 94372104 A US94372104 A US 94372104A US 2005115561 A1 US2005115561 A1 US 2005115561A1
US10/943,721
US7787946B2 (en
2003-08-18 Priority to US10/642,998 priority Critical patent/US8002553B2/en
2003-08-18 Priority to US10/643,006 priority patent/US8192376B2/en
2003-08-18 Priority to US10/643,154 priority patent/US7680537B2/en
2003-08-18 Priority to US10/643,203 priority patent/US7720541B2/en
2003-08-18 Priority to US10/643,016 priority patent/US7396333B2/en
2003-09-18 Priority to US50422903P priority
2004-03-11 Priority to US10/798,794 priority patent/US7336996B2/en
2004-04-15 Priority to US10/824,776 priority patent/US7510531B2/en
2004-06-09 Priority to US10/864,287 priority patent/US7469697B2/en
2004-08-17 Priority to US10/920,568 priority patent/US20050080348A1/en
2004-08-17 Priority to US10/920,569 priority patent/US7572225B2/en
2004-08-17 Priority to US10/920,549 priority patent/US20050107838A1/en
2004-08-17 Priority to US10/920,675 priority patent/US8606356B2/en
2004-08-19 Priority to US10/922,351 priority patent/US7364547B2/en
2004-08-30 Priority to US10/929,830 priority patent/US7970470B2/en
2004-08-30 Priority to US10/929,826 priority patent/US7468040B2/en
2004-08-30 Priority to US10/929,306 priority patent/US8251061B2/en
2004-08-31 Priority to US10/930,508 priority patent/US7575553B2/en
2004-08-31 Priority to US10/930,979 priority patent/US7591265B2/en
2004-09-13 Priority to US10/939,834 priority patent/US7887493B2/en
2004-09-13 Priority to US10/939,639 priority patent/US7616988B2/en
2004-09-15 Priority to US10/943,070 priority patent/US7302295B2/en
2004-09-15 Priority to US10/943,074 priority patent/US7967756B2/en
2004-09-17 Priority to US10/943,721 priority patent/US7787946B2/en
2004-09-17 Application filed by Cardiac Pacemakers Inc filed Critical Cardiac Pacemakers Inc
2005-01-31 Assigned to CARDIAC PACEMAKERS, INC. reassignment CARDIAC PACEMAKERS, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SIEJKO, KRZYSZTOF K., ZHU, QINGSHENG, HARTHEY, JESS D., HATLESTAD, JOHN D., LEE, KENT, NI, QUAN, STAHMANN, JEFFREY E.
2005-03-09 Assigned to CARDIAC PACEMAKERS, INC. reassignment CARDIAC PACEMAKERS, INC. CORRECTIVE ASSIGNMENT TO CORRECT THE SPELLING OF THE ASSIGNOR'S NAMES, PREVIOUSLY RECORDED ON REEL 015635, FRAME 0921. Assignors: SIEJKO, KRZYSZTOF Z., ZHU, QINGSHENG, HARTLEY, JESSE W., HATLESTAD, JOHN D., LEE, KENT, NI, QUAN, STAHMANN, JEFFREY E.
2005-06-02 Publication of US20050115561A1 publication Critical patent/US20050115561A1/en
2010-08-31 Publication of US7787946B2 publication Critical patent/US7787946B2/en
This application claims the benefit of Provisional Patent Application Ser. No. 60/504,229, filed on Sep. 18, 2003 (GUID.151P1), to which priority is claimed pursuant to 35 U.S.C. §119(e) and which is hereby incorporated herein by reference.
According to various embodiments of the invention, a system may be implemented to include an implantable device configured to perform at least one cardiac-related function and a patient-external respiratory therapy device. A communication channel may be configured to facilitate communication between the implantable device and the respiratory therapy device. The implantable and respiratory therapy devices may be configured to operate cooperatively via the communication channel to provide one or more of patient monitoring, diagnosis, and therapy. The communication channel may be configured to facilitate unidirectional or bidirectional communication between the implantable device and the respiratory therapy device.
The communication channel may be configured to facilitate communication between the implantable device and the respiratory therapy device. The communication channel may be configured to facilitate unidirectional, bidirectional, or a combination of uni- and bi-directional communication between the processing system and one or both of the implantable and respiratory therapy devices.
The processing system may be configured to coordinate one or more of initiation, modification, and termination of a monitoring procedure performed by one or both of the implantable and respiratory therapy devices : One or both of the implantable and respiratory therapy devices may be configured to coordinate a function of the processing system. The processing system may be configured to remotely interrogate one or both of the implantable and respiratory therapy devices.
FIG. 40is a block diagram of a sleep logbook system in accordance with embodiments of the invention;
FIGS. 48G 18J are block diagrams of external respiratory therapy devices having one or more electrodes mechanically coupled to the respiratory therapy mask assembly and used in connection with detecting cardiac events in accordance with embodiments of the invention;
FIGS. 71A and 71Bare block diagrams of medical systems that may be used to implement therapy control based on cardiopulmonary status assessment in accordance with embodiments of the invention;
Methods, devices, and systems implementing a coordinated approach to patient monitoring, diagnosis, and /or therapy in accordance with the present invention may incorporate one or more of the features, structures, methods, or combinations thereof described herein below. For example, a medical system maybe implemented to include one or more of the features and/or processes described below. It is intended that such a method, device, or system need not include all of the features and functions described herein, but may be implemented to include one or more selected features and functions that provide useful structures and/or functionality.
The data stored on the APM patient information server 170 may be accessible by the patient and the patient's physician through terminals 150, e.g., remote computers located in the patient's home or the physician's office. The APM patient information server 170 may be used to communicate to one or more of the patient-internal and patient-external medical devices 110,120 to effect remote control of the monitoring, diagnosis, and/or therapy functions of the medical devices 110, 120.
Coordinated use of two or more medical procedures typically involves transfer of some form of information, such as data and/or control signals, that is used by, or influences the behavior of the medical procedures or devices implementing such medical procedures. The transfer of information may implicate one of the medical procedures, some of the medical procedures, or all of the medical procedures. The transfer of information may implicate other processes that interact with one or more medical procedures, such as processes implemented by a patient-external processing system. The transfer of information may be unidirectional or bidirectional with respect to medical procedures and/or other processes.
