Systems and methods for detecting cardiac arrhythmias

Systems and methods for coordinating detection and/or treatment of abnormal heart activity using multiple implanted devices within a patient. In one example, cardiac activity may be sensed by two or more medical device, including a leadless cardiac pacemaker. Cardiac activity sensed by one of the implanted devices may be communicated to another one of the implanted devices. Abnormal heart activity may then be determined based on the cardiac activity of both of the medical device.

TECHNICAL FIELD

The present disclosure generally relates to systems, devices, and methods for detecting cardiac arrhythmias, and more specifically to multiple device systems, methods, and devices for detecting and identifying cardiac arrhythmias.

BACKGROUND

Pacing 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 implanted devices.

SUMMARY

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. It is contemplated that the multiple implanted devices may include, for example, pacemakers, defibrillators, diagnostic devices, and/or any other suitable implantable devices, as desired.

In one example, a leadless cardiac pacemaker (LCP) may be implanted to aid in determining and/or treating a tachyarrhythmia. Cardiac activity of the heart can be sensed using one or more leadless cardiac pacemakers (LCPs) either alone or in combination with one or more other devices. The leadless cardiac pacemakers (LCPs) can be implanted in close proximity to the heart, such as in or on the heart. In some instances, sensing cardiac activity by the one or more leadless cardiac pacemakers (LCPs) can help the system determine an occurrence of cardiac arrhythmia. For treatment purposes, electrical stimulation therapy, for example anti-tachyarrhythmia pacing (ATP) therapy, may be delivered by at least one of the implanted devices. Such therapy can help treat the detected cardiac arrhythmia.

An illustrative method of identifying a tachyarrhythmia of a heart may include: sensing cardiac activity by a medical device, sensing cardiac activity by a first leadless cardiac pacemaker, wherein the first leadless cardiac pacemaker is spaced from the medical device and communicatively coupled to the medical device via a communication pathway that includes the body of the patient, and determining if a tachyarrhythmia is occurring based, at least in part, on both the cardiac activity sensed by the medical device and the cardiac activity sensed by the first leadless cardiac pacemaker.

Another illustrative method of identifying a tachyarrhythmia of a heart of a patient may include: sensing cardiac activity by a medical device; sensing cardiac activity by a first leadless cardiac pacemaker, wherein the first leadless cardiac pacemaker is communicatively coupled to the medical device via a communication pathway that includes the body of the patient; determining, by one or more of the medical device and the first leadless cardiac pacemaker, if a tachyarrhythmia is occurring based, at least in part, on the cardiac activity sensed by the medical device and/or the cardiac activity sensed by the first leadless cardiac pacemaker; and after determining a tachyarrhythmia is occurring, determining, by one or more of the medical device and the first leadless cardiac pacemaker, a type of the tachyarrhythmia based, at least in part, on both the cardiac activity sensed by the medical device and the cardiac activity sensed by the first leadless cardiac pacemaker.

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.

DESCRIPTION

The 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 this 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 abnormalities. 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).

FIG. 1illustrates a block diagram of an exemplary medical device100(referred to hereinafter as, MD100) that may be used in accordance with various examples of the present disclosure. In some cases, the MD100may be used for sensing intrinsic cardiac activity, determining occurrences of arrhythmias, and delivering electrical stimulation in response to determining an occurrence of an arrhythmia. In some instances, MD100can be implanted within a patient's body, at a particular location (e.g., in close proximity to the patient's heart), to sense and/or regulate the cardiac activity of the heart. In other examples, MD100may be located externally to a patient to sense and/or regulate the cardiac activity of the heart. In one example, cardiac contractions generally result from electrical signals that are intrinsically generated by a heart. These electrical signals conduct through the heart tissue, causing the muscle cells of the heart to contract. MD100may include features that allow MD100to sense such electrical signals and/or other physical parameters (e.g. mechanical contraction, heart sounds, blood pressure, blood-oxygen levels, etc.) of the heart. Such electrical signals and/or physical properties may be considered “cardiac activity.” MD100may include the ability to determine occurrences of arrhythmias based on the sensed cardiac activity. In some examples, MD100may be able to deliver electrical stimulation to the heart in order to treat any detected arrhythmias. For example, MD100may be configured to deliver electrical stimulation, pacing pulses, defibrillation pulses, and/or the like in order to implement one or more therapies, such as bradycardia therapy, ATP therapy, CRT, defibrillation, or other electrical stimulation therapies.

FIG. 1is an illustration of one example medical device100. The illustrative MD100may include a sensing module102, a pulse generator module104, a processing module106, a telemetry module108, and a battery110, all housed within a housing120. MD100may further include leads112, and electrodes114attached to housing120and in electrical communication with one or more of the modules102,104,106, and108housed within housing120.

Leads112may be connected to and extend away from housing120of MD100. In some examples, leads112are implanted on or within the heart of the patient, such as heart115. Leads112may contain one or more electrodes114positioned at various locations on leads112and distances from housing120. Some leads112may only include a single electrode114while other leads112may include multiple electrodes114. Generally, electrodes114are positioned on leads112such that when leads112are implanted within the patient, one or more electrodes114are in contact with the patient's cardiac tissue. Accordingly, electrodes114may conduct intrinsically generated electrical signals to leads112. Leads112may, in turn, conduct the received electrical signals to one or more modules102,104,106, and108of MD100. In a similar manner, MD100may generate electrical stimulation, and leads112may conduct the generated electrical stimulation to electrodes114. Electrodes114may 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 module102may be configured to sense the cardiac electrical activity of the heart. For example, sensing module102may be connected to leads112and electrodes114through leads112and sensing module102may be configured to receive cardiac electrical signals conducted through electrodes114and leads112. In some examples, leads112may 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 module102rather than to leads112. In any case, sensing module102may be configured to receive such signals produced by any sensors connected to sensing module102, either directly or through leads112. Sensing modules102may additionally be connected to processing module106and may be configured to communicate such received signals to processing module106.

Pulse generator module104may be connected to electrodes114. In some examples, pulse generator module104may be configured to generate an electrical stimulation signals to provide electrical stimulation therapy to the heart. For example, pulse generator module104may generate such a signal by using energy stored in battery110within MD100. Pulse generator module104may be configured to generate electrical stimulation signals in order to provide one or multiple of a number of different therapies. For example, pulse generator module104may 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 generator104may 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 module106can be configured to control the operation of MD100. For example, processing module106may be configured to receive electrical signals from sensing module102. Based on the received signals, processing module106may be able to determine occurrences of arrhythmias. Based on any determined arrhythmias, processing module106may be configured to control pulse generator module104to generate electrical stimulation in accordance with one or more therapies to treat the determined one or more arrhythmias. Processing module106may further receive information from telemetry module108. In some examples, processing module106may use such received information in determining whether an arrhythmia is occurring or to take particular action in response to the information. Processing module106may additionally control telemetry module108to send information to other devices.

In some examples, processing module106may 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 MD100. By using a pre-programmed chip, processing module106may use less power than other programmable circuits while able to maintain basic functionality, thereby increasing the battery life of MD100. In other examples, processing module106may include a programmable microprocessor. Such a programmable microprocessor may allow a user to adjust the control logic of MD100, thereby allowing for greater flexibility of MD100than when using a pre-programmed chip. In some examples, processing module106may further include a memory circuit and processing module106may store information on and read information from the memory circuit. In other examples, MD100may include a separate memory circuit (not shown) that is in communication with processing module106, such that processing module106may read and write information to and from the separate memory circuit.

Telemetry module108may be configured to communicate with devices such as sensors, other medical devices, or the like, that are located externally to MD100. 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 MD100but not necessarily external to the patient's body) can communicate with MD100via telemetry module108to accomplish one or more desired functions. For example, MD100may communicate sensed electrical signals to an external medical device through telemetry module108. The external medical device may use the communicated electrical signals in determining occurrences of arrhythmias. MD100may additionally receive sensed electrical signals from the external medical device through telemetry module108, and MD100may use the received sensed electrical signals in determining occurrences of arrhythmias. Telemetry module108may be configured to use one or more methods for communicating with external devices. For example, telemetry module108may communicate via radiofrequency (RF) signals, inductive coupling, optical signals, acoustic signals, conducted communication signals, or any other signals suitable for communication. Communication techniques between MD100and external devices will be discussed in further detail with reference toFIG. 3below.

