METHODS AND SYSTEMS FOR IMPROVED COMMUNICATION BETWEEN MEDICAL DEVICES
At least one of a first medical device and a second medical device may be implanted within a patient while the second medical device may optionally be proximate but external to the patient. At least one of the medical devices has an antenna having at least two electrodes and at least one of the medical devices has an antenna having at least three electrodes. The medical devices can communicate via conducted communication through the patient's tissue between a first pair of electrodes and a second pair of electrodes. At least one of the pairs of electrodes can be selected in accordance with the signal strength of the communication vector between the first and second pairs of electrodes.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/926,101 filed Jan. 10, 2014 entitled “METHODS AND SYSTEMS FOR IMPROVED COMMUNICATION BETWEEN MEDICAL DEVICES”, which application is incorporated herein by reference in its entirety.
TECHNICAL FIELDThe present disclosure generally relates to communication between medical devices, and more particularly, to methods and systems for improved communication between medical devices.
BACKGROUNDPacing instruments can be used to treat patients suffering from various heart conditions that may result in a reduced ability of the heart to deliver sufficient amounts of blood to a patient's body. These heart conditions may lead to rapid, irregular, and/or inefficient heart contractions. To help alleviate some of these conditions, various devices (e.g., pacemakers, defibrillators, etc.) can be implanted in a patient's body. Such devices may monitor and provide electrical stimulation to the heart to help the heart operate in a more normal, efficient and/or safe manner. In some cases, a patient may have multiple devices that operate together to detect and/or treat various conditions.
SUMMARYThe present disclosure generally relates to communication between medical devices, and more particularly, to methods and systems for improved communication between medical devices. For example, a first medical device and a second medical device may be implanted within a patient, or the first medical device may be implanted within the patient and the second medical device may be proximate but external to the patient. At least one of the medical devices may have an antenna with at least two electrodes, and at least one of the medical devices may have an antenna with at least three electrodes. The medical devices may communicate by transmitting signals from two of the electrodes of the transmitting medical device to at least two electrodes of the receiving medical device. It is contemplated that the medical devices may communicate via radiofrequency (RF) communication, inductive coupling, conducted communication, or any other suitable communication technique.
It will be appreciated that the relative signal strength between any two pairs of electrodes, such as a first pair of electrodes belonging to the transmitting medical device and a second pair of electrodes belonging to the receiving medical device, may depend in part on the orientation of the receiving electrodes relative to the electromagnetic field produced by the transmitting electrodes. The system may be configured to select a particular pair of electrodes for the transmitting medical device and/or the receiving medical device in order help improve the signal strength of communication between the devices. The different combination of electrodes that may be used for communication between medical devices can each be referred to a “communication vector”. In some instances, various communication vectors may be tested, and the communication vector that produces the highest relative signal strength and/or signal-to-noise ratio may be selected for subsequent communication. Various communication vectors may be re-tested periodically, upon command, when the relative signal strength and/or signal-to-noise ratio falls below a threshold, when the relative signal strength and/or signal-to-noise ratio changes by a threshold, and/or at any other suitable time as desired.
An example method of communicating between a first medical device having a first antenna and a second medical device having a second antenna is disclosed. The first medical device is implanted within a patient and the second medical device is proximate to the patient, and the first antenna and/or the second antenna has at least three electrodes and the other antenna has at least two electrodes. The example method comprises:
selecting a first electrode pair of the antenna that has at least three electrodes;
at least one of sending and receiving a conducted communication signal through tissue of the patient between the first electrode pair of the antenna that has at least three electrodes and two of the electrodes of the other antenna;
selecting a second electrode pair of the antenna that has at least three electrodes, wherein the second electrode pair is different from the first electrode pair; and
sending a conducted communication signal through tissue of the patient between the second electrode pair of the antenna that has at least three electrodes and two electrodes of the other antenna.
Alternatively or additionally to any of the embodiments above, the method may further include:
monitoring a measure related to a signal to noise ratio of the conducted communication signal using the first electrode pair;
if the measure related to a signal to noise ratio of the conducted communication signal using the first electrode pair falls below a threshold, then:
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- selecting the second electrode pair of the antenna that has at least three electrodes; and
- sending the conducted communication signal through tissue of the patient between the second electrode pair of the antenna that has at least three electrodes and the two electrodes of the other antenna.
Alternatively or additionally to any of the embodiments above, the method may further include:
determining a first measure related to a signal to noise ratio of the conducted communication signal using the first electrode pair;
determining a second measure related to a signal to noise ratio of the conducted communication signal using the second electrode pair; and
selecting the first electrode pair or the second electrode pair for subsequent communication based on the first measure and the second measure.
