iRhythm Inc v. Welch Allyn Inc

1. Case Identification

• Case #: IPR2025-00378
• Patent #: 8,214,007
• Filed: December 23, 2024
• Petitioner(s): iRhythm, Inc.
• Patent Owner(s): Welch Allyn, Inc.
• Challenged Claims: 1-6, 8, 10-15, 29, 31-35, 37-39, and 43-45

2. Patent Overview

• Title: Body-Worn Patient Monitoring Device
• Brief Description: The ’007 patent discloses a body-worn physiological monitor, such as an electrocardiogram (ECG), comprising a disposable module for skin contact and a separate, reusable communication-computation module. The invention is directed at using "resistive traces" printed on the disposable module to serve as current-limiting resistors, which protect the electronic components from defibrillation events without requiring the bulky power resistors used in prior art devices.

3. Grounds for Unpatentability

Ground 