Battery110may provide a power source to MD100for its operations. In one example, battery110may be a non-rechargeable lithium-based battery. In other examples, the non-rechargeable battery may be made from other suitable materials known in the art. Because, in examples where MD100is an implantable device, access to MD100may 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, battery110may a rechargeable lithium-based battery in order to facilitate increasing the useable lifespan of MD100.

In general, MD100may be similar to one of a number of existing medical devices. For example, MD100may be similar to various implantable medical devices. In such examples, housing120of MD100may be implanted in a transthoracic region of the patient. Housing120may 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 MD100from fluids and tissues of the patient's body.

In some examples, MD100may be an implantable cardiac pacemaker (ICP). In such an example, MD100may have one or more leads, for example leads112, which are implanted on or within the patient's heart. The one or more leads112may include one or more electrodes114that are in contact with cardiac tissue and/or blood of the patient's heart. MD100may 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. MD100may further be configured to deliver CRT, ATP therapy, bradycardia therapy, defibrillation therapy and/or other therapy types via leads112implanted within the heart.

In some instances, MD100may be a subcutaneous cardioverter-defibrillator (S-ICD). In such examples, one of leads112may include a subcutaneously implanted lead. In some cases, MD100may be configured to sense intrinsically generated cardiac electrical signals and determine one or more cardiac arrhythmias based on analysis of the sensed signals. MD100may further be configured to deliver one or more defibrillation pulses in response to determining an arrhythmia. In other examples, MD100may be an implantable cardioverter-defibrillator (ICD), where one or more of leads112may be implanted within heart115.

In still other examples, MD100may be a leadless cardiac pacemaker (LCP—described more specifically with respect toFIG. 2). In such examples, MD100may not include leads112that extend away from housing120. Rather, MD100may include electrodes114coupled relative to the housing120. In these examples, MD100may be implanted on or within the patient's heart at a desired location, and may be configured to deliver CRT, ATP therapy, bradycardia therapy, and/or other therapy types via electrodes114.

In some instances, MD100may be a diagnostic-only device. In some cases, MD100may 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. MD100may further be configured to determine occurrences of arrhythmias based on the sensed or received cardiac electrical signals and/or physical parameters. In one example, MD100may do away with pulse generation module104, as MD100may 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, MD100may be part of a system of medical devices. In such a system, MD100may 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 MD100. 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 examples, MD100may not be an implantable medical device. Rather, MD100may 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, MD100may 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, MD100may still be configured to deliver various types of electrical stimulation therapy. In other examples, however, MD100may be a diagnostic-only device.

FIG. 2is an illustration of an exemplary leadless cardiac pacemaker (LCP)200. In the example shown, LCP200may include all of the modules and components of MD100, except that LCP200may not include leads112. As can be seen inFIG. 2, LCP200may be a compact device with all components housed within LCP200or directly on housing220. As illustrated inFIG. 2, LCP200may include telemetry module202, pulse generator module204, processing module210, and battery212. Such components may have a similar function to the similarly named modules and components as discussed in conjunction with MD100ofFIG. 1.

In some examples, LCP200may include electrical sensing module206and mechanical sensing module208. Electrical sensing module206may be similar to sensing module102of MD100. For example, electrical sensing module206may be configured to receive electrical signals generated intrinsically by the heart. Electrical sensing module206may be in electrical connection with electrodes214, which may conduct the intrinsically generated electrical signals to electrical sensing module206. Mechanical sensing module208may be configured to receive one or more signals representative of one or more physiological parameters of the heart. For example, mechanical sensing module208may 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 toFIG. 2as separate sensing modules, in some examples, electrical sensing module206and mechanical sensing module208may be combined into a single module.

In at least one example, each of modules202,204,206,208, and210illustrated inFIG. 2may be implemented on a single integrated circuit chip. In other examples, the illustrated components may be implemented in multiple integrated circuit chips that are in electrical communication with one another. All of modules202,204,206,208, and210and battery212may be encompassed within housing220. Housing220may generally include any material that is known as safe for implantation within a human body and may hermetically seal modules202,204,206,208, and210and battery212from fluids and tissues when LCP200is implanted within a patient.

As depicted inFIG. 2, LCP200may include electrodes214, which can be secured relative to housing220but exposed to the tissue and/or blood surrounding the LCP200. As such, electrodes214may be generally disposed on either end of LCP200and may be in electrical communication with one or more of modules202,204,206,208, and210. In some examples, electrodes214may be connected to housing220only through short connecting wires such that electrodes214are not directly secured relative to housing220. In some examples, LCP200may additionally include one or more electrodes214′. Electrodes214′ may be positioned on the sides of LCP200and increase the number of electrodes by which LCP200may sense cardiac electrical activity and/or deliver electrical stimulation. Electrodes214and/or214′ can be made up of one or more biocompatible conductive materials such as various metals or alloys that are known to be safe for implantation within a human body. In some instances, electrodes214and/or214′ connected to LCP200may have an insulative portion that electrically isolates the electrodes214from, adjacent electrodes, the housing220, and/or other materials.

To implant LCP200inside patient's body, an operator (e.g., a physician, clinician, etc.), may need to fix LCP200to the cardiac tissue of the patient's heart. To facilitate fixation, LCP200may include one or more anchors216. Anchor216may be any one of a number of fixation or anchoring mechanisms. For example, anchor216may include one or more pins, staples, threads, screws, helix, tines, and/or the like. In some examples, although not shown, anchor216may include threads on its external surface that may run along at least a partial length of anchor216. The threads may provide friction between the cardiac tissue and the anchor to help fix anchor216within the cardiac tissue. In other examples, anchor216may include other structures such as barbs, spikes, or the like to facilitate engagement with the surrounding cardiac tissue.

The design and dimensions of MD100and LCP200, as shown inFIGS. 1 and 2, respectively, can be selected based on various factors. For example, if the medical device is for implant on the endocardial tissue, such as is sometimes the case of an LCP, the medical device can be introduced through a femoral vein into the heart. In such instances, the dimensions of the medical device may be such as to be navigated smoothly through the tortuous path of the vein without causing any damage to surrounding tissue of the vein. According to one example, the average diameter of the femoral vein may be between about 4 mm to about 8 mm in width. For navigation to the heart through the femoral vein, the medical device can have a diameter of at less than 8 mm. In some examples, the medical device can have a cylindrical shape having a circular cross-section. However, it should be noted that the medical device can be made of any other suitable shape such as rectangular, oval, etc. A flat, rectangular-shaped medical device with a low profile may be desired when the medical device is designed to be implanted subcutaneously.

FIGS. 1 and 2above described various examples of MD100. In some examples, a medical device system may include more than one medical device. For example, multiple medical devices100/200may be used cooperatively to detect and treat cardiac arrhythmias and/or other cardiac abnormalities. Some example systems will be described below in connection withFIGS. 3-10. In such multiple device systems, it may be desirable to have a medical device communicate with another medical device, or at least receive various communication signals from another medical device.

FIG. 3illustrates an example of a medical device system and a communication pathway via which multiple medical devices may communicate. In the example shown, medical device system300may include LCPs302and304, external medical device306, and other sensors/devices310. External device306may be any of the devices described previously with respect to MD100. Other sensors/devices310may also be any of the devices described previously with respect to MD100. In other examples, other sensors/devices310may include a sensor, such as an accelerometer or blood pressure sensor, or the like. In still other examples, other sensors/devices310may include an external programmer device that may be used to program one or more devices of system300.

Various devices of system300may communicate via communication pathway308. For example, LCPs302and/or304may sense intrinsic cardiac electrical signals and may communicate such signals to one or more other devices302/304,306, and310of system300via communication pathway308. In one example, external device306may receive such signals and, based on the received signals, determine an occurrence of an arrhythmia. In some cases, external device306may communicate such determinations to one or more other devices302/304,306, and310of system300. Additionally, one or more other devices302/304,306, and310of system300may take action based on the communicated determination of an arrhythmia, such as by delivering a suitable electrical stimulation. This description is just one of many reasons for communication between the various devices of system300.

Communication pathway308may represent one or more of various communication methods. For example, the devices of system300may communicate with each other via RF signals, inductive coupling, optical signals, acoustic signals, or any other signals suitable for communication and communication pathway308may represent such signals.