As indicated in FIG. 1A, one or both of the devices 110, 120 of the medical system 100 may include a monitoring unit 112, 153, a diagnostics unit 114, 154, and a therapy unit 116, 155. Each ofthese units 112, 114, 116, 153, 154, 155 may be used alone or in cooperation with other components of the medical system 100 to implement the various medical procedures 180.
Contextual/ Environmental Ambient Thermometer
Non- temperature
One or both of the medical devices 210, 220 of FIG. 2A may include a monitoring unit, as previously described in connection with FIG. 1A, that processes signals from one or more of the sensors or other data acquisition devices. The monitoring unit may include processes to detect the occurrence of various events, including, for example, normal and/or abnormal physiological system events or condition, cardiovascular system events, a respiratory system events, muscle system events, nervous system event, and/or a sleep-related events. Other types of events may also be detected. For example, detection of a cardiovascular system event may involve detection of detect abnormal or unusual events of the cardiovascular system such as ventricular tachycardia or fibrillation. The detection of a cardiovascular system event may alternatively involve detection of normal cardiac beats or other events or conditions associated with the usual functioning of the heart.
Respiratory event detection may involve events or conditions associated with various respiratory system disorders, such as a disordered breathing event or a pulmonary congestion condition. Respiratory system event/condition detection may also be used to detect the inspiratory and expiratory phases of normal respiration cycles, for example.
Muscle system event/condition detection may involve detection of abnormal limb movements, such as those associated with periodic limb movement disorder (PLMD), for example. Muscle system event/condition detection may further be used to detect normal or abnormal conditions, such as normal muscle atonia associated with REM sleep or abnormal muscle tone of the upper airway associated with obstructive sleep apnea events. The muscle system event/condition detection may also be used, for example, to detect the level of patient activity. Patient activity information may be useful, for example, in assessing the overall activity level of the patient, or determining if the patient is asleep.
Detection of nervous system events may comprise, for example, detection arousals for sleep, or detection of brain wave activity events. Sleep-related events such as sleep onset, sleep offset, sleep stages, arousals from sleep sleep disordered breathing events, and nocturnal movements may be monitored in connecting with sleep quality assessment.
Information related to parameter or conditions affecting the patient may be stored in memory. The stored data may be transmitted to another component of the medical devices 210, 220 or to a separate device for storage, further processing, trending, analysis and/or display, for example. In one scenario, the stored data can be downloaded to a separate device periodically or on command. The stored data may be presented to the patient's health care professional on a real-time basis, or as a long-term, e.g., month long or year long, trend of daily measurements.
One or both of the devices 210, 220 may include the capability of assessing disease presence and/or diagnosing various diseases or disorders. The diagnostics capability of the medical devices 210, 220 may rely on information acquired and stored in memory over a period of time. Diagnostics or assessments of disease presence may involve evaluation of events or conditions detected by the monitoring/detection components of the devices 210, 220.
One or both medical devices 210, 220 may include the ability to deliver or control the delivery of therapy to a patient. In the example provided in FIG. 2A, the cardiac device 210 may deliver cardiac electrical stimulation therapy using a cardiac pulse generator and electrical stimulation electrodes.
The respiratory therapy device 220 may delivery any of a variety of respiration therapies, including, for example, continuous positive airway pressure (CPAP), bi-level positive airway pressure (bi-PAP), proportional positive airway pressure (PPAP), auto-titrating positive airway pressure, ventilation, gas, pharmacological agent, or oxygen therapies, among others.
One of the devices 210, 220 may partially or fully control the therapy delivered by the other device 220, 210. For example, the cardiac device 210 may control or aid in the control of therapy delivered by the respiratory device 220. The respiratory device 220 may control or aid in the control of therapy delivered by the cardiac device 210.
One or both of the medical devices 210, 220 may fully or partially control other therapy delivery devices or receive input from other sensors. For example, one or both of the medical devices 210, 220 may be used to control a drug therapy device, such as a drug pump, a controllable nebulizer, and/or electrically activated drug patch. In a further example, one or both of the medical devices 210, 220 may be used to control a nerve stimulation or muscle stimulation therapy device, such as a hypoglossal or phrenic nerve stimulation device.
In one implementation, illustrated in FIG. 2A, the medical system 200 includes a uni-directional or bidirectional communications channel 241 between the medical devices 210, 220. The communications channel 241 facilitates the cooperation between the medical devices 210, 220. The communications channel 241 may be implemented as a wireless link between the cardiac device 210 and the respiratory therapy device 220. The wireless communication channel 241 coupling the medical devices 210, 220 may utilize a variety of wireless protocols, including, for example, Bluetooth, IEEE 802.11, and/or a proprietary wireless protocol.
In another implementation, illustrated in FIG. 2B, the medical system 201 includes an external processor 230. The external processor 230 may comprise, for example, an advanced patient management system, as previously described. The external processor 230 may acquire patient conditions or parameters 232, store patient information, provide monitoring and/or diagnostic functionality 231, control therapy 231 delivered by the cardiac and/or respiratory devices 210, 220 and/or other therapy devices.
The external processor may be coupled to one or both of the cardiac and respiratory devices 210, 220 through wireless or wired communications channels 243, 242. In one implementation, the cardiac and respiratory devices 210, 220 may not communicate directly, but may communicate indirectly via the external processor 230.
FIG. 3 illustrates a respiratory therapy device 300 in accordance with embodiments of the invention. Respiratory therapy, such as gas therapy, oxygen therapy, CO2 therapy, positive airway pressure therapy, or other therapies provided to a patient through the pulmonary system, may mitigate a patient's suffering from a number of respiratory disorders. Some lung diseases, such as emphysema, sarcoidosis, and chronic obstructive pulmonary disorder, reduce lung function to the extent that supplemental oxygen is needed to continue normal bodily functions. For many patients with end stage lung disease, oxygen therapy allows the patients to get the oxygen they need, helps them be more active, and may also prevent or treat heart failure. All types of respiratory therapy devices are referred to generically herein as xPAP devices.