Alternatively or additionally to any of the embodiments above, the second medical device may be implanted within the patient but spaced from the first medical device.
Alternatively or additionally to any of the embodiments above, the second medical device may be disposed outside of the patient and the second antenna is positioned on a skin surface of the patient.
Alternatively or additionally to any of the embodiments above, the antenna that has at least three electrodes may comprise three electrodes that are arranged in a triangular configuration.
Alternatively or additionally to any of the embodiments above, the antenna that has at least three electrodes may comprise four electrodes that are arranged in a rectangular configuration.
Alternatively or additionally to any of the embodiments above, the antenna that has at least three electrodes may comprise four electrodes that are arranged in a kite configuration.
Another example method of communicating between a first medical device having a first antenna with at least two electrodes and a second medical device having a second antenna with at least three electrodes comprises:
testing communication vectors between the at least two electrodes of the first antenna and each of a plurality of pairs of electrodes of the at least three electrodes of the second antenna;
selecting a communication vector based on signal strengths of each of the communication vectors; and
at least one of sending and receiving a conducted communication between the first medical device and the second medical device using the selected communication vector.
Alternatively or additionally to any of the embodiments above, the first medical device may comprise an implanted medical device and the second medical device may comprise an external device.
Alternatively or additionally to any of the embodiments above, the first medical device may comprise an external device and the second medical device may comprise an implanted medical device.
Alternatively or additionally to any of the embodiments above, the first medical device may comprise a first implanted medical device and the second medical device may comprise a second implanted medical device.
Alternatively or additionally to any of the embodiments above, selecting a communication vector may comprise selecting the communication vector with the strongest signal strength.
Alternatively or additionally to any of the embodiments above, selecting a communication vector may comprise not selecting the communication vector with the weakest signal strength.
An example communications system is also disclosed. The example communications system comprises:
a first medical device in communication with a first antenna having at least two electrodes; and
a second medical device in communication with a second antenna having at least three electrodes;
wherein at least one of the first medical device and the second medical device is configured to:
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- test communication vectors between the at least two electrodes of the first antenna and at least two pairs of the at least three electrodes of the second antenna;
- select a communication vector from the tested communication vectors; and
- at least one of send and receive a conducted communication along the selected communication vector.
Alternatively or additionally to any of the embodiments above, the at least three electrodes may comprise three electrodes that are arranged in a triangular configuration.
Alternatively or additionally to any of the embodiments above, the at least three electrodes may comprise four electrodes that are arranged in a rectangular configuration.
Alternatively or additionally to any of the embodiments above, the at least three electrodes may comprise four electrodes that are arranged in a kite configuration.
Alternatively or additionally to any of the embodiments above, at least one of the first medical device and the second medical device may be implanted within a patient.
Alternatively or additionally to any of the embodiments above, the first medical device is a leadless cardiac pacemaker (LCP).
The above summary is not intended to describe each embodiment or every implementation of the present disclosure. Advantages and attainments, together with a more complete understanding of the disclosure, will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.
The disclosure may be more completely understood in consideration of the following description of various illustrative embodiments in connection with the accompanying drawings, in which:
While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular illustrative embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.
DETAILED DESCRIPTIONThe following description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure.
A normal, healthy heart induces contraction by conducting intrinsically generated electrical signals throughout the heart. These intrinsic signals cause the muscle cells or tissue of the heart to contract. This contraction forces blood out of and into the heart, providing circulation of the blood throughout the rest of the body. However, many patients suffer from cardiac conditions that affect the contractility of their hearts. For example, some hearts may develop diseased tissues that no longer generate or conduct intrinsic electrical signals. In some examples, diseased cardiac tissues conduct electrical signals at differing rates, thereby causing an unsynchronized and inefficient contraction of the heart. In other examples, a heart may generate intrinsic signals at such a low rate that the heart rate becomes dangerously low. In still other examples, a heart may generate electrical signals at an unusually high rate. In some cases such an abnormality can develop into a fibrillation state, where the contraction of the patient's heart is almost completely de-synchronized and the heart pumps very little to no blood.