In at least one example, communicated pathway308may represent conducted communication signals. Accordingly, devices of system300may have components that allow for conducted communication. In examples where communication pathway308includes conducted communication signals, devices of system300may communicate with each other by sensing electrical communication pulses delivered into the patient's body by another device. The patient's body may conduct these electrical communication pulses to the other devices of system300. In such examples, the delivered electrical communication pulses may differ from the electrical stimulation pulses of any of the above described electrical stimulation therapies. For example, the devices of system300may deliver such electrical communication pulses at a voltage level that is sub-threshold. That is, the voltage amplitude of the delivered electrical communication pulses may be low enough as to not capture the heart (e.g. not cause a contraction). Although, in some circumstances, one or more delivered electrical communication pulses may capture the heart, and in other circumstances, delivered electrical stimulation pulses may not capture the heart. In some cases, the delivered electrical communication pulses may be modulated (e.g. pulse width modulated), or the timing of the delivery of the communication pulses may be modulates, to encode the communicated information. These are just some examples.

As mentioned above, some example systems may employ multiple devices for determining occurrences of arrhythmias, and/or for delivering electrical stimulation therapy in response to determining one or more arrhythmias.FIGS. 3-10describe various example systems that may use multiple devices in order to determine occurrences of arrhythmias and/or deliver electrical stimulation therapy. However,FIGS. 3-10should not be viewed as limiting examples. For example,FIGS. 3-10describe how various multiple device systems may coordinate to detect various arrhythmias. However, any combinations of devices such as that described with respect to MD100and LCP200may used in concert with the below described techniques for detecting arrhythmias. Additionally, although the below description focuses on how devices of various systems may operate to detect arrhythmias, such devices may additionally operate to deliver electrical stimulation therapy in accordance with one or more techniques, such as described in the co-pending and co-owned provisional applications titled “SYSTEMS AND METHODS FOR TREATING CARDIAC ARRHYTHMIAS”, filed on Jan. 10, 2014, and “COMMUNICATION OF THERAPY ACTIVITY OF A FIRST IMPLANTABLE MEDICAL DEVICE TO ANOTHER IMPLANTABLE MEDICAL DEVICE”, filed on Jan. 10, 2014, both of which are hereby incorporated by reference in their entirety.

FIG. 4illustrates an example medical device system400that includes an LCP402and a pulse generator406. In some examples, pulse generator406may be either an external cardioverter-defibrillator or an ICD. For example, pulse generator406may be such devices as described previously with respect to MD100. In some examples, pulse generator406may be an S-ICD. In examples where pulse generator406is an external cardioverter-defibrillator, electrodes408a,408b, and408cmay be skin electrodes that reside on the patient's body. In examples where pulse generator406is an S-ICD, electrodes408a,408b, and408cmay be attached to a subcutaneous lead that is implanted within the patient's body proximate, but not on or within the heart410.

As shown, LCP402may be implanted within heart410. Although LCP402is depicted as being implanted within the left ventricle (LV) of heart410, in other examples, LCP402may be implanted within a different chamber of the heart410. For example, LCP402may be implanted within the left atrium (LA) of heart410or the right atrium (RA) of heart410. In other examples, LCP402may be implanted within the right ventricle (RV) of heart410.

In any event, LCP402and pulse generator406may operate together to determine occurrences of cardiac arrhythmias of heart410. In some instances, devices402and406may operate independently to sense cardiac activity of heart410. As described above, cardiac activity may include sensed cardiac electrical signals and/or sensed physiological parameters. In such examples, each of LCP402and pulse generator406may operate to determine occurrences of arrhythmias independently of one another based on the independently sensed cardiac activity. When a first of LCP402or pulse generator406makes a first determination of an arrhythmia, that first device may communicate the first determination to the second device. If the second device of system400also makes a determination of an arrhythmia, e.g. a second determination of an arrhythmia, based on its own sensed cardiac activity, the arrhythmia may be confirmed and the system400may begin to deliver appropriate electrical stimulation therapy to heart410. In this manner, both devices402and406of system400may be used to determine an occurrence of an arrhythmia. In some examples, when only one of devices402or406determines an occurrence of an arrhythmia, and the other does not, system400may still begin to deliver appropriate electrical stimulation therapy to heart410.

In other examples, only one of devices402and406actively senses cardiac activity and determines occurrences of arrhythmias. For example, when the actively sensing device (e.g. LCP402) determines an occurrence of an arrhythmia, the actively sensing device may communicate the determination to the other device (e.g. Pulse Generator406) of system400. System400may then begin to deliver appropriate electrical stimulation therapy to heart410. In another example, the device which actively senses cardiac activity may communicate the sensed cardiac activity to the other device. Then, based on the received cardiac activity, the other device may determine an occurrence of an arrhythmia. System400may then begin to deliver appropriate electrical stimulation therapy to heart410. In some of these examples, the other device may additionally communicate the determination of an arrhythmia to the actively sensing device.

In still other examples, only a first of devices402or406continuously senses cardiac actively. The first device (e.g. Pulse Generator406) may continually determine, based on the sensed cardiac activity, occurrences of arrhythmias. In such examples, when the first device determines an occurrence of an arrhythmia, the first device may communicate the determination to the second device (e.g. LCP402). Upon receiving a determination of an occurrence of an arrhythmia, the second device may begin to sense cardiac activity. Based on its sensed cardiac activity, the second device may also determine an occurrence of an arrhythmia. In such examples, only after the second device also determines an occurrence of an arrhythmia, system400may begin to deliver appropriate electrical stimulation therapy to heart410.

In some examples, determining an occurrence of an arrhythmia may include determining a beginning of an arrhythmia, and system400may be configured to determine when to begin to deliver electrical stimulation therapy. In some examples, determining an occurrence of an arrhythmia may include determining an end of an arrhythmia. In such examples, system400may be configured to also determine when to cease to deliver electrical stimulation therapy.

In examples where system400operates to deliver appropriate electrical stimulation therapy to heart410, if the determined arrhythmia is a fibrillation, pulse generator406may operate to deliver a defibrillation pulse to heart410. In examples where the determined arrhythmia is a tachycardia, LCP402may deliver ATP therapy to heart410. In examples where the determined arrhythmia is a bradycardia, LCP402may deliver bradycardia therapy to heart410. In examples where the determined arrhythmia is un-synchronized contractions, LCP402may deliver CRT to heart410.

FIG. 5illustrates an example medical device system500that includes an LCP502and a pulse generator506. In this example, pulse generator506may be an implantable cardiac pacemaker (ICP). For example, pulse generator506may be an ICP such as that described previously with respect to MD100. In examples where pulse generator506is an ICP, electrodes504a,504b, and504cmay be implanted on or within the right ventricle and/or right atrium of heart510via one or more leads.

LCP502may be implanted within heart510. Although LCP502is depicted implanted within the left ventricle (LV) of the heart510, in some instances, LCP502may be implanted within a different chamber of the heart510. For example, LCP502may be implanted within the left atrium (LA) of heart510or the right atrium (RA) of heart510. In other examples, LCP502may be implanted within the right ventricle (RV) of heart510.

In any event, LCP502and pulse generator506may operate together to determine occurrences of cardiac arrhythmias of heart510. In some instances, devices502and506may operate independently to sense cardiac activity of heart510. As described above, cardiac activity may include sensed cardiac electrical signals and/or sensed physiological parameters. In some cases, each of LCP502and pulse generator506may operate to determine occurrences of arrhythmias independently based on the independently sensed cardiac activity. When a first of LCP502or pulse generator506makes a first determination of an arrhythmia, that first device may communicate the first determination to the second device. If the second device of system500also makes a determination of an arrhythmia, e.g. a second determination of an arrhythmia, based on its own sensed cardiac activity, system500may confirm the arrhythmia and may begin to deliver appropriate electrical stimulation therapy to heart510. In this manner, both devices502and506of system500may be used to determine an occurrence of an arrhythmia. In some instances, when only a single one of devices502or506determines an occurrence of an arrhythmia, system500may also begin to deliver appropriate electrical stimulation therapy to heart510.

In some examples, only one of devices502and506may actively sense cardiac activity and determine occurrences of arrhythmias. For example, when the actively sensing device (e.g. pulse generator506) determines an occurrence of an arrhythmia, the actively sensing device may communicate the determination to the other device (e.g. LCP502) of system500. System500may then begin to deliver appropriate electrical stimulation therapy to heart510. In some examples, the device which actively senses cardiac activity may communicate the sensed cardiac activity to the other device. Then, based on the received cardiac activity, the other device may sense for and determine an occurrence of an arrhythmia. System500may then begin to deliver appropriate electrical stimulation therapy to heart510. In some instances, the other device may additionally communicate the determination of an arrhythmia to the actively sensing device.