The respiratory therapy device 300 may include, for example, any of the positive airway pressure devices, including CPAP, bi-level positive airway pressure (bi-PAP), proportional positive airway pressure (PPAP), and/or autotitration positive airway pressure devices, for example. Continuous positive airway pressure (CPAP) devices deliver a set air pressure to the patient. The pressure level for the individual patient may be determined during a titration study. Such a study may take place in a sleep lab, and involves determination of the optimum airway pressure by a sleep physician or other professional.
The CPAP device pressure control is set to the determined level. When the patient uses the CPAP device, a substantially constant airway pressure level is maintained by the device.
Respiratory therapy may be provided by a servo ventilation device. Servo ventilation devices provide airway pressure dependent on the respiration cycle stage. A servo ventilation device provides positive pressure on inhalation and negative pressure on exhalation.
The respiration therapy control unit 340, illustrated in this example as a positive airway device, includes a flow generator 342 that pulls in air through a filter. The flow generator 342 is controlled by the pressure control circuitry 344 to deliver an appropriate air pressure to the patient. Air flows through tubing 346 coupled to the respiratory device 300 and is delivered to the patient's airway through a mask 348. In one example, the mask 348 may be a nasal mask covering only the patient's nose. In another example, the mask 348 covers the patient's nose and mouth.
The respiratory device 300 includes a communications unit 380 for communicating with one or more separate devices, including patient-external and/or patient-internal monitoring, diagnostic and/or therapeutic devices.
The respiratory therapy device 300 may receive information from one or more data acquisition devices 350, e.g., sensors, patient input devices, and/or other information systems. The acquired information may be used to implement one or more monitoring, diagnostic and/or therapeutic functions 360 of the respiratory therapy device 300. In one example, a monitoring processor 360 may be used to store information related to one or more physiological or nonphysiological parameters acquired over a period of time. In another example, a diagnostics unit may assess the presence of a disease or disorder based on information acquired through use of the data acquisition devices and/or received via the communications channel 370 from a separate device. In yet a further example, therapy delivered by the respiratory therapy device 300 may be controlled by a therapy processor 360. Alternatively or additionally, the therapy processor 360 may control therapy delivered by remote device coupled to the respiratory therapy device 300 via the communications channel 370.
FIG. 4A is a partial view of an implantable cardiac device that may include circuitry for implementing coordinated monitoring, diagnosis and/or therapy in accordance with embodiments of the invention. In this example, the implantable device comprises a cardiac rhythm management device (CRM) 400 including an implantable electrical stimulation generator 405 electrically and physically coupled to an intracardiac lead system 410. Portions of the intracardiac lead system 410 are inserted into the patient's heart 490. The intracardiac lead system 410 includes one or more electrodes configured to sense electrical cardiac activity of the heart, deliver electrical stimulation to the heart, sense the patient's transthoracic impedance, and/or sense other physiological parameters, e,g, cardiac chamber pressure or temperature. Portions of the housing 401 of the pulse generator 405 may optionally serve as a can electrode.
Communications circuitry is disposed within the housing 401 for facilitating communication between the electrical stimulation generator 405 and remote devices having wireless communication functionality, such as a portable or bed-side communication station, patient-carried/worn communication station, or external programmer, for example. The wireless communications circuitry can also facilitate unidirectional or bidirectional communication with one or more implanted, external, cutaneous, or subcutaneous physiologic or non-physiologic sensors, patient-input devices and/or other information systems.
The housing 401 of the electrical stimulation generator 405 may optionally incorporate various sensors, including, for example, a motion sensor that may be programmed to sense various conditions. For example, the motion sensor may be optionally configured to sense snoring, patient activity level, and/or chest wall movements associated with respiratory effort, for example. In one example implementation, the motion detector may be implemented as an accelerometer positioned in or on the housing 401 of the electrical stimulation generator 405. If the motion sensor is implemented as an accelerometer, the motion sensor may also provide respiratory information, e.g. rales, coughing, and cardiac information, e.g. S1-S4 heart sounds, murmurs, and/or other acoustic information.
The lead system 410 of the CRM 400 may incorporate one or more electrodes used to sense transthoracic impedance. Transthoracic impedance sensing may be used to acquire the patient's respiration waveform, or other respiration-related information. Transthoracic impedance may be sensed using one or more intracardiac electrodes 441, 442, 451-455, 463 positioned in one or more chambers of the heart 490. The intracardiac electrodes 441, 442, 451-455, 463 may be coupled to impedance drive/sense circuitry positioned within the housing of the electrical stimulation generator 405.
In one implementation, impedance drive/sense circuitry disposed within the housing 401 generates a current that flows through the tissue between an impedance drive electrode 451 and a can electrode on the housing 401 of the electrical stimulation generator 405. The voltage at an impedance sense electrode 452 relative to the can electrode changes as the patient's transthoracic impedance changes. The voltage signal developed between the impedance sense electrode 452 and the can electrode is detected by the impedance sense circuitry disposed within the housing 401 of the electrical stimulation generator 405. Other locations and/or combinations of impedance sense and drive electrodes are also possible.
The voltage signal developed at the impedance sense electrode 452, illustrated in FIG. 4A, is proportional to the patient's transthoracic impedance and represents the patient's respiration waveform. The transthoracic impedance increases during respiratory inspiration and decreases during respiratory expiration. The peak-to-peak transition of the transthoracic impedance is proportional to the amount of air moved in one breath, denoted the tidal volume. The amount of air moved per minute is denoted the minute ventilation. A normal “at rest” respiration pattern, e.g., during non-REM sleep, includes regular, rhythmic inspiration—expiration cycles without substantial interruptions, as indicated in FIG. 4B.
Returning to FIG. 4A, the lead system 410 may include one or more cardiac pace/sense electrodes 451-455 positioned in, on, or about one or more heart chambers for sensing electrical signals from the patient's heart 490 and/or delivering pacing pulses to the heart 490. The intracardiac sense/pace electrodes 451-455, such as those illustrated in FIG. 4A, may be used to sense and/or pace one or more chambers of the heart, including the left ventricle, the right ventricle, the left atrium and/or the right atrium. The lead system 410 may include one or more defibrillation electrodes 441, 442 for delivering defibrillation/cardioversion shocks to the heart 490.