Many medical device systems have been developed to assist patients who experience such abnormities. For example, systems have been developed to sense intrinsic cardiac electrical signals and, based on the sensed electrical signals, determine whether the patient is suffering from one or more arrhythmias. Such systems may also include the ability to deliver electrical stimulation to the heart of the patient in order to treat the detected arrhythmias. In one example, some medical device systems include the ability to identify when the heart is beating at too low of a rate, termed bradycardia. Such systems may deliver electrical stimulation therapy, or “pacing” pulses, that cause the heart to contract at a higher, safer rate. Some medical device systems are able to determine when a heart is beating at too fast of a rate, termed tachycardia. Such systems may further include one or more anti-tachycardia pacing (ATP) therapies. One such ATP therapy includes delivering electrical stimulation pulses to the heart at a rate faster than the intrinsically generated signals. Although this may temporarily cause the heart to beat faster, such a stimulation protocol may cause the heart to contract in response to the delivered pacing pulses as opposed to the intrinsically generated signals. The ATP therapy may then slow down the rate of the delivered pacing pulses, thereby reducing the heart rate to a lower, safer level.
Other medical device systems may be able to detect fibrillation states and asynchronous contractions. For example, based on the sensed signals, some systems may be able to determine when the heart is in a fibrillation state. Such systems may further be configured to treat such fibrillation states with electrical stimulation therapy. One such therapy includes deliver of a relatively large amount of electrical energy to the heart (a “defibrillation pulse”) with the goal of overpowering any intrinsically generated signals.
Such a therapy may “reset” the heart, from an electrical standpoint, which may allow for normal electrical processes to take over. Other medical systems may be able to sense that intrinsically generated signals are generated at differing times or that the heart conducts such signals at differing rates. These abnormalities may result in an unsynchronized, inefficient cardiac contraction. The system may further include the ability to administer one or more cardiac resynchronization therapies (CRTs). One such CRT may include delivering electrical stimulation to the heart at differing locations on and/or within the heart. Such methods may help the disparate parts of the heart to contract near simultaneously, or in a synchronized manner if the system delivers the electrical stimulation to the disparate locations at differing times. The present disclosure relates generally to systems and methods for coordinating detection and/or treatment of abnormal heart activity using multiple implanted devices within a patient. In some instances, a medical device system may include a plurality of devices for detecting cardiac arrhythmias and delivering electrical stimulation therapy. For example, illustrative systems may include devices such as subcutaneous cardioverter-defibrillators (S-ICD), external cardioverter-defibrillators, implantable cardiac pacemakers (ICP), leadless cardiac pacemakers (LCPs), and/or diagnostic only devices (devices that may sense cardiac electrical signals and/or determine arrhythmias but do not deliver electrical stimulation therapies).
In some examples, leads 112 are implanted on or within the heart of the patient. Leads 112 may contain one or more electrodes 114 positioned at various locations on leads 112 and distances from housing 120. Some leads 112 may only include a single electrode 114 while other leads 112 may include multiple electrodes 114. Generally, electrodes 114 are positioned on leads 112 such that when leads 112 are implanted within the patient, one or more electrodes 114 are in contact with the patient's cardiac tissue. Accordingly, electrodes 114 may conduct intrinsically generated electrical signals to leads 112. Leads 112 may, in turn, conduct the received electrical signals to one or more modules 102, 104, 106, and 108 of MD 100. In a similar manner, MD 100 may generate electrical stimulation, and leads 112 may conduct the generated electrical stimulation to electrodes 114. Electrodes 114 may then conduct the electrical signals to the cardiac tissue of the patient. When discussing sensing intrinsic signals and delivering electrical stimulation, this disclosure may consider such conduction implicit in those processes.
Sensing module 102 may be configured to sense the cardiac electrical activity of the heart. For example, sensing module 102 may be connected to leads 112 and electrodes 114 through leads 112 and sensing module 102 may be configured to receive cardiac electrical signals conducted through electrodes 114 and leads 112. In some examples, leads 112 may include various sensors, such as accelerometers, blood pressure sensors, heart sound sensors, blood-oxygen sensors, and other sensors which measure physiological parameters of the heart and/or patient. In other examples, such sensors may be connected directly to sensing module 102 rather than to leads 112. In any case, sensing module 102 may be configured to receive such signals produced by any sensors connected to sensing module 102, either directly or through leads 112. Sensing modules 102 may additionally be connected to processing module 106 and may be configured to communicate such received signals to processing module 106.