In still other examples, only a first of devices502or506may continuously sense cardiac actively. The first device may additionally continually determine, based on the sensed cardiac activity, occurrences of arrhythmias. In some examples, when the first device determines an occurrence of an arrhythmia, the first device may communicate the determination to the second device. Upon receiving a determination of an occurrence of an arrhythmia, the second device may begin to sense cardiac activity. Based on its sensed cardiac activity, the second device may also determine an occurrence of an arrhythmia. In such examples, only after the second device also determines an occurrence of an arrhythmia, system500may begin to deliver appropriate electrical stimulation therapy to heart510.

In some examples, determining an occurrence of an arrhythmia may include determining a beginning of an arrhythmia, and system500may be configured to determine when to begin to deliver electrical stimulation therapy. In some examples, determining an occurrence of an arrhythmia may include determining an end of an arrhythmia. In such examples, system500may be configured to determine when to cease to deliver electrical stimulation therapy. In examples where system500does not begin to deliver appropriate electrical stimulation therapy to heart510until multiple devices determine an occurrence of a cardiac arrhythmia, each of the determinations that do not trigger delivery of electrical stimulation therapy may be termed provisional determinations.

In examples where system500operates to deliver appropriate electrical stimulation therapy to heart510, if the determined arrhythmia is a tachycardia, either pulse generator506, LCP502, or both may deliver ATP therapy to heart510. In examples where the determined arrhythmia is a bradycardia, either pulse generator506, LCP502, or both may deliver bradycardia therapy to heart510. In examples where the determined arrhythmia is un-synchronized contractions, either pulse generator506, LCP502, or both may deliver CRT to heart510.

FIG. 6illustrates an example medical device system600that includes LCP602and LCP606. LCP602and LCP606are shown implanted within heart610. Although LCPs602and606are depicted as implanted within the left ventricle (LV) of heart610and the right ventricle of heart610, respectively, in other examples, LCPs602and606may be implanted within different chambers of heart610. For example, system600may include LCPs602and606implanted within both atria of heart610. In other examples, system600may include LCPs602and606implanted within one atrium and one ventricle of heart610. In more examples, system600may include LCPs602and606implanted within any combination of ventricles and atria. In yet other examples, system600may include LCPs602and606implanted within the same chamber of heart610.

In any event, and in some examples, LCP602and LCP606may operate together to determine occurrences of cardiac arrhythmias of heart610. For example, devices602and606may operate independently to sense cardiac activity of heart610. As described above, cardiac activity may include sensed cardiac electrical signals and/or sensed physiological parameters. In such examples, each of LCP602and LCP606may operate to determine occurrences of arrhythmias independently based on the independently sensed cardiac activity. When a first of LCP602or LCP606makes a first determination of an arrhythmia, that first device may communicate the first determination to the second device. If the second device of system600also makes a determination of an arrhythmia, e.g. a second determination of an arrhythmia, based on its own sensed cardiac activity, system600may confirm the arrhythmia and may begin to deliver appropriate electrical stimulation therapy to heart610. In this manner, both devices602and606of system600may be used to determine an occurrence of an arrhythmia. In some examples, when only a single one of devices602or606determines an occurrence of an arrhythmia, system600may begin to deliver appropriate electrical stimulation therapy to heart610.

In other examples, only one of devices602and606may actively sense cardiac activity and determine occurrences of arrhythmias. In some of these examples, when the actively sensing device (e.g. LCP606) determines an occurrence of an arrhythmia, the actively sensing device may communicate the determination to the other device (e.g. LCP602) of system600. System600may then begin to deliver appropriate electrical stimulation therapy to heart610. In some cases, the device which actively senses cardiac activity may communicate the sensed cardiac activity to the other device. Then, based on the received cardiac activity, the other device may determine an occurrence of an arrhythmia. System600may then begin to deliver appropriate electrical stimulation therapy to heart610. In some of these examples, the other device may additionally communicate the determination of an arrhythmia to the actively sensing device and/or to another device.

In some examples, only a first of devices602or606may continuously sense cardiac actively. The first device may continually determine, based on the sensed cardiac activity, occurrences of arrhythmias. In such examples, when the first device determines an occurrence of an arrhythmia, the first device may communicate the determination to the second device. Upon receiving a determination of an occurrence of an arrhythmia, the second device may begin to sense cardiac activity. Based on its sensed cardiac activity, the second device may also determine an occurrence of an arrhythmia. In such examples, only after the second device also determines an occurrence of an arrhythmia does system600begin to deliver appropriate electrical stimulation therapy to heart610.

In some examples, determining an occurrence of an arrhythmia may include determining a beginning of an arrhythmia, and system600may be configured to determine when to begin to deliver electrical stimulation therapy. In some examples, determining an occurrence of an arrhythmia may include determining an end of an arrhythmia. In such examples, system600may be configured to also determine when to cease to deliver electrical stimulation therapy. In examples where system600does not begin to deliver appropriate electrical stimulation therapy to heart610until multiple devices determine an occurrence of a cardiac arrhythmia, each of the determinations that do not trigger delivery of electrical stimulation therapy may be termed provisional determinations.

In examples where system600operates to deliver appropriate electrical stimulation therapy to heart610, if the determined arrhythmia is a tachycardia, either LCP602, LCP606, or both may deliver ATP therapy to heart610. In examples where the determined arrhythmia is a bradycardia, either LCP602, LCP606, or both may deliver bradycardia therapy to heart610. In examples where the determined arrhythmia is un-synchronized contractions, either pulse LCP602, LCP606, or both may deliver CRT to heart610.

Although not necessarily described inFIGS. 4-6, one of the two devices of systems400,500, or600could be a diagnostic-only device. In such examples, after one or more of the devices determined an occurrence of an arrhythmia, the diagnostic-only device may not deliver any electrical stimulation therapy. Rather, electrical stimulation therapy may be delivered by another device in the system that is capable of delivering appropriate electrical stimulation therapy, if desired.

FIG. 7illustrates an example medical device system700with three separate LCPs including LCP702, LCP704, and LCP706. Although system700is depicted with LCPs702,704, and706implanted within the LV, RV, and LA, respectively, other examples may include LCPs702,704, and706implanted within different chambers of the heart710. For example, system700may include LCPs implanted within both atria and one ventricle of the heart710. In other examples, system700may include LCPs implanted within both ventricles and one atria of heart710. More generally, it is contemplated that system700may include LCPs implanted within any combination of ventricles and atria. In some instances, system700may include two or more of LCPs702,704, and706implanted within the same chamber of the heart710.

In practice, such a system700may operate in accordance with any of the techniques described above with respect toFIGS. 4-6. In some instances, however, system may operate differently, at least to some degree. For example, before system700begins to deliver appropriate electrical stimulation therapy to the heart710, only a majority of LCPs702,704, and706may need to determine an occurrence of an arrhythmia. For example, in some instances, all of LCPs702,704, and706may be sensing cardiac activity and determining occurrences of arrhythmias independently. In some cases, only after a majority of LCPs702,704, and706determined an occurrence of an arrhythmia, may system700deliver appropriate electrical stimulation therapy to the heart710. In some instances, one of the LCP's is designated as the master LCP, and the other slave LCP's may communicate whether they determine an occurrence of an arrhythmia to the master LCP. The master LCP may then determine if a majority of the LCP's702,704, and706have determined an occurrence of an arrhythmia, and if so, may instruct the delivery of appropriate electrical stimulation therapy to the heart710. In some instances, the master LCP may instruct particular ones of the LCP's702,704, and706to deliver electrical stimulation therapy to the heart710, depending on the type and/or location of the detected arrhythmia.

Alternatively, and in some instances, only a single LCP may need to determine an occurrence of an arrhythmia before system700may begin to deliver appropriate electrical stimulation therapy to heart710. In yet other examples, all three of the LCP's702,704, and706may need to determine an occurrence of an arrhythmia before system700delivers appropriate electrical stimulation therapy to the heart710.

In some cases, only one LCP702,704, and706may actively sense cardiac activity and determine an occurrence of an arrhythmia. After determining an occurrence of an arrhythmia, the actively sensing device may communicate the determination to one or both of the other devices. In some cases, one or both of the other devices may then begin sensing for and determining occurrences of arrhythmias. In some instances, when a first one of the other devices determines an occurrence of an arrhythmia, system700may begin to deliver appropriate electrical stimulation therapy to heart710. In other instances, when both of the other devices determine an occurrence of an arrhythmia, system700may begin to deliver appropriate electrical stimulation therapy to heart710.