As described above, the housing 401 of the electrical stimulation generator 405 may include circuitry for detecting cardiac arrhythmias and/or for controlling pacing and/or defibrillation therapy in the form of electrical stimulation pulses or shocks delivered to the heart through the lead system 410. Also disposed within the housing 401 may be various communications circuitry and monitoring, diagnostic, and/or therapy control circuitry that may be used to effect coordinated monitoring, diagnosis and/or therapy in accordance with embodiments of the invention.
In accordance with another embodiment, an implantable transthoracic cardiac sensing and/or stimulation (ITCS) device may be implemented to detect/monitor normal and abnormal cardiac and/or respiratory activity, and may be configured to deliver an appropriate therapy in response to abnormal activity or conditions. An ITCS device 500 of the present invention may be configured for monitoring, diagnosing, and/or treating cardiac and disordered breathing events/conditions. An ITCS device 500 is typically implemented to sense activity of both the cardiac system and the respiratory system. Using appropriate sensors, the ITCS device 500 may be implemented to detect and monitor a variety of disordered breathing conditions, including sleep and non-sleep related disordered breathing conditions. An ITCS device 500 may further be implemented to detect sleep, and may further be implemented to detect stages of patient sleep. An ITCS device 500 so implemented may be configured to perform a variety of sensing, monitoring, diagnosing, and/or therapy control/coordination functions, including those described herein and in the references respectively incorporated herein.
An ITCS device can incorporate circuitry, structures and functionality of the subcutaneous implantable medical devices disclosed in commonly owned U.S. Pat. Nos. 5,203,348; 5,230,337; 5,360,442; 5,366,496; 5,397,342; 5,391,200; 5,545,202; 5,603,732; and 5,916,243 and commonly owned U.S. patent applications Ser. No. 60/462,272, filed Apr. 11, 2003; Ser. No. 10/462,001, filed Jun. 13, 2003; Ser. No. 10/465,520, filed Jun. 19, 2003; Ser. No. 10/785,431, filed Feb. 24, 2004; Ser. No. 10/820,642, filed Apr. 8, 2004; and Ser. No. 10/821,248, filed Apr. 8, 2004, all of which are incorporated herein by reference.
FIG. 5A is a block diagram illustrating various components of an ITCS device 500 that provides for disordered breathing detection and/or treatment in accordance with embodiments of the present invention. In general terms, cardiac activity and disordered breathing (e.g., sleep disordered breathing and wakeful disordered breathing) may be detected, monitored, and/or treated with use of an ITCS device 500, such as the one shown in FIG. 5A. An ITCS device 500 may be implanted under the skin in the chest region of a patient. The ITCS device 500 may, for example, be implanted subcutaneously such that all or selected elements of the device are positioned on the patient's front, back, side, or other body locations suitable for sensing cardiac activity and delivering cardiac stimulation therapy. It is understood that elements of the ITCS device 500 may be located at several different body locations, such as in the chest, abdominal, or subclavian region with electrode elements respectively positioned at different regions near, around, or on the heart.
The primary housing (e.g., the active or non-active can) 502 of the ITCS device 500, for example, may be configured for positioning outside of the rib cage at an intercostal or subcostal location, within the abdomen, or in the upper chest region (e.g., subclavian location, such as above the third rib). In one implementation, one or more electrodes may be located on the primary housing 502 and/or at other locations (e.g., electrode 504) about, but not in direct contact with the heart, great vessels or coronary vasculature. A pulse generator and a cardiac stimulation controller are disposed in the primary housing 502. The cardiac stimulator controller determines and coordinates appropriate cardiac and/or respiratory therapy to be delivered to a patient, and the pulse generator produces the appropriate energy waveforms associated with a selected therapy. Also disposed in the primary housing 502 is a cardiac activity detector configured to detect normal and abnormal (e.g., arrhythmic) cardiac activity.
In a further implementation, one or more subcutaneous electrode subsystems or electrode arrays 504 may be used to sense cardiac activity and deliver cardiac stimulation energy in an ITCS device 500 configuration employing an active can or a configuration employing a non-active can. Electrodes (e.g., electrode 504) may be situated at anterior and/or posterior locations relative to the heart.
The ITCS device 500 depicted in FIG. 5A may be configured in a manner described herein or may have other configurations. An ITCS device 500 of the present invention may be implemented to include one or more of cardiac and/or respiratory detection/monitoring circuitry (e.g., for cardiac activity, breathing patterns such as from transthoracic impedance signals, heart sounds, blood gas/chemistry such as oxygen saturation and/or pH), cardiac and respiratory diagnostics circuitry, and cardiac and respiratory therapy circuitry. An ITCS device 500 of the present invention may be implemented to provide for upgradeability in terms of functionality and/or configuration. For example, an ITCS device 500 may be implemented as an upgradeable or reconfigurable cardiac/respiratory monitor or stimulation device.
An ITCS device 500 in accordance with embodiments of the present invention provides for patient breathing monitoring and disordered breathing detection and/or prediction. Such embodiments may further provide treatment for detected or predicted disordered breathing events or conditions, as determined by a therapy controller or in response to an externally generated command signal (such as received from an advanced patient management system or programmer). Detection and treatment of disordered breathing and/or respiratory conditions may be facilitated by use of an ITCS device 500 having appropriate sensing/detection/therapy delivery capabilities, or by cooperative use of an ITCS device 500 and an external programmer or an advanced patient management system via a communications interface.
With continued reference to FIG. 5A, the ITCS device 500 includes a housing 502 within which various cardiac and respiratory sensing, detection, processing, and energy delivery circuitry may be housed. Communications circuitry is disposed within the housing 502 for facilitating communication between the ITCS device 500 and an external communication device, such as a portable or bed-side communication station, patient-carried/worn communication station, or external programmer, for example. The communications circuitry may also facilitate unidirectional or bidirectional communication with one or more external, cutaneous, or subcutaneous physiologic or non-physiologic sensors. The housing 502 is typically configured to include one or more electrodes (e.g., can electrode and/or indifferent electrode). Although the housing 502 is typically configured as an active can, it is appreciated that a non-active can configuration may be implemented, in which case at least two electrodes spaced apart from the housing 502 are employed.