Pulse generator module 104 may be connected to electrodes 114. In some examples, pulse generator module 104 may be configured to generate an electrical stimulation signals to provide electrical stimulation therapy to the heart. For example, pulse generator module 104 may generate such a signal by using energy stored in battery 110 within MD 100. Pulse generator module 104 may be configured to generate electrical stimulation signals in order to provide one or multiple of a number of different therapies. For example, pulse generator module 104 may be configured to generate electrical stimulation signals to provide bradycardia therapy, tachycardia therapy, cardiac resynchronization therapy, and fibrillation therapy. Bradycardia therapy may include generating and delivering pacing pulses at a rate faster than the intrinsically generated electrical signals in order to try to increase the heart rate. Tachycardia therapy may include ATP therapy as described herein. Cardiac resynchronization therapy may include CRT therapy also described herein. Fibrillation therapy may include delivering a fibrillation pulse to try to override the heart and stop the fibrillation state. In other examples, pulse generator 104 may be configured to generate electrical stimulation signals to provide electrical stimulation therapies different than those described herein to treat one or more detected arrhythmias.
Processing module 106 can be configured to control the operation of MD 100. For example, processing module 106 may be configured to receive electrical signals from sensing module 102. Based on the received signals, processing module 106 may be able to determine occurrences of arrhythmias. Based on any determined arrhythmias, processing module 106 may be configured to control pulse generator module 104 to generate electrical stimulation in accordance with one or more therapies to treat the determined one or more arrhythmias. Processing module 106 may further receive information from telemetry module 108. In some examples, processing module 106 may use such received information in determining whether an arrhythmia is occurring or to take particular action in response to the information. Processing module 106 may additionally control telemetry module 108 to send information to other devices.
In some examples, processing module 106 may include a pre-programmed chip, such as a very-large-scale integration (VLSI) chip or an application specific integrated circuit (ASIC). In such embodiments, the chip may be pre-programmed with control logic in order to control the operation of MD 100. By using a pre-programmed chip, processing module 106 may use less power than other programmable circuits while able to maintain basic functionality, thereby increasing the battery life of MD 100. In other examples, processing module 106 may include a programmable microprocessor. Such a programmable microprocessor may allow a user to adjust the control logic of MD 100, thereby allowing for greater flexibility of MD 100 than when using a pre-programmed chip. In some examples, processing module 106 may further include a memory circuit and processing module 106 may store information on and read information from the memory circuit. In other examples, MD 100 may include a separate memory circuit (not shown) that is in communication with processing module 106, such that processing module 106 may read and write information to and from the separate memory circuit.
Telemetry module 108 may be configured to communicate with devices such as sensors, other medical devices, or the like, that are located externally to MD 100. Such devices may be located either external or internal to the patient's body. Irrespective of the location, external devices (i.e. external to the MD 100 but not necessarily external to the patient's body) can communicate with MD 100 via telemetry module 108 to accomplish one or more desired functions. For example, MD 100 may communicate sensed electrical signals to an external medical device through telemetry module 108. The external medical device may use the communicated electrical signals in determining occurrences of arrhythmias. MD 100 may additionally receive sensed electrical signals from the external medical device through telemetry module 108, and MD 100 may use the received sensed electrical signals in determining occurrences of arrhythmias. Telemetry module 108 may be configured to use one or more methods for communicating with external devices. For example, telemetry module 108 may communicate via radiofrequency (RF) signals, inductive coupling, optical signals, acoustic signals, conducted communication signals, or any other signals suitable for communication. Communication techniques between MD 100 and external devices will be discussed in further detail with reference to
Battery 110 may provide a power source to MD 100 for its operations. In one example, battery 110 may be a non-rechargeable lithium-based battery. In other examples, the non-rechargeable battery may be made from other suitable materials know in the art. Because, in examples where MD 100 is an implantable device, access to MD 100 may be limited, it is necessary to have sufficient capacity of the battery to deliver sufficient therapy over a period of treatment such as days, weeks, months, or years. In other examples, battery 110 may a rechargeable lithium-based battery in order to facilitate increasing the useable lifespan of MD 100.
In general, MD 100 may be similar to one of a number of existing medical devices. For example, MD 100 may be similar to various implantable medical devices. In such examples, housing 120 of MD 100 may be implanted in a transthoracic region of the patient. Housing 120 may generally include any of a number of known materials that are safe for implantation in a human body and may, when implanted, hermetically seal the various components of MD 100 from fluids and tissues of the patient's body.
In some examples, MD 100 may be an implantable cardiac pacemaker (ICP). In such an example, MD 100 may have one or more leads, for example leads 112, which are implanted on or within the patient's heart. The one or more leads 112 may include one or more electrodes 114 that are in contact with cardiac tissue and/or blood of the patient's heart. MD 100 may also be configured to sense intrinsically generated cardiac electrical signals and determine, for example, one or more cardiac arrhythmias based on analysis of the sensed signals. MD 100 may further be configured to deliver CRT, ATP therapy, bradycardia therapy, defibrillation therapy and/or other therapy types via leads 112 implanted within the heart.