In some instances, LCPs702,704, and706may be set up in a daisy-chain configuration. For example, an actively sensing device may send a determination of an arrhythmia to only one of the other two devices (alternatively, only one of the two receiving devices may act upon the received determination from the actively sensing device). The receiving device may then begin actively sensing for and determining occurrences of arrhythmias. Upon determining an occurrence of an arrhythmia, the receiving device may communicate the determination to the last device. The last device may then begin sensing for and determining occurrences of arrhythmias. In some instances, only when the last device determines an occurrence of an arrhythmia does the system700begin to deliver appropriate electrical stimulation therapy to heart710.

Also in accord with the description of systems400,500, and700, in some examples, determining an occurrence of an arrhythmia may include determining a beginning of an arrhythmia, and system700may be configured to determine when to begin to deliver electrical stimulation therapy. In some examples, determining an occurrence of an arrhythmia may include determining an end of an arrhythmia. In such examples, system700may be configured to determine when to cease delivery of electrical stimulation therapy. In examples where system700does not begin to deliver appropriate electrical stimulation therapy to heart710until multiple LCP devices determine an occurrence of an arrhythmia, each of the determinations that do not trigger delivery of electrical stimulation therapy may be termed provisional determinations.

In examples where system700operates to deliver appropriate electrical stimulation therapy to heart710, if the determined arrhythmia is a tachycardia, one or more of LCPs702,704, and706may deliver ATP therapy to heart710. In examples where the determined arrhythmia is a bradycardia, one or more of LCPs702,704, and706may deliver bradycardia therapy to heart710. In examples where the determined arrhythmia is un-synchronized contractions, one or more of LCPs702,704, and706may deliver CRT to heart710. It is contemplated that less than all of LCPs702,704, and706may deliver electrical stimulation therapy in response to the detection of an arrhythmia. For example, only a single of LCPs702,704, and706may deliver electrical stimulation therapy. In other examples, two of LCPs702,704, and706may deliver electrical stimulation therapy.

In accordance with the above described description, one can see how such techniques may be extended to systems that have even more than three LCP devices. For example, in a four LCP device system, any of one, two, three, or four devices may be used to determine an occurrence of an arrhythmia before the system begins to deliver appropriate electrical stimulation therapy. In some such examples, all, some, or one of the LCP devices may initially actively sense and determine the occurrences of arrhythmias. In examples where less than all are initially actively sensing, once one of the actively sensing devices determines an occurrence of an arrhythmia, and communicates that determination to other devices of the system, at least one of the other devices of the system may begin to actively sense cardiac activity and determine occurrences of arrhythmias. Again, the techniques described above may be extended to systems that include any number of LCP devices or other devices, such as five, six, seven, or any other number that is practically feasible for implantation within a patient's body.

Additionally, although described above with respect to three or more LCP devices, the same techniques may be applied to any of the systems described with respect toFIGS. 4-5. For example, any of systems400and500may further include a third device, such as a second LCP device. In such systems, the three devices may operate in accordance with any of the above described techniques of system700, with the pulse generator capable of sensing for arrhythmias and/or delivering electrical stimulation therapy. In other examples, any of systems400and500may include a plurality of additional devices. For example, any of systems400and500may include three, four, five, or any number of LCP devices that are practical for implantation with a patient in addition to pulse generators406and506. Accordingly, in such examples, the devices may operate together in accordance with any of the above described techniques.

A multiple device system may, in some cases, be capable of delivering more effective electrical stimulation therapy than a single device system. For example, before beginning to deliver electrical stimulation therapy, example systems may determine which of the devices of the system first senses a depolarization wave of the heart. In such examples, such systems may direct the device which senses the depolarization wave first to deliver the electrical stimulation therapy. This may allow such systems to deliver electrical stimulation therapy at a site closer to the origin of an arrhythmia, which may increase the effectiveness of the electrical stimulation therapy.

In the example of system700, one of the devices of system700may determine an occurrence of a tachyarrhythmia, either individually or in addition to provisional determinations by other devices of system700in accordance with any of the techniques described above. One of the devices of system700(e.g. a master device) may determine to deliver ATP therapy to heart710or to determine to direct another device of system700to deliver ATP therapy. Before either delivering, or directing another device to deliver ATP therapy, one of the devices of system700may determine which device of system700first senses an intrinsic cardiac depolarization wave of heart710. The device that senses such a depolarization wave first may then begin delivery of ATP therapy.

The above description is just one example of how a system may operate to deliver electrical stimulation therapy by the device that senses the intrinsic cardiac depolarization wave of a heart first. In other examples, the type of arrhythmia and therapy may be different. Additionally, as such a feature is not tied to any particular configuration or number of devices, any of the systems described herein may further include such a feature. The only limitation in any system may be whether the devices of the system are capable of delivering the appropriate electrical stimulation therapy.

A multiple device system may be used to help provide discrimination between atrial arrhythmias and ventricular arrhythmias. For instance, example systems described herein may operate differently depending on whether an arrhythmia is an atrial arrhythmia or a ventricular arrhythmia in order to more effectively treat such arrhythmias.

As one illustrative example, one of the devices of system700may determine an occurrence of a tachyarrhythmia, either individually or in addition to provisional determinations by other devices of system700in accordance with any of the techniques described above. Additionally, a device of system700may determine whether the tachycardia is an atrial tachycardia or a ventricular tachycardia. If the tachycardia is an atrial tachycardia, one or more of the devices of system700may determine to not deliver electrical stimulation therapy. If the tachycardia is a ventricular tachycardia, one or more of the devices of system700may additionally determine whether the rate of the tachycardia is above a threshold and whether the cardiac electrical signal is a polymorphic signal. If the tachycardia rate is below the threshold and the cardiac electrical signal is not a polymorphic signal, one or more of the devices of system700may deliver, or direct a different device of system700to deliver, ATP therapy to the heart710. If the tachycardia rate is above the threshold or the cardiac electrical signal is a polymorphic signal, one or more of the devices of system700may deliver, or direct a different device of system700to deliver, a defibrillation pulse to heart710. Discriminating between such atrial and ventricular arrhythmias, and responding differently to the different types of arrhythmias, may increase the effectiveness of delivered electrical stimulation therapy and decrease negative outcomes of any delivered electrical stimulation therapy. The above description is just one example of how the disclosed systems may operate to discriminate between various arrhythmias and deliver electrical stimulation therapy in response to the different determined arrhythmias.

FIGS. 8 and 9illustrate other example implantation locations and configurations for a multiple device medical system. For example, medical device system800ofFIG. 8shows three LCP devices, LCPs802,804, and806. Two of the LCP devices, LCPs802and804, are shown implanted within a single chamber of heart810. In other examples, all three devices may be implanted within a single chamber of heart810. Although two LCP's802and804are shown implanted within the LV of heart810, in other examples, any of the chambers of heart810may include multiple implanted LCP devices. Implanting multiple devices within a single chamber may enhance the effectiveness of delivered electrical stimulation, as the multiple devices may increase the chances of delivering electrical stimulation therapy near a cardiac site that is an origin of an arrhythmia causing signal. As described previously with respect to the other systems, any of the other system described herein, such as systems400and500may include one or more devices implanted within a single chamber of the heart, as desired.

Medical device system900ofFIG. 9includes an LCP902implanted on an epicardial surface of heart910. LCPs904and906are shown implanted on an endocardial surface of heart910. In some instances, one or more additional devices of system900may be implanted on an epicardial surface. In some instance, a device implanted on an epicardial surface of a heart may sense intrinsic cardiac electrical signals and/or deliver appropriate electrical stimulation therapy to the heart. Accordingly, any of the systems described herein may include one or more devices implanted on an endocardial surface of a heart, as desired.

As noted above, in some embodiments, one device in a medical system may act a master device and the other devices may act as slave devices.FIG. 10is a block diagram of an illustrative medical device system1000that includes a master device1002and multiple slave devices1004,1006, and1008. In the example shown, the master device1002may conductively communicate with the slave devices1004,1006, and1008through the body of the patient. In other examples, the master and slave devices may communicate via a different communication mechanism, such as through radiofrequency (RF) signals, inductive coupling, optical signals, acoustic signals, or any other suitable for communication mechanism, as desired.

In one example, the master device1002may be an ICD device, for example, an ICD or an S-ICD, and may be configured to receive cardiac information from one or more slave devices1004,1006, and1008. In some cases, the slave devices may be LCP's. The communicated cardiac information may include, for example, cardiac electrical signals sensed by the slave devices1004,1006, and1008, preliminary determinations made by the slave devices1004,1006, and1008, or other information sensed or determined by the slave devices1004,1006, and1008. In some examples, master device1002may also sense cardiac activity. In such examples, master device1002may determine occurrences of arrhythmias based on either its own sensed cardiac activity and/or the received cardiac activity from the slave devices1004,1006and1008. In some instances, master device1002may determine that the cardiac activity from one or multiple devices of system1000indicates an occurrence of an arrhythmia. In some cases, although multiple devices of system1000may each be sensing cardiac activity, only a single device, such as master device1002, may make the determination that a cardiac arrhythmia is occurring and that an appropriate electrical stimulation therapy is desired.