In the configuration shown in FIG. 5A, a subcutaneous electrode 504 may be positioned under the skin in the chest region and situated distal from the housing 502. The subcutaneous and, if applicable, housing electrode(s) may be positioned about the heart at various locations and orientations, such as at various anterior and/or posterior locations relative to the heart. The subcutaneous electrode 504 is coupled to circuitry within the housing 502 via a lead assembly 506. One or more conductors (e.g., coils or cables) are provided within the lead assembly 506 and electrically couple the subcutaneous electrode 504 with circuitry in the housing 502. One or more sense, sense/pace or defibrillation electrodes may be situated on the elongated structure of the electrode support, the housing 502, and/or the distal electrode assembly (shown as subcutaneous electrode 504 in the configuration shown in FIG. 5A).
In one configuration, the lead assembly 506 is generally flexible and has a construction similar to conventional implantable, medical electrical leads (e.g., defibrillation leads or combined defibrillation/pacing leads). In another configuration, the lead assembly 506 is constructed to be somewhat flexible, yet has an elastic, spring, or mechanical memory that retains a desired configuration after being shaped or manipulated by a clinician. For example, the lead assembly 506 may incorporate a gooseneck or braid system that may be distorted under manual force to take on a desired shape. In this manner, the lead assembly 506 may be shape-fit to accommodate the unique anatomical configuration of a given patient, and generally retains a customized shape after implantation. Shaping of the lead assembly 506 according to this configuration may occur prior to, and during, ITCS device 500 implantation.
In accordance with a further configuration, the lead assembly 506 includes an electrode support assembly, such as an elongated structure that positionally stabilizes the subcutaneous electrode 504 with respect to the housing 502. In this configuration, the rigidity of the elongated structure maintains a desired spacing between the subcutaneous electrode 504 and the housing 502, and a desired orientation of the subcutaneous electrode 104/housing 502 relative to the patient's heart. The elongated structure may be formed from a structural plastic, composite or metallic material, and includes, or is covered by, a biocompatible material. Appropriate electrical isolation between the housing 502 and subcutaneous electrode 504 is provided in cases where the elongated structure is formed from an electrically conductive material, such as metal.
In one configuration, the electrode support assembly and the housing 502 define a unitary structure (e.g., a single housing/unit). The electronic components and electrode conductors/connectors are disposed within or on the unitary ITCS device 500 housing/electrode support assembly. At least two electrodes are supported on the unitary structure near opposing ends of the housing/electrode support assembly. The unitary structure may have an arcuate or angled shape, for example.
According to another configuration, the electrode support assembly defines a physically separable unit relative to the housing 502. The electrode support assembly includes mechanical and electrical couplings that facilitate mating engagement with corresponding mechanical and electrical couplings of the housing 502. For example, a header block arrangement may be configured to include both electrical and mechanical couplings that provide for mechanical and electrical connections between the electrode support assembly and housing 502. The header block arrangement may be provided on the housing 502 or the electrode support assembly. Alternatively, a mechanical/electrical coupler may be used to establish mechanical and electrical connections between the electrode support assembly and housing 502. In such a configuration, a variety of different electrode support assemblies of varying shapes, sizes, and electrode configurations may be made available for physically and electrically connecting to a standard ITCS device 500 housing 502.
It is noted that the electrodes and the lead assembly 506 may be configured to assume a variety of shapes. For example, the lead assembly 506 may have a wedge, chevron, flattened oval, or a ribbon shape, and the subcutaneous electrode 504 may include a number of spaced electrodes, such as an array or band of electrodes. Moreover, two or more subcutaneous electrodes 504 may be mounted to multiple electrode support assemblies 506 to achieve a desired spaced relationship amongst subcutaneous electrodes 504.
FIG. 5B is a block diagram depicting various components of an ITCS device 500 in accordance with one configuration. According to this configuration, the ITCS device 500 incorporates a processor-based control system 505 which includes a micro-processor 526 coupled to appropriate memory (volatile and non-volatile) 509, it being understood that any logic-based control architecture may be used. The control system 505 is coupled to circuitry and components to sense, detect, and analyze electrical signals produced by the heart and deliver electrical stimulation energy to the heart under predetermined conditions to treat cardiac arrhythmias. In certain configurations, the control system 505 and associated components also provide pacing therapy to the heart. The electrical energy delivered by the ITCS device 500 may be in the form of low energy pacing pulses, non-excitatory energy (e.g., sub-threshold stimulation energy) or high-energy pulses for cardioversion or defibrillation.
Cardiac signals are sensed using the subcutaneous electrode(s) 514 and the can or indifferent electrode 507 provided on the ITCS device 500 housing. Cardiac signals may also be sensed using only the subcutaneous electrodes 514, such as in a non-active can configuration. As such, unipolar, bipolar, or combined unipolar/bipolar electrode configurations as well as multi-element electrodes and combinations of noise canceling and standard electrodes may be employed. The sensed cardiac signals are received by sensing circuitry 524, which includes sense amplification circuitry and may also include filtering circuitry and an analog-to-digital (A/D) converter. The sensed cardiac signals processed by the sensing circuitry 524 may be received by noise reduction circuitry 503, which may further reduce noise before signals are sent to the detection circuitry 522.
Noise reduction circuitry 503 may also be incorporated after sensing circuitry 522 in cases where high power or computationally intensive noise reduction algorithms are required. The noise reduction circuitry 503, by way of amplifiers used to perform operations with the electrode signals, may also perform the function of the sensing circuitry 524. Combining the functions of sensing circuitry 524 and noise reduction circuitry 503 may be useful to minimize the necessary componentry and lower the power requirements of the system.
In the illustrative configuration shown in FIG. 5B, the detection circuitry 522 is coupled to, or otherwise incorporates, noise reduction circuitry 503. The noise reduction circuitry 503 operates to improve the signal-to-noise ratio (SNR) of sensed cardiac signals by removing noise content of the sensed cardiac signals introduced from various sources. Typical types of transthoracic cardiac signal noise includes electrical noise and noise produced from skeletal muscles, for example.
Detection circuitry 522 typically includes a signal processor that coordinates analysis of the sensed cardiac signals and/or other sensor inputs to detect cardiac arrhythmias, such as, in particular, tachyarrhythmia. Rate based and/or morphological discrimination algorithms may be implemented by the signal processor of the detection circuitry 522 to detect and verify the presence and severity of an arrhythmic episode.