In some instances, MD 100 may be a subcutaneous cardioverter-defibrillator (S-ICD). In such examples, one of leads 112 may include a subcutaneously implanted lead. In some cases, MD 100 may be configured to sense intrinsically generated cardiac electrical signals and determine one or more cardiac arrhythmias based on analysis of the sensed signals. MD 100 may further be configured to deliver one or more defibrillation pulses in response to determining an arrhythmia.
In still other examples, MD 100 may be a leadless cardiac pacemaker (LCP—described more specifically with respect to
In some instances, MD 100 may be a diagnostic-only device. In some cases, MD 100 may be configured to sense, or receive, cardiac electrical signals and/or physical parameters such as mechanical contraction, heart sounds, blood pressure, blood-oxygen levels, etc. MD 100 may further be configured to determine occurrences of arrhythmias based on the sensed or received cardiac electrical signals and/or physical parameters. In one example, MD 100 may do away with pulse generation module 104, as MD 100 may not be configured to deliver electrical stimulation in response to determining an occurrence of an arrhythmia. Rather, in order to respond to detected cardiac arrhythmias,
MD 100 may be part of a system of medical devices. In such a system, MD 100 may communicate information to other devices within the system and one or more of the other devices may take action, for example delivering electrical stimulation therapy, in response to the receive information from MD 100. The term pulse generator may be used to describe any such device that is capable of delivering electrical stimulation therapy to the heart, such as an ICD, ICP, LCP, or the like. In some instances, the MD 100 may be a neural stimulation device, or any other medical device, as desired.
In some example, MD 100 may not be an implantable medical device. Rather, MD 100 may be a device external to the patient's body, and may include skin-electrodes that are placed on a patient's body. In such examples, MD 100 may be able to sense surface cardiac electrical signals (e.g. electrical signals that are generated by the heart or device implanted within a patient's body and conducted through the body to the skin) In such examples, MD 100 may still be configured to deliver various types of electrical stimulation therapy. In other examples, however, MD 100 may be a diagnostic-only device, a neurostimulator, and/or other implantable medical devices.
In some examples, LCP 200 may include electrical sensing module 206 and mechanical sensing module 208. Electrical sensing module 206 may be similar to sensing module 102 of MD 100. For example, electrical sensing module 206 may be configured to receive electrical signals generated intrinsically by the heart. Electrical sensing module 206 may be in electrical connection with electrodes 214, which may conduct the intrinsically generated electrical signals to electrical sensing module 206. Mechanical sensing module 208 may be configured to receive one or more signals representative of one or more physiological parameters of the heart. For example, mechanical sensing module 208 may include, or be in electrical communication with one or more sensors, such as accelerometers, blood pressure sensors, heart sound sensors, blood-oxygen sensors, and other sensors which measure physiological parameters of the patient. Although described with respect to
In at least one example, each of modules 202, 204, 206, 208, and 210 illustrated in
As depicted in
To implant LCP 200 inside patient's body, an operator (e.g., a physician, clinician, etc.), may need to affix LCP 200 to the cardiac tissue of the patient's heart. To facilitate fixation, LCP 200 may include one or more anchors 216. Anchor 216 may be any one of a number of fixation or anchoring mechanisms. For example, anchor 216 may include one or more pins, staples, threads, screws, helix, tines, and/or the like. In some examples, although not shown, anchor 216 may include threads on its external surface that may run along at least a partial length of anchor 216. The threads may provide friction between the cardiac tissue and the anchor to help fix anchor 216 within the cardiac tissue. In other examples, anchor 216 may include other structures such as barbs, spikes, or the like to facilitate engagement with the surrounding cardiac tissue.
The design and dimensions of MD 100 and LCP 200, as shown in
While IMD 100 and LCP 200 are described as suitable example medical devices, it is contemplated that the present disclosure is applicable more broadly to communication between any two (or more) medical devices.
In some embodiments, each of MD 310, MD 320 and MD 330, if present, may be implanted and/or positioned proximate the patient. In some embodiments, MD 310 may be implanted, MD 320 may be external to the patient and MD 330 may be optional. MD 320 may include a skin patch including two or more electrodes. In some cases, one or more of MD 310, MD 320 and MD 330 may be a medical device programmer or communicator that is configured to communicate with and/or program one or more implanted medical device. For example, MD 320 may be a medical device programmer or communicator that is configured to communicate with and/or program one or more implanted medical device - such as MD 310 and MD 330. In some embodiments, MD 310 may be implanted within the patient and MD 320 and/or MD 330 may also be implanted within the patient but be spaced apart from MD 310 and from each other.