In response to determining an occurrence of an arrhythmia, master device1002may determine to deliver electrical stimulation therapy. In one example, master device1002may determine an appropriate electrical stimulation therapy based on the type of arrhythmia. Additionally, master device1002may determine which device or devices should deliver the electrical stimulation therapy. Master device1002may direct one or more of the devices, which might include the master device itself, to actually deliver the desired electrical stimulation therapy. Master device1002may operate according to any of the previously disclosed techniques. For example, master device1002may determine one or more provisional determinations of occurrences of arrhythmias before determining an actual occurrence of an arrhythmia. Master device1002may additionally distinguish between atrial and ventricular arrhythmias and determine appropriate electrical stimulation therapy to deliver based on the determined type of arrhythmia. In some examples, master device1002may determine which device or devices need to deliver electrical stimulation therapy based on which device or devices sensed the cardiac depolarization wave first of a cardiac cycle.

In some instances, multiple devices of system1000may determine occurrences of arrhythmias. For example, slave devices1004,1006, and1008may each determine occurrences of arrhythmias and may communicate such determinations to master device1002. In some examples, such determinations may be considered actual or provisional determinations. Based on such received determinations, master device1002may determine an occurrence of an arrhythmia, in accordance with any of the previously disclosed techniques. Based on an determination of an arrhythmia, master device1002may deliver, and/or direct one or more of slave devices1004,1006, and1008to deliver, appropriate electrical stimulation therapy.

In some cases, not all of master device1002and slave devices1004,1006, and1008may be actively sensing for an arrhythmia. For instance, as described previously, in some examples only a single, or less than all of master device1002and slave devices1004,1006, and1008, may be actively sensing for an arrhythmia. In at least one example, the actively sensing device may be sending cardiac activity to master device1002. Based on the received cardiac activity, master device1002may determine an occurrence of an arrhythmia. After determining an occurrence of an arrhythmia, master device1002may direct a second device of system1000to begin actively sensing cardiac activity. This second device may additionally communicate sensed cardiac activity to master device1002. Again, master device1002may determine an occurrence of an arrhythmia based on the received cardiac activity from the second device. After making one or more determinations of an occurrence of an arrhythmia, master device1002may deliver, or direct one or more of slave devices1004,1006, and1008to deliver, appropriate electrical stimulation therapy. In other examples, instead of sending sensed cardiac data, the devices may send determinations of occurrences of an arrhythmia to master device1002. In some cases, master device1002may not sense cardiac activity. Rather, master device1002may make determinations of occurrences of cardiac arrhythmias based on received cardiac activity and/or determinations from those slave devices that are sensing cardiac activity.

In some cases, master device1002may be an LCP device, an external cardioverter-defibrillator, ICP, or diagnostic-only device. In some examples, master device1002and the slave devices1004,1006, and1008may have similar hardware configuration; however, they may have different software installed. In some examples, the slave devices1004,1006, and1008may be set to a “slave mode” while master device1002may be set to a “master mode”, even though all devices share the same hardware and software features. Additionally, in some examples, the devices of system1000may switch between being configured as a master device and a slave device. For example, an external programmer may connect to any of the devices of such systems and alter the programming of any of the devices of the system, as desired.

FIGS. 11-22are flow diagrams showing various methods that can be implemented by exemplary medical systems described above, for example, systems400,500,600,700, or any other exemplary medical systems described herein. Such exemplary systems may include any of MD100and/or LCP200ofFIGS. 1 and 2or any of the other devices described herein. In particular, the methods illustrated may help identify and treat arrhythmias and/or other conditions of a patient

In an illustrative method1100ofFIG. 11, a device of a medical device system may sense cardiac activity of the heart, as shown at1102. The medical device may be an ICD, S-ICD, LCP, a diagnostic only device, or any other device as desired. The illustrative method may include sensing cardiac activity of the heart using a first leadless cardiac pacemaker (LCP), the first leadless cardiac pacemaker may be spaced from the medical device while being coupled to the medical device via a communication pathway, as shown at1104. The communication pathway may be, for example, any of those described with respect toFIG. 3. In at least some examples, the communication pathway may pass through at least a portion of the body of the patient. One or more devices of the system may determine an occurrence of a tachyarrhythmia based, at least in part, on the cardiac activity sensed by the medical device and the first leadless cardiac pacemaker, as shown at1106. The determination of an occurrence of a tachycardia may be made based on either the individual cardiac activity sensed by the medical device or by the first leadless cardiac pacemaker, or the combination of the sensed cardiac activity of the two devices. In some examples, the cardiac information may include both sensed cardiac electrical signals and information from other devices such as accelerometers, heart sound sensors, blood pressure sensor, blood-oxygen sensors, and the like.

In some cases, the first LCP may make a provisional determination of the occurrence of a tachycardia based on the cardiac activity sensed by the first LCP. The first LCP may send the provisional determination to the medical device. The medical device may independently make a provisional determination of the occurrence of a tachycardia based on the cardiac activity sensed by the medical device. A determination of the occurrence of a tachycardia may then be based on the provisional determination made by the first LCP and the medical device.

In some instances, the first LCP may not make a provisional determination of the occurrence of a tachycardia, but rather may send the cardiac activity sensed by the first LCP to the medical device. The medical device may then receive the cardiac activity sensed by the first LCP, and may determine the occurrence of a tachycardia based on the cardiac activity sensed by the first LCP and the cardiac activity sensed by the medical device.

In another illustrative method1200, as shown inFIG. 12, two or more LCPs can autonomously identify tachycardia episodes and deliver ATP. In particular, an exemplary system, such as any of those described herein, may sense cardiac activity of the heart using a first leadless cardiac pacemaker (LCP), wherein the first leadless cardiac pacemaker is configured to detect cardiac events at a first location of the heart and to deliver ATP therapy to the first location, as shown at1202. Additionally, a second leadless cardiac pacemaker (LCP) may be configured to detect cardiac events at a second location of the heart and to deliver ATP therapy to the second location of the heart, as shown at1204. One or more of the first and second LCPs may be configured to determine an occurrence of a tachyarrhythmia based, at least in part, on the cardiac events detected by the first leadless cardiac pacemaker and/or the cardiac events detected by the second leadless cardiac pacemaker, as shown at1206. Once one or more of the LCPs determines an occurrence of a tachyarrhythmia, at least one of the first and the second leadless cardiac pacemaker may deliver ATP therapy to the heart, as shown at1208.

In at least one example, the first leadless cardiac pacemaker may act as a master and the second leadless cardiac pacemaker may act as a slave. In such scenario, the first leadless cardiac pacemaker may make a determination of a tachyarrhythmia and cause the first LCP, second LCP, or both to deliver ATP therapy to the heart. In another example, the first and the second leadless cardiac pacemaker together may determine an occurrence of a tachyarrhythmia and both the first and second leadless cardiac pacemakers may deliver the ATP therapy to the heart.

In another illustrative method1300, as shown inFIG. 13, a medical device system, such as system400,500,600, or any other medical device system described herein may include a leadless cardiac pacemaker (LCP) that may be triggered by an external device (e.g. a device external to the LCP) such as an implantable cardioverter defibrillator (ICD) or subcutaneous-ICD (S-ICD) to deliver an ATP therapy. The system may include sensing of the cardiac activity of the heart using a first leadless cardiac pacemaker (LCP), where the first leadless cardiac pacemaker may be configured to detect cardiac events at a first location of the heart and may also be configured to deliver ATP therapy to that location, as shown at1302. Based at least in part on the cardiac events detected by the first leadless cardiac pacemaker, one or more devices of the system may determine an occurrence of a tachyarrhythmia, as shown at1304. Once one or more of the devices have determined an occurrence of a tachyarrhythmia, an ICD or S-ICD of the system may begin charging for a defibrillation pulse, and also may instruct the first leadless cardiac pacemaker to deliver ATP therapy to the heart, as shown at1306. The first leadless cardiac pacemaker may deliver the ATP therapy to the heart at least while the ICD or S-ICD is charging for a defibrillation pulse. If one or more of the devices subsequently determines that the ATP therapy was successful in terminating the tachyarrhythmia, the ICD or S-ICD may subsequently discharge the charged energy without delivering the defibrillation pulse. Otherwise, the ICD or S-ICD may deliver the defibrillation pulse once the ICD or S-ICD is fully charged and ready to deliver the defibrillation pulse.