The detection circuitry 522 communicates cardiac signal information to the control system 505. Memory circuitry 509 of the control system 505 contains parameters for operating in various sensing, defibrillation, and, if applicable, pacing modes, and stores data indicative of cardiac signals received by the detection circuitry 522. The memory circuitry 509 may also be configured to store historical ECG and therapy data, which may be used for various purposes and transmitted to an external receiving device as needed or desired.
In certain configurations, the ITCS device 500 may include diagnostics circuitry 510. The diagnostics circuitry 510 typically receives input signals from the detection circuitry 522 and the sensing circuitry 524. The diagnostics circuitry 510 provides diagnostics data to the control system 505, it being understood that the control system 505 may incorporate all or part of the diagnostics circuitry 510 or its functionality. The control system 505 may store and use information provided by the diagnostics circuitry 510 for a variety of diagnostics purposes. This diagnostic information may be stored, for example, subsequent to a triggering event or at predetermined intervals, and may include system diagnostics, such as power source status, therapy delivery history, and/or patient diagnostics. The diagnostic information may take the form of electrical signals or other sensor data acquired immediately prior to therapy delivery.
According to a configuration that provides cardioversion and defibrillation therapies, the control system 505 processes cardiac signal data received from the detection circuitry 522 and initiates appropriate tachyarrhythmia therapies to terminate cardiac arrhythmic episodes and return the heart to normal sinus rhythm. The control system 505 is coupled to shock therapy circuitry 516. The shock therapy circuitry 516 is coupled to the subcutaneous electrode(s) 514 and the can or indifferent electrode 507 of the ITCS device 500 housing. Upon command, the shock therapy circuitry 516 delivers cardioversion and defibrillation stimulation energy to the heart in accordance with a selected cardioversion or defibrillation therapy. In a less sophisticated configuration, the shock therapy circuitry 516 is controlled to deliver defibrillation therapies, in contrast to a configuration that provides for delivery of both cardioversion and defibrillation therapies.
In accordance with another configuration, an ITCS device 500 may incorporate a cardiac pacing capability in addition to cardioversion and/or defibrillation capabilities. As is shown in dotted lines in FIG. 5B, the ITCS device 500 may include pacing therapy circuitry 530, which is coupled to the control system 505 and the subcutaneous and can/indifferent electrodes 514, 507. Upon command, the pacing therapy circuitry delivers pacing pulses to the heart in accordance with a selected pacing therapy. Control signals, developed in accordance with a pacing regimen by pacemaker circuitry within the control system 505, are initiated and transmitted to the pacing therapy circuitry 530 where pacing pulses are generated. A pacing regimen may be modified by the control system 505.
A number of cardiac pacing therapies may be useful in a transthoracic cardiac monitoring and/or stimulation device. Such cardiac pacing therapies may be delivered via the pacing therapy circuitry 530 as shown in FIG. 5B. Alternatively, cardiac pacing therapies may be delivered via the shock therapy circuitry 516, which effectively obviates the need for separate pacemaker circuitry.
The ITCS device 500 shown in FIG. 5B is configured to receive signals from one or more physiologic and/or non-physiologic sensors. Depending on the type of sensor employed, signals generated by the sensors may be communicated to transducer circuitry coupled directly to the detection circuitry 522 or indirectly via the sensing circuitry 524. It is noted that certain sensors may transmit sense data to the control system 505 without processing by the detection circuitry 522.
Non-electrophysiological cardiac sensors 561 may be coupled directly to the detection circuitry 522 or indirectly via the sensing circuitry 524. Non-electrophysiological cardiac sensors 561 sense cardiac activity that is non-electrophysiological in nature. Examples of non-electrophysiological cardiac sensors 561 include blood oxygen sensors, transthoracic impedance sensors, blood volume sensors, acoustic sensors and/or pressure transducers, and accelerometers. Signals from these sensors are developed based on cardiac activity, but are not derived directly from electrophysiological sources (e.g., R-waves or P-waves). A non-electrophysiological cardiac sensor 561, as is illustrated in FIG. 5B, may be connected to one or more of the sensing circuitry 524, detection circuitry 522 (connection not shown for clarity), and the control system 505.
Communications circuitry 518 is coupled to the microprocessor 526 of the control system 505. The communications circuitry 518 allows the ITCS device 500 to communicate with one or more receiving devices or systems situated external to the ITCS device 500. By way of example, the ITCS device 500 may communicate with a patient-worn, portable or bedside communication system via the communications circuitry 518. In one configuration, one or more physiologic or non-physiologic sensors (subcutaneous, cutaneous, or external of patient) may be equipped with a short-range wireless communication interface, such as an interface conforming to a known communications standard, such as Bluetooth or IEEE 802 standards. Data acquired by such sensors may be communicated to the ITCS device 500 via the communications circuitry 518. It is noted that physiologic or non-physiologic sensors equipped with wireless transmitters or transceivers may communicate with a receiving system external of the patient.
The communications circuitry 518 may allow the ITCS device 500 to communicate with an external programmer. In one configuration, the communications circuitry 518 and the programmer unit (not shown) use a wire loop antenna and a radio frequency telemetric link, as is known in the art, to receive and transmit signals and data between the programmer unit and communications circuitry 518. In this manner, programming commands and data are transferred between the ITCS device 500 and the programmer unit during and after implant. Using a programmer, a physician is able to set or modify various parameters used by the ITCS device 500. For example, a physician may set or modify parameters affecting sensing, detection, pacing, and defibrillation functions of the ITCS device 500, including pacing and cardioversion/defibrillation therapy modes.
Typically, the ITCS device 500 is encased and hermetically sealed in a housing suitable for implanting in a human body as is known in the art. Power to the ITCS device 500 is supplied by an electrochemical power source 520 housed within the ITCS device 500. In one configuration, the power source 520 includes a rechargeable battery. According to this configuration, charging circuitry is coupled to the power source 520 to facilitate repeated non-invasive charging of the power source 520. The communications circuitry 518, or separate receiver circuitry, is configured to receive RF energy transmitted by an external RF energy transmitter. The ITCS device 500 may, in addition to a rechargeable power source, include a non-rechargeable battery. It is understood that a rechargeable power source need not be used, in which case a long-life non-rechargeable battery is employed.