As illustrated, MD 310 includes a first electrode 312 and a second electrode 314. MD 320 includes a first electrode 322, a second electrode 324 and a third electrode 326. MD 330 includes a first electrode 332, a second electrode 334, a third electrode 336 and a fourth electrode 338. In this example, MD 310 has a single electrode pair 315 that can be used to sense, pace and/or communicate with another medical device. MD 320 has a first electrode pair 325 between first electrode 322 and second electrode 324, a second electrode pair 327 between second electrode 324 and third electrode 326, and a third electrode pair 329 between first electrode 322 and third electrode 326 that can each be used, either individually or in combination, to sense, pace and/or communicate with another medical device. MD 330 has a first electrode pair 333 between first electrode 332 and second electrode 334, a second electrode pair 335 between second electrode 334 and third electrode 336, a third electrode pair 337 between third electrode 336 and fourth electrode 338, a fourth electrode pair 339 between first electrode 332 and fourth electrode 338, a fifth electrode pair 331 between first electrode 332 and third electrode 336 and a sixth electrode pair 341 between second electrode 334 and fourth electrode 338 that can each be used, either individually or in combination, to sense, pace and/or communicate with another medical device.
It will be appreciated that the relative signal strength received at a particular electrode pair can be a function of, at least in part, the relative orientation of the electrode pair relative to the electromagnetic field that is being generated by a transmitting electrode pair.
In the illustration of
As illustrated, electrode pair vector A forms an angle OA that is 90 degrees. As the cosine of 90 degrees is zero, electrode pair vector A (between first electrode 510 and second electrode 520) would not receive a signal. Electrode pair vector B forms an angle AB that is 15 degrees. The cosine of 15 degrees is 0.97, and thus electrode pair vector B would receive a signal that is 97% of the strength of the signal at that location. Electrode pair vector C forms an angle Ac that is 45 degrees. The cosine of 45 degrees is 0.71, and thus electrode pair vector C would receive a signal that is 71% of the strength of the signal at that location. It will be appreciated, therefore, that by having several electrode pairs, or electrode pair vectors, to choose from may facilitate the devices MD 310, MD 320 and MD 330 of system 300 (
It can be seen that having two electrodes can provide a situation in which there can be no or substantially no signal strength at the location of a receiving antennae, depending on orientation of the receiving antennae relative to the emitted electric field. Having three electrodes provides three possible electrode pair vectors that can be selected, whereby selecting the electrode pair vector with the greatest signal strength, may help improve the signal strength received by the receiving antennae. Having four electrodes provides six possible electrode pair vectors that can be selected. In some cases, and to provide even more vectors, two or more of the electrodes may be effectively shorted together so that the shorted electrodes collectively act as an electrode. For example, and specifically with respect to
In some instances, the medical devices described herein, including MD 100, LCP 200, MD 310, MD 320, MD 330, MD 600 or MD 700 may be programmed or otherwise configured to test various communication vectors and to select the appropriate communication vector for communication. In some embodiments, the strongest communication vector may be selected. In some embodiments, the weakest communication vector may be excluded from use. In some embodiments, depending on the purpose of the communication, several communication vectors may be used in combination.
In some instances, one vector may be used during a first part of a single communication and a second vector may be used during a second part of the communication. This may occur when, for example, a device programmer or an S-ICD is communicating with a LCP. The LCP may be moving during each beat of the heart, and the angles between the various electrodes may change over time. In some cases, it may be advantageous to use a first vector to start communication, and then as the LCP moves, switch to a second vector to complete the communication.
Alternatively, or in addition, communication may be simultaneously performed using two or more vectors. This may provide one or more redundant communication paths, so that if one communication path becomes less effective or drops out, then the redundant communication path(s) can be used. For example, and specifically with respect to
In some cases, there may be a desire for communication between two or more of LCP 782, LCP 784, SICD 786 and/or an MD 700. It will be appreciated, for example, that for communication between the LCP 782 and MD 700, there may be a total of four (or more) electrodes on MD 700 and two to four (or more) electrodes on LCP 782, and thus many different communication vectors may be tested and selected as discussed previously. In some cases, particularly in conducting communication between SICD 786 and any of the other devices shown, it will be appreciated that electrodes 792, 794 and 796 are arranged in a largely linear fashion near a distal end of lead 790. Accordingly, in some cases, selecting between these three electrodes for use in a communication vector with an LCP 872 or 784 may not substantially change the geometry of the vector and thus may not substantially improve the communication vector. In some embodiments, communication with SICD 786 may benefit from also considering one or more can electrodes, such as can electrode 797 of the SICD 786. When so provided, the SICD may have four different electrodes 792, 794, 796 and 797, and each LCP 782 and 784 may have two to four (or more) electrodes. This may provide many vectors to choose from with a variety of different vector geometries. Alternatively, or in addition, the SICD electrodes 792, 794 and 796 may be arranged in a non-linear manner, such as in a cross-pattern.