Generally, one or more episodes of ventricular tachyarrhythmia in a patient may be followed by a ventricular fibrillation episode. A medical system including one or more LCPs and an ICD may be useful in treating a scenario of overlapping tachyarrhythmia and fibrillation episodes more effectively than systems that do not include both such devices.

The illustrative method1400, shown inFIG. 14, may be implemented by any system described herein that includes both an LCP device and an implantable cardioverter-defibrillator device. Illustrative method1400may include delivering an ATP therapy that may be synchronized between a leadless cardiac pacemaker and an implantable cardioverter defibrillator. As a first step of this illustrative method, cardiac activity of the heart may be sensed by a first leadless cardiac pacemaker (LCP), which may be configured to detect cardiac events at a first location of the heart and is further configured to deliver (ATP) therapy to that first location, as shown at1402. One or more devices of the system may further determine an occurrence of a tachyarrhythmia based on, either partially or completely, the cardiac events detected by the first leadless cardiac pacemaker, as shown at1404. In some examples, this may be done by comparing the cardiac activity detected by the first leadless cardiac pacemaker to a threshold cardiac activity of a normal patient or of a normal rhythm of the present patient. After determining an occurrence of a tachyarrhythmia, one or more devices of the system may cause the first leadless cardiac pacemaker to deliver ATP therapy, sometimes synchronously with ATP therapy delivered with an external device, such as the ICD (1406).

FIG. 15includes an illustrative method1500that may be implemented by a system that includes an LCP and an ICD. Such system can include a first leadless cardiac pacemaker (LCP) that can sense cardiac activity and which may be communicatively coupled to an ICD, as shown at1502. In some cases, the first leadless cardiac pacemaker may be configured to detect cardiac events at a first location of the heart and may be configured to deliver ATP therapy to the first location. One or more devices of the system may determine an occurrence of a tachyarrhythmia based on the cardiac events detected by the first leadless cardiac pacemaker, as shown at1504. Once one or more of the devices of the system determined an occurrence of a tachyarrhythmia, the first leadless cardiac pacemaker may deliver ATP therapy to the heart based on an ATP therapy protocol, as shown at1506. In some examples, the particular ATP therapy protocol may be communicated to the first leadless cardiac pacemaker from the ICD. In some instances, the ICD may act as a master device that can dictate the electrical impulses that are to be delivered to the first location of the heart.

FIG. 16discloses another illustrative method1600which may be implemented by a system that includes an LCP device and an ICD device. Such system may sense the cardiac activity using a first leadless cardiac pacemaker (LCP) that may be configured to detect one or more cardiac events based on, either partially or completely, cardiac mechanical information as shown at1602. The cardiac mechanical information may include the contraction or relaxation of the cardiac muscles, such as by using an accelerometer, a heart sounds sensor, a blood pressure sensor, a blood-oxygen sensor, or any other sensor capable of sensing mechanical information of the heart. The first leadless cardiac pacemaker may be configured to detect cardiac events at a first location of the heart and can deliver ATP therapy to the first location. One or more devices of the system may further determine an occurrence of a tachyarrhythmia based, at least in part, on the cardiac events detected by the first leadless cardiac pacemaker, as shown at1604. Once one or more devices determine an occurrence of a tachyarrhythmia, one or more devices may cause the first leadless cardiac pacemaker to deliver ATP therapy to the heart, as shown at1606.

In the illustrative method1700shown inFIG. 17, a first leadless cardiac pacemaker (LCP) may sense cardiac activity, as shown at1702. The first leadless cardiac pacemaker may be configured to detect cardiac events at a first location of the heart and may be configured to deliver ATP therapy to the first location. One or more devices of the system may determine an occurrence of a tachyarrhythmia based, at least in part, on the cardiac events detected by the first leadless cardiac pacemaker (1704). Once a tachyarrhythmia is identified, one or more devices of the system may determine if the tachyarrhythmia is susceptible to ATP therapy, as shown at1706. This may be determined based, at least in part, on the cardiac events detected by the first leadless cardiac pacemaker. For example, one or more devices of the system may determine whether the tachyarrhythmia is an atrial tachyarrhythmia or a ventricular tachyarrhythmia. Additionally, one or more devices of the system may determine whether the tachycardia rate is above threshold. Some systems may further include one or more devices that determine whether the tachycardic signal is a polymorphic signal. Based on these determinations, one or more devices may determine whether the tachyarrhythmia is susceptible to ATP therapy. Once the tachyarrhythmia is determined to be susceptible to the ATP therapy, one or more devices may cause the first leadless cardiac pacemaker to deliver ATP therapy to the heart, and in some cases, may cause an implantable cardioverter defibrillator to suspend delivering defibrillation shock therapy at least during delivery of ATP therapy, as shown at1708.

FIG. 18describes another illustrative method1800. A first leadless cardiac pacemaker of the system may sense cardiac activity of the heart, as shown at1802. The first leadless cardiac pacemaker may determine an occurrence of a tachyarrhythmia, as shown at1804. Once the first leadless cardiac pacemaker has determined an occurrence of a tachyarrhythmia, the first leadless cardiac pacemaker may determine if the tachyarrhythmia is susceptible to ATP therapy, as shown at1806. The steps1804and1806may be completed based, at least in part, on the cardiac events detected by the first leadless cardiac pacemaker. Additionally, one or more devices of the system (which may be the first leadless cardiac pacemaker) may determine whether the tachycardic rate is above a threshold and whether the tachycardia signal is polymorphic. If a device other than the first leadless cardiac pacemaker determines one or more of these parameters, the device may in some cases communicate such parameters to the first leadless cardiac pacemaker. If the first leadless cardiac pacemaker determines that the tachyarrhythmia is susceptible to ATP therapy, the first leadless cardiac pacemaker may deliver ATP therapy to the heart, as shown at1808. Accordingly, in such systems, an LCP device may autonomously determine an occurrence of a tachyarrhythmia and take action based on the determination.

FIG. 19shows another illustrative method1900. InFIG. 19, a first leadless cardiac pacemaker (LCP) may be communicatively coupled to an implantable cardioverter defibrillator (ICD), as shown at1902. The first leadless cardiac pacemaker may be configured to detect cardiac events at a first location of the heart and further configured to deliver anti-tachycardia pacing (ATP) therapy. One or more devices of the system may determine an occurrence of a tachyarrhythmia based, at least in part, on the cardiac events detected by the first leadless cardiac pacemaker, as shown at1904. Once one or more devices of the system have determined an occurrence of a tachyarrhythmia, the first leadless cardiac pacemaker may be made to communicate status information about a delivery of ATP therapy by the first leadless cardiac pacemaker to the implantable cardioverter defibrillator (ICD), as shown at1906. For example, the first leadless cardiac pacemaker may communicate an intent to deliver ATP therapy to the implantable cardioverter defibrillator (ICD) or that the first leadless cardiac pacemaker is currently delivering ATP therapy. In some examples, the first leadless cardiac pacemaker may communicate that the first leadless cardiac pacemaker will not deliver ATP therapy.

FIG. 20shows another illustrative method2000. InFIG. 20, a first leadless cardiac pacemaker (LCP) may be configured to detect cardiac events at a first location of the heart. One or more devices of the system may determine, based at least in part on the cardiac events detected by the first leadless cardiac pacemaker, an occurrence of a tachyarrhythmia, as shown at2004. In a next step, the first leadless cardiac pacemaker may communicate information about the tachyarrhythmia to an implantable cardioverter defibrillator (ICD), as shown at2006. For example, the first leadless cardiac pacemaker may communicate such information about the tachyarrhythmia such as the tachycardic rate, whether the tachycardic rate is above a threshold, and/or whether the tachycardia signal is polymorphic.

Another illustrative method2100is shown inFIG. 21. A first leadless cardiac pacemaker (LCP) may be configured to detect cardiac events at a first location of the heart, as shown at2101. Based on the cardiac events detected, the first leadless cardiac pacemaker may determine an occurrence of a tachyarrhythmia, as shown at2104. After determining an occurrence of a tachyarrhythmia, the first leadless cardiac pacemaker may communicate information about the tachyarrhythmia to a second leadless cardiac pacemaker, as shown at2106. For example, the first leadless cardiac pacemaker may communicate information such as the tachycardic rate, whether the tachycardic rate is above a threshold, and/or whether the tachycardia signal is polymorphic.