The components, functionality, and structural configurations depicted in FIGS. 5A-5E are intended to provide an understanding of various features and combination of features that may be incorporated in an ITCS device 500. It is understood that a wide variety of ITCS and other implantable cardiac monitoring and/or stimulation device configurations are contemplated, ranging from relatively sophisticated to relatively simple designs. As such, particular ITCS or cardiac monitoring and/or stimulation device configurations may include particular features as described herein, while other such device configurations may exclude particular features described herein.
In accordance with embodiments of the invention, an ITCS device 500 may be implemented to include a subcutaneous electrode system that provides for one or both of cardiac sensing and arrhythmia therapy delivery. According to one approach, an ITCS device 500 may be implemented as a chronically implantable system that performs monitoring, diagnostic and/or therapeutic functions. The ITCS device 500 may automatically detect and treat cardiac arrhythmias.
In one configuration, an ITCS device 500 includes a pulse generator and one or more electrodes that are implanted subcutaneously in the chest region of the body, such as in the anterior thoracic region of the body. The ITCS device 500 may be used to provide atrial and/or ventricular therapy for bradycardia and tachycardia arrhythmias. Tachyarrhythmia therapy may include cardioversion, defibrillation and anti-tachycardia pacing (ATP), for example, to treat atrial or ventricular tachycardia or fibrillation. Bradycardia therapy may include temporary post-shock pacing for bradycardia or asystole.
In one configuration, an ITCS device 500 according to one approach may utilize conventional pulse generator and subcutaneous electrode implant techniques. The pulse generator device and electrodes may be chronically implanted subcutaneously. Such an ITCS may be used to automatically detect and treat arrhythmias similarly to conventional implantable systems. In another configuration, the ITCS device 500 may include a unitary structure (e.g., a single housing/unit). The electronic components and electrode conductors/connectors are disposed within or on the unitary ITCS device 500 housing/electrode support assembly.
The ITCS device 500 contains the electronics and may be similar to a conventional implantable defibrillator. High voltage shock therapy may be delivered between two or more electrodes, one of which may be the pulse generator housing (e.g., can), placed subcutaneously in the thoracic region of the body.
Additionally or alternatively, the ITCS device 500 may also provide lower energy electrical stimulation for bradycardia therapy. The ITCS device 500 may provide brady pacing similarly to a conventional pacemaker. The ITCS device 500 may provide temporary post-shock pacing for bradycardia or asystole. Sensing and/or pacing may be accomplished using sense/pace electrodes positioned on an electrode subsystem also incorporating shock electrodes, or by separate electrodes implanted subcutaneously.
The ITCS device 500 may detect a variety of physiological signals that may be used in connection with various diagnostic, therapeutic or monitoring implementations in accordance with the present invention. For example, the ITCS device 500 may include sensors or circuitry for detecting pulse pressure signals, blood oxygen level, heart sounds, cardiac acceleration, and other non-electrophysiological signals related to cardiac activity. In one embodiment, the ITCS device 500 senses intrathoracic impedance, from which various respiratory parameters may be derived, including, for example, respiratory tidal volume and minute ventilation. Sensors and associated circuitry may be incorporated in connection with an ITCS device 500 for detecting one or more body movement or body position related signals. For example, accelerometers and GPS devices may be employed to detect patient activity, patient location, body orientation, or torso position.
The ITCS device 500 may be used within the structure of an APM system. APM systems may allow physicians to remotely and automatically monitor cardiac and respiratory functions, as well as other patient conditions. In one example, implantable cardiac rhythm management systems, such as cardiac pacemakers, defibrillators, and resynchronization devices, may be equipped with various telecommunications and information technologies that enable real-time data collection, diagnosis, and treatment of the patient. Various embodiments described herein may be used in connection with advanced patient management.
An ITCS device 500 according to one approach provides an easy to implant therapeutic, diagnostic or monitoring system. The ITCS system may be implanted without the need for intravenous or intrathoracic access, providing a simpler, less invasive implant procedure and minimizing lead and surgical complications. In addition, this system would have advantages for use in patients for whom transvenous lead systems cause complications. Such complications include, but are not limited to, surgical complications, infection, insufficient vessel patency, complications associated with the presence of artificial valves, and limitations in pediatric patients due to patient growth, among others. An ITCS system according to this approach is distinct from conventional approaches in that it may be configured to include a combination of two or more electrode subsystems that are implanted subcutaneously in the anterior thorax.
In one ITCS system configuration, as is illustrated in FIG. 5C, electrode subsystems of the ITCS system include a first electrode subsystem, including a can electrode 533, and a second electrode subsystem 535 that may include at least one coil electrode, for example. The second electrode subsystem 535 may include a number of electrodes used for sensing and/or electrical stimulation. In various configurations, the second electrode subsystem 535 may include a single electrode or a combination of electrodes. The single electrode or combination of electrodes including the second electrode subsystem 535 may include coil electrodes, tip electrodes, ring electrodes, multi-element coils, spiral coils, spiral coils mounted on non-conductive backing, and screen patch electrodes, for example. A suitable non-conductive backing material is silicone rubber, for example.
The can electrode 533 is located on the housing 531 that encloses the ITCS device 500 electronics. In one embodiment, the can electrode 533 includes the entirety of the external surface of housing 531. In other embodiments, various portions of the housing 531 may be electrically isolated from the can electrode 533 or from tissue. For example, the active area of the can electrode 533 may include all or a portion of either the anterior or posterior surface of the housing 531 to direct current flow in a manner advantageous for cardiac sensing and/or stimulation.
The housing 531 may resemble that of a conventional implantable ICD, is approximately 20-100 cc in volume, with a thickness of 0.4 to 2 cm and with a surface area on each face of approximately 30 to 100 cm2. As previously discussed, portions of the housing may be electrically isolated from tissue to optimally direct current flow. For example, portions of the housing 531 may be covered with a non-conductive, or otherwise electrically resistive, material to direct current flow. Suitable non-conductive material coatings include those formed from silicone rubber, polyurethane, or parylene, for example.
