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Method and apparatus for communication between a handheld programmer and an implantable medical device

Method and apparatus for communication between a handheld programmer and an implantable medical device description/claims

This application is a continuation of U.S. application Ser. No. 10/835,043, filed Apr. 29, 2004, the entirety of which is incorporated herein by reference.

The present device relates generally to implantable medical devices and particularly, but not by way of limitation, to an external device that can communicate with an implantable device to monitor and control its operation.

When functioning properly, the human heart maintains its own intrinsic rhythm based on physiologically-generated electrical impulses. It is capable of pumping adequate blood throughout the body's circulatory system. Each complete cycle of drawing blood into the heart and expelling it is referred to as a cardiac cycle.

However, some people have abnormal cardiac rhythms, referred to as cardiac arrhythmias. Such arrhythmias result in diminished blood circulation. Arrhythmias can occur in the upper chambers of the heart—the atria, or the lower chambers of the heart—the ventricles. However, ventricular arrhythmias present the most serious health risk as they can lead to rapid death from the lack of circulation. Arrhythmias can be subdivided further into specific conditions of the heart that represent vastly different manifestations of abnormal cardiac rhythm. These conditions are bradycardia, or a slow heartbeat, and tachycardia, or a fast heart beat.

One mode of treating a cardiac arrhythmia uses an implantable medical device (“IMD”). Such implantable medical devices include pacemakers, also referred to as pacers, and defibrillators. The traditional use of a pacemaker is to treat a person with bradycardia. In other words, pacemakers help speed up the cardiac cycle of a person whose heart beats too slowly. Pacers accomplish this by delivering timed sequences of low energy electrical stimuli, called pace pulses, to the heart. Such stimuli are delivered via an intravascular lead wire or catheter (referred to as a “lead”) having one or more electrodes disposed in or about the heart.

In comparison to a pacemaker, an implanted defibrillator applies a much stronger electrical stimulus to the heart. This is sometimes referred to as a defibrillation countershock, also referred to simply as a “shock.” The shock changes ventricular fibrillation to an organized ventricular rhythm or changes a very rapid and ineffective cardiac rhythm to a slower, more effective rhythm. Defibrillators help treat cardiac disorders that include ventricular fibrillation, ventricular tachycardia, atrial fibrillation, and atrial flutter. These inefficient or too rapid heartbeats reduce the pumping efficiency of the heart and thereby diminish blood circulation. The countershock delivered by the defibrillator interrupts the tachyarrhythmia, allowing the heart to re-establish a normal rhythm for the efficient pumping of blood.

The cardiac rhythm management devices discussed above may also include a wireless sending and receiving capability that permits an external programmer or controller to send instructions and receive data from the implanted device. Such a controller permits communication with the implanted device without the need to physically access the implanted device. Such controllers are known for use by physicians or other medical personnel to monitor and control the function of the implanted device.

The monitoring or interrogation mode of an external programmer or controller is used primarily as a follow-up tool to evaluate the implanted device and patient during subsequent office visits. This mode is very important for patients who have an implanted defibrillator because, typically, no other means exist to efficiently evaluate the condition or effectiveness of the device. Normally, patients have to schedule periodic and frequent visits with a clinician to have the device checked and may require surgery if an anomaly is detected.

Such controllers, with limited sets of commands, are known to permit a patient to have some control over the function of the implanted device. However, patient-operated controllers may require an electrical cord providing power from a wall outlet or other external power source and may include text based messages to communicate with the patient regarding the status of the implanted device and to acknowledge receipt of an instruction by the implanted device.

U.S. Pat. No. 5,311,449 to Adams discloses a sterilizable, hand-held programmer/interrogator for communication with an implanted defibrillator. The device uses radio frequency (RF) telemetry to communicate and transmit data to the defibrillator. Device programming and interrogation are controlled by “function control keys,” an “electromechanical key” that controls the device's functionality and a “display.” The display allows retrieved data to be shown serially on two lines of sixteen characters each. The '449 patent does not disclose a touch-sensitive, color screen as a display option or the ability to communicate with other sensors adapted to monitor other physiological parameters.