One or all of the electrodes 792, 794, 796, 797 and the SCID 786 housing may be used only for communication; alternatively one or all of the electrodes 792, 794, 796, 797 and the SCID 786 housing may also be used for other purposes such as sensing a physiological parameter (e.g. intrinsic cardiac activity, thoracic impedance) and/or delivering one or more electrical therapies (e.g. cardioversion/defibrillation shocks, cardiac paces, neural stimulation energy).
In some cases, it will be appreciated that which specific vector or vectors are most useful for communicating between any particular pair of devices may change over time. For example, LCP 782 and/or LCP 784, if present, may move and change orientation somewhat with each heartbeat. As the patient breathes, and their chest rises and falls, the SICD 786 and an external device such as MD 700 may also move. Accordingly, in some embodiments, it may be advantageous to use a first vector for part of a communication, and then as one or more devices move relative to one another, such as with the heartbeat and/or patient respiration, switch to a second vector to continue the communication. In some cases, signal strength, error rate and/or communication parameter may be monitored over time, and the vector may be automatically switched if desired. While a first and second vector are used here an example, it is contemplated that the system may switch between more than two different vectors if desired. It is contemplated that the vectors may be switched in real or near real time, and/or may be updated from time to time, e.g. every minute, hour, day, month, each doctor visit, and/or any other suitable time.
MD 310, MD 320, MD 330, MD 600 or MD 700. At block 1010, a first electrode pair of an antenna having at least three electrodes is selected. A communication signal, such as a conducted communication signal, may be sent through tissue of the patient between the first electrode pair of the antenna having at least three electrodes and two electrodes of another antenna, as generally seen at block 1020. At block 1030, a second electrode pair of the antenna having at least three electrodes is selected. The second electrode pair selected being different from the first selected electrode pair. A communication signal is again sent through tissue of the patient between the first electrode pair of the antenna having at least three electrodes and two electrodes of another antenna, as generally seen at block 1040.
During operation, and as seen at block 1150, a measure related to a signal-to-noise ratio of the conducted communication signal using the first electrode pair may be monitored. If the measure related to the signal-to-noise ratio falls below a threshold or changes by more than a threshold, the second electrode pair of the antenna having at least three electrodes is selected, as generally shown at block 1160. At block 1170, a communication signal may then be sent through tissue of the patient between the second electrode pair of the antenna having at least three electrodes and the two electrodes of the other antenna.
MD 310, MD 320, MD 330, MD 600 or MD 700. At block 1210, a first electrode pair of an antenna having at least three electrodes is selected. A communication signal is sent through tissue of the patient between the first electrode pair of the antenna having at least three electrodes and two electrodes of another antenna, as generally seen at block 1220. At block 1230, a second electrode pair of the antenna that has at least three electrodes is selected. The second electrode pair is different from the first selected electrode pair. A communication signal is sent through tissue of the patient between the first electrode pair of the antenna having at least three electrodes and two electrodes of another antenna, as generally seen at block 1240.
During operation, and as block 1280, a first measure related to a signal-to-noise ratio of the communication signal using the first electrode pair is determined. A second measure related to a signal-to-noise ratio of the communication signal using the second electrode pair is determined, as generally indicated at block 1290. At block 1292, the first electrode pair or the second electrode pair is selected for subsequent communication based on the first measure and the second measure.
As detailed above, the medical devices referenced herein may by any suitable medical device. In some non-limiting example, the methods 1000, 1100, 1200, 1300 may be used in communication between an LCP and a medical device programmer or communicator, an LCP and an Sub-coetaneous Implantable Cardioverter Defibrillator (SICD), an LCP and a co-implanted diagnostic device, an LCP and a neurostimulator device, an LCP and another LCP, and/or between any other suitable medical devices, as desired.
In some embodiments, any of these methods described herein could embody receiving a communication instead or, or in addition to, sending a communication signal. In some embodiments, a selection or determination of a communication vector used for sending a communication signal may be the same as a communication vector used for receiving a communication signal. In some embodiments, a selection or determination of a communication vector used for sending a communication signal may be different than a communication vector used for receiving a communication signal.