FIG. 5C illustrates the housing 531 and can electrode 533 placed subcutaneously, superior to the heart 540 in the left pectoral region, which is a location commonly used for conventional pacemaker and defibrillator implants. The second electrode subsystem 535 may include a coil electrode mounted on the distal end of a lead body 537, where the coil is approximately 3-15 French in diameter and 5-12 cm in length. The coil electrode may have a slight preformed curve along its length. The lead may be introduced through the lumen of a subcutaneous sheath, through a common tunneling implant technique, and the second electrode subsystem 535, e.g., including a coil electrode, may be placed subcutaneously, deep to any subcutaneous fat and adjacent to the underlying muscle layer.
In this configuration, the second electrode subsystem 535 is located approximately parallel with the inferior aspect of the right ventricle of the heart 540, just inferior to the right ventricular free wall, with one end extending just past the apex of the heart 540. For example, the tip of the electrode subsystem 535 may extend less than about 3 cm and may be about 1-2 cm left lateral to the apex of the heart 540. This electrode arrangement may be used to include a majority of ventricular tissue within a volume defined between the housing 531 and the second electrode subsystem 535. In one configuration, a majority of the ventricular tissue is included within a volume associated with an area bounded by lines drawn between the distal and proximal ends of the second electrode subsystem 535 and the medial and lateral edges of the left pectoral can electrode 533.
In one example arrangement, the volume including a majority of ventricular tissue may be associated with a cross sectional area bounded by lines drawn between the ends of the electrode subsystems 533, 535 or between active elements of the electrode subsystems 533, 535. In one implementation, the lines drawn between active elements of the electrode subsystems 533, 535 may include a medial edge and a lateral edge of the can electrode 533, and a proximal end and a distal end of a coil electrode utilized within the second electrode subsystem 535. Arranging the electrode subsystems so that a majority of ventricular tissue is contained within a volume defined between the active elements of the electrode subsystems 533, 535 provides an efficient position for defibrillation by increasing the voltage gradient in the ventricles of the heart 540 for a given applied voltage between electrode subsystems 533, 535.
In a similar configuration, and as shown in FIG. 5D, the housing 531 including the can electrode 533 is placed in the right pectoral region. The second electrode subsystem 535 is located more laterally, to again include a majority of the ventricular tissue in a volume defined between the can electrode 533 and the second electrode subsystem 535.
In a further configuration, and as shown in FIG. 5E, the ITCS device housing 531 containing the electronics (i.e., the can) is not used as an electrode. In this case, an electrode system including two electrode subsystems 538, 539 coupled to the housing 531 may be implanted subcutaneously in the chest region of the body, such as in the anterior thorax. The first and the second electrode subsystems 538, 539 are placed in opposition with respect to the ventricles of the heart 540, with the majority of the ventricular tissue of the heart 540 included within a volume defined between the electrode subsystems 538, 539. As illustrated in FIG. 5E, the first electrode system 538 is located superior to the heart 540 relative to a superior aspect of the heart 540, e.g., parallel to the left ventricular free wall. The second electrode system 539 is located inferior to the heart 540 and positioned in relation to an inferior aspect of the heart 540, e.g., parallel to the right ventricular free wall.
In this configuration, the first and the second electrode subsystems 538, 539 may include any combination of electrodes, including or excluding the can electrode, used for sensing and/or electrical stimulation. In various configurations, the electrode subsystems 538, 539 may each be a single electrode or a combination of electrodes. The electrode or electrodes including the first and second electrode subsystems 538, 539 may include any combination of one or more coil electrodes, tip electrodes, ring electrodes, multi-element coils, spiral coils, spiral coils mounted on non-conductive backing, and screen patch electrodes, for example.
FIGS. 5F-5H provide additional detailed views of subcutaneous electrode subsystem placement considered particularly useful with ITCS devices incorporating disordered breathing detection in accordance with embodiments of the present invention. FIG. 5F illustrates first and second electrode subsystems configured as a can electrode 562 and a coil electrode 564, respectively. FIG. 5F illustrates the can electrode 562 located superior to the heart 560 in the left pectoral region and the coil electrode 564 located inferior to the heart 560, parallel to the right ventricular free wall of the heart 560.
The can electrode 562 and the coil electrode 564 are located so that the majority of ventricular tissue is included within a volume defined between the can electrode 562 and the coil electrode 564. FIG. 5F illustrates a cross sectional area 565 formed by the lines drawn between active elements of the can electrode 562 and the coil electrode 564. Lines drawn between active areas of the electrodes 562, 564, may be defined by a medial edge and a lateral edge of the can electrode 562, and a proximal end and a distal end of a coil electrode utilized as the second electrode subsystem 564. The coil electrode 564 extends a predetermined distance beyond the apex of the heart 560, e.g. less than about 3 cm.
A similar configuration is illustrated in FIG. 5G. In this embodiment, the can electrode 562 is placed superior to the heart 560 in the right pectoral region. The coil electrode 564 is located inferior to the heart. In one arrangement, the coil electrode is located relative to an inferior aspect of the heart 560, for example, the apex of the heart. The can electrode 562 and the coil electrode 564 are positioned so that the majority of ventricular tissue is included within a volume defined between the can electrode 562 and the coil electrode 564.
FIG. 5G illustrates a cross sectional area 565 formed by the lines drawn between active elements of the can electrode 562 and the coil electrode 564. Lines drawn between active areas of the electrodes 562, 564, may be defined by a medial edge and a lateral edge of the can electrode 562, and a proximal end and a distal end of a coil electrode utilized as the second electrode subsystem 564. The coil electrode 564 extends a predetermined distance beyond the apex of the heart 560, e.g. less than about 3 cm.
FIG. 5H illustrates a configuration wherein the pulse generator housing 561 does not include an electrode. In this implementation two electrode subsystems are positioned about the heart so that a majority of ventricular tissue is included within a volume defined between the electrode subsystems. According to this embodiment, the first and second electrodes are configured as first and second coil electrodes 568, 569.
The first coil electrode 568 is located superior to the heart 560 and may be located relative to a superior aspect of the heart, e.g., the left ventricular free wall. The second coil electrode 569 is located inferior to the heart 560. The second electrode 569 may be located in relation to an inferior aspect of the heart 560. In one configuration, the second electrode 569 is positioned parallel to the right ventricular free wall with a tip of the electrode 569 extending less than about 3 cm beyond the apex of the heart 560. As illustrated in FIG. 5H, the volume defined between the electrodes may be defined by the cross sectional area 565 bounded by lines drawn