FIG. 22shows another illustrative method2200. A first leadless cardiac pacemaker (LCP) may be configured to detect cardiac events at a first location of the heart, as shown at2202. The first leadless cardiac pacemaker may determine an occurrence of a tachyarrhythmia based, at least in part, on the cardiac events detected by the first leadless cardiac pacemaker, as shown at2204. After determining an occurrence of a tachyarrhythmia, the first leadless cardiac pacemaker may communicate information about the tachyarrhythmia to an implantable cardioverter defibrillator, as shown at2206. For example, the first leadless cardiac pacemaker may communicate information such as the tachycardic rate, whether the tachycardic rate is above a threshold, and/or whether the tachycardia signal is polymorphic. The implantable cardioverter defibrillator may determine whether to deliver therapy according to a therapy protocol, based at least in part on the communicated information about the tachyarrhythmia, as shown at2208.

FIG. 23shows another illustrative method2300. Cardiac activity may be sensed by a medical device, as shown at2302. Cardiac activity may also be sensed by a first leadless cardiac pacemaker, wherein the first leadless cardiac pacemaker is communicatively coupled to the medical device, sometimes via a communication pathway that includes the body of the patient, as shown at2304. One or more of the medical device and the first leadless cardiac pacemaker may then determine if a tachyarrhythmia is occurring based, at least in part, on the cardiac activity sensed by the medical device and/or the cardiac activity sensed by the first leadless cardiac pacemaker, as shown at2306. After determining that a tachyarrhythmia is occurring, one or more of the medical device and the first leadless cardiac pacemaker may determine a type of the tachyarrhythmia based, at least in part, on both the cardiac activity sensed by the medical device and the cardiac activity sensed by the first leadless cardiac pacemaker, as shown at2308. In this example method, the cardiac activity sensed by the first leadless cardiac pacemaker may help discriminate between types of arrhythmia. In this example, the method device may include an ICD, a SICD, another leadless cardiac pacemaker, or any other suitable device.

In some instances, cardiac activity may also be sensed by a second leadless cardiac pacemaker. In some cases, one or more of the medical device, the first leadless cardiac pacemaker, and the second leadless cardiac pacemaker may determine if a tachyarrhythmia is occurring based, at least in part, on the cardiac activity sensed by the medical device, the cardiac activity sensed by the first leadless cardiac pacemaker, and/or the cardiac activity sensed by the first leadless cardiac pacemaker. After determining a tachyarrhythmia is occurring, one or more of the medical device, the first leadless cardiac pacemaker and the second leadless cardiac pacemaker may determine a type of the tachyarrhythmia based, at least in part, on the cardiac activity sensed by two or more of the medical device, the first leadless cardiac pacemaker and the second leadless cardiac pacemaker. This is another example.

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.

Additional Examples

In a first example, a method of identifying a tachyarrhythmia of a heart of a patient comprises sensing cardiac activity by a medical device, sensing cardiac activity by a first leadless cardiac pacemaker, wherein the first leadless cardiac pacemaker is spaced from the medical device and communicatively coupled to the medical device via a communication pathway that includes the body of the patient, and determining if a tachyarrhythmia is occurring based, at least in part, on both the cardiac activity sensed by the medical device and the cardiac activity sensed by the first leadless cardiac pacemaker.

In addition or alternatively, and in a second example, the medical device of the first example may comprise a second leadless cardiac pacemaker, and the second leadless cardiac pacemaker may be implanted at an atrium of the heart and the first leadless cardiac pacemaker may be implanted at a ventricle of the heart.

In addition or alternatively, and in a third example, the medical device of any of the first or second examples may comprise a second leadless cardiac pacemaker, and the second leadless cardiac pacemaker may be implanted at a left ventricle of the heart and the first leadless cardiac pacemaker may be implanted at a right ventricle of the heart.

In addition or alternatively, and in a fourth example, the medical device of any of the first through third examples may comprise a second leadless cardiac pacemaker, and the second leadless cardiac pacemaker may be implanted on an endocardial surface of the heart and the first leadless cardiac pacemaker may be implanted on an epicardial surface of the heart.

In addition or alternatively, and in a fifth example, the one of the medical device and the first leadless cardiac pacemaker of any of the first through fourth examples may perform the determining step after receiving cardiac information from the other of the medical device and the first leadless cardiac pacemaker via the communication pathway.

In addition or alternatively, and in a sixth example, the cardiac information of any of the first through fifth examples may include cardiac activity sensed by the other of the medical device and the first leadless cardiac pacemaker.

In addition or alternatively, and in a seventh example, the cardiac information of any of the first through sixth examples may include a provisional determination of tachyarrhythmia determined by the other of the medical device and the first leadless cardiac pacemaker.

In addition or alternatively, and in an eighth example, the medical device of any of the first through seventh examples may comprise one of a second leadless cardiac pacemaker, an implantable pulse generator, and a diagnostic-only medical device.

In addition or alternatively, and in a ninth example, one of the medical device and the first leadless cardiac pacemaker of any of the first though eighth examples is a master device and wherein the other of the medical device and the first leadless cardiac pacemaker is a slave device.

In addition or alternatively, and in a tenth example, any of the first through ninth examples may, upon determining an occurrence of a tachyarrhythmia, deliver anti-tachycardia pacing (ATP) therapy to the heart.

In an eleventh example, a medical system for identifying a tachyarrhythmia in a heart of a patient comprises a plurality of leadless cardiac pacemakers configured to detect cardiac activity at corresponding locations of the heart, and an Implantable Cardioverter Defibrillator (ICD) communicatively coupled to each of the plurality of leadless cardiac pacemakers via a communication pathway that includes the body of the patient, the ICD determining if a tachyarrhythmia is occurring based, at least in part, on the cardiac activity detected by two or more of the plurality of leadless cardiac pacemakers.

In addition or alternatively, and in a twelfth example, the ICD of the eleventh example may be a sub-cutaneous ICD with one or more sub-cutaneous electrodes.

In addition or alternatively, and in a thirteenth example, the cardiac activity that is detected by the two or more of the plurality of leadless cardiac pacemakers of any of the eleventh or twelfth examples may include detecting a tachyarrhythmia at the corresponding location of the heart.

In addition or alternatively, and in a fourteenth example, the ICD of any of the eleventh through thirteenth examples may determine that a tachyarrhythmia is occurring if a majority of the two or more of the plurality of leadless cardiac pacemakers determine that a tachyarrhythmia is occurring.

In addition or alternatively, and in a fifteenth example, the two or more of the plurality of leadless cardiac pacemakers of any of the eleventh through fourteenth examples may be disposed at multiple ventricular sites in the heart.

In addition or alternatively, and in a sixteenth example, the ICD of any of the eleventh through fifteenth examples may be configured to detect cardiac activity of the heart, and wherein the ICD is configured to determine if a tachyarrhythmia is occurring based, at least in part, on the cardiac activity detected by two or more of the plurality of leadless cardiac pacemakers and the cardiac activity detected by the ICD.

In addition or alternatively, and in a seventeenth example, the ICD of any of the eleventh through sixteenth examples may determine which of the plurality of leadless cardiac pacemakers deliver ATP therapy when the ICD determines that a tachyarrhythmia is occurring.

In an eighteenth example, a method of identifying a tachyarrhythmia of a heart of a patient comprises sensing cardiac activity by a medical device, sensing cardiac activity by a first leadless cardiac pacemaker, wherein the first leadless cardiac pacemaker is communicatively coupled to the medical device via a communication pathway that includes the body of the patient, determining by one or more of the medical device and the first leadless cardiac pacemaker, if a tachyarrhythmia is occurring based, at least in part, on the cardiac activity sensed by the medical device and/or the cardiac activity sensed by the first leadless cardiac pacemaker, and after determining a tachyarrhythmia is occurring, determining, by one or more of the medical device and the first leadless cardiac pacemaker, a type of the tachyarrhythmia based, at least in part, on both the cardiac activity sensed by the medical device and the cardiac activity sensed by the first leadless cardiac pacemaker. In some instances, the type of the tachyarrhythmia comprises one of a ventricular tachyarrhythmia or an atrial tachyarrhythmia.

In addition or alternatively, and in a nineteenth example, the eighteenth example may comprise delivering a first therapy to the heart based on a determined first type of tachyarrhythmia, and delivering a second therapy to the heart based on a determined second type of tachyarrhythmia.