U.S. Pat. No. 6,006,132 to Tacker, Jr., et al., discloses a non-implantable communication device that is hand-held and adapted to communicate with an implantable atrial defibrillation device to monitor the status of the device and program its operation. According to the '132 patent, the hand-held communication device is adapted to provide positive feedback to the patient when making an external command by including both an acknowledgement that the command was received and a description of the task being performed by the implantable device in response to the command. However, the '132 patent does not disclose a use of the hand-held communication device beyond its compatibility with an atrial defibrillator. In addition, the disclosed device is essentially a portable communication device with control commands that are “vastly limited as compared to the control commands which may be derived from the external programmer,” preferably, “simple mode select commands, a therapy sequence control command, and a status request control command.” See '132 patent, Col. 5, ll. 16-21. Consequently, the '132 patent does not disclose or teach a hand-held external programmer with robust command and interrogation capabilities.

U.S. Pat. No. 6,249,703 to Stanton el al. also discloses a portable programmer. The programmer provides tactile, audible, and visible feedback to the user to convey information regarding the proper (or improper) operation of the programmer and the implanted device. However, as shown in FIG. 2 of the patent, user input keys 19, 20, 21, and 22 are limited to pre-programmed uplink and downlink operations and are generally incapable of providing robust input or device interrogation means.

U.S. Pat. No. 6,381,496 to Meadows et al. describes a hand-held programmer for implantable or non-implantable devices that includes an electronically stored set of transmittable operational parameters for the device. Suitable devices include spinal cord stimulators, neural stimulators and sensors, deep brain stimulators, cochlear stimulators, drug delivery systems and muscle tissue stimulators. The programmer is further adapted to receive telemetric data from the device and, based on that input, change the device's operational parameters within certain pre-defined limits. Telemetry may be accomplished with modulated RF signals. The patent further discusses a touch screen display as one way to control the operation of the programmer. However, the '496 patent does not discuss the programmer as a device with robust analytical capabilities accessible by the clinician or patient. Nor does the patent discuss the programmer as a component of a larger network of medical devices. In essence, the '496 patent addresses the need of providing a device with context switching, which is changing one set of operational parameters to another set.

U.S. published patent application no. 2001/0041920, application Ser. No. 09/769,201, describes a hand-held communication device capable of transmitting data to or receiving data from a medical device, preferably an infusion pump. The transmitted data is primarily directed towards replacement or upgrade software for the medical device. In addition, the communication device is capable of transmitting patient definable parameters that can be used to modify the treatment or monitoring performed by the medical device. However, the application does not teach or disclose the use of the communication device as a component of a network of devices or a robust analytical tool capable of displaying device parameters and functions for access and modification by the patient or a clinician.

Similarly, U.S. published patent application no. 2001/0173830, application Ser. No. 09/768,207, describes a communication device of the type described in the '201 application discussed above. However, this application focuses on improving the communication link between the IMD and the communication device by minimizing the risk of synchronization loss between transmitted and received bits of data.

U.S. published patent application no. 2002/0082665, application Ser. No. 09/765,484, describes a system for monitoring and programming an implantable medical device. However, the system comprises a communication module operably connected to a mobile telephone and/or a personal digital assistant (“PDA”). The application does not teach or disclose a communication unit that can program an IMD without the need for a wireless phone or PDA to bridge communication between the IMD and a remote computer system or health care provider.

Another example of a hand-held device for use with an implantable medical device is discussed in U.S. published patent application no. 2002/0072785, application Ser. No. 10/068,478. However the '478 application discusses the use of a hand-held personal data manager (“PDM”) that essentially serves as a data messenger between the implantable medical device, a programmer and a networked data center. The '478 application does not teach or disclose a hand-held programmer that supplants the need for a PDM data bridge.

None of these references discloses or teaches the functionality of a programmer in the size of a handheld device. In fact, the programmers in the prior art act primarily as repeaters, but are not adapted to process telemetry data and present such data in a user-friendly format. As known to those of skill in the art, a repeater comprises a system and device that electronically collects information from an implantable medical device and transmits that information to a centralized computer network or server for analysis.

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