Those skilled in the art will recognize that the present disclosure may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. As one example, as described herein, various examples include one or more modules described as performing various functions. However, other examples may include additional modules that split the described functions up over more modules than that described herein. Additionally, other examples may consolidate the described functions into fewer modules. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present disclosure as described in the appended claims.
Claims
1. A method of communicating between a first medical device having a first antenna and a second medical device having a second antenna, wherein the first medical device is implanted within a patient and the second medical device is proximate to the patient, and wherein the first antenna and/or the second antenna has at least three electrodes and the other antenna has at least two electrodes, the method comprising:
- selecting a first electrode pair of the antenna that has at least three electrodes;
- at least one of sending and receiving a conducted communication signal through tissue of the patient between the first electrode pair of the antenna that has at least three electrodes and two of the electrodes of the other antenna;
- selecting a second electrode pair of the antenna that has at least three electrodes, wherein the second electrode pair is different from the first electrode pair; and
- sending a conducted communication signal through tissue of the patient between the second electrode pair of the antenna that has at least three electrodes and two electrodes of the other antenna.
2. The method of claim 1, further comprising:
- monitoring a measure related to a signal to noise ratio of the conducted communication signal using the first electrode pair;
- if the measure related to a signal to noise ratio of the conducted communication signal using the first electrode pair falls below a threshold, then: selecting the second electrode pair of the antenna that has at least three electrodes; and sending the conducted communication signal through tissue of the patient between the second electrode pair of the antenna that has at least three electrodes and the two electrodes of the other antenna.
3. The method of claim 1, further comprising:
- determining a first measure related to a signal to noise ratio of the conducted communication signal using the first electrode pair;
- determining a second measure related to a signal to noise ratio of the conducted communication signal using the second electrode pair; and
- selecting the first electrode pair or the second electrode pair for subsequent communication based on the first measure and the second measure.
4. The method of claim 1, wherein the second medical device is implanted within the patient but spaced from the first medical device.
5. The method of claim 1, wherein the second medical device is disposed outside of the patient and the second antenna is positioned on a skin surface of the patient.
6. The method of claim 1, wherein the antenna that has at least three electrodes comprises three electrodes that are arranged in a triangular configuration.
7. The method of claim 1, wherein the antenna that has at least three electrodes comprises four electrodes that are arranged in a rectangular configuration.
8. The method of claim 1, wherein the antenna that has at least three electrodes comprises four electrodes that are arranged in a kite configuration.
9. A method of communicating between a first medical device having a first antenna with at least two electrodes and a second medical device having a second antenna with at least three electrodes, the method comprising:
- testing communication vectors between the at least two electrodes of the first antenna and each of a plurality of pairs of electrodes of the at least three electrodes of the second antenna;
- selecting a communication vector based on signal strengths of each of the communication vectors; and
- at least one of sending and receiving a conducted communication between the first medical device and the second medical device using the selected communication vector.
10. The method of claim 9, wherein the first medical device comprises an implanted medical device and the second medical device comprises an external device.
11. The method of claim 9, wherein the first medical device comprises an external device and the second medical device comprises an implanted medical device.
12. The method of claim 9, wherein the first medical device comprises a first implanted medical device and the second medical device comprises a second implanted medical device.
13. The method of claim 9, wherein selecting a communication vector comprises selecting the communication vector with the strongest signal strength.
14. The method of claim 9, wherein selecting a communication vector comprises not selecting the communication vector with the weakest signal strength.
15. A communication system, comprising:
- a first medical device in communication with a first antenna having at least two electrodes; and
- a second medical device in communication with a second antenna having at least three electrodes;
- wherein at least one of the first medical device and the second medical device is configured to: test communication vectors between the at least two electrodes of the first antenna and at least two pairs of the at least three electrodes of the second antenna; select a communication vector from the tested communication vectors; and at least one of send and receive a conducted communication along the selected communication vector.
16. The communication system of claim 15, wherein the at least three electrodes comprise three electrodes that are arranged in a triangular configuration.
17. The communication system of claim 15, wherein the at least three electrodes comprise four electrodes that are arranged in a rectangular configuration.
18. The communication system of claim 15, wherein the at least three electrodes comprise four electrodes that are arranged in a kite configuration.
19. The communication system of claim 15, wherein at least one of the first medical device and the second medical device are implanted within a patient.
20. The communication system of claim 15, wherein the first medical device is a leadless cardiac pacemaker (LCP).
Type: Application
Filed: Jan 8, 2015
Publication Date: Jul 16, 2015
Inventors: Jeffrey E. Stahmann (Ramsey, MN), William J. Linder (Golden Valley, MN), Keith R. Maile (New Brighton, MN)
Application Number: 14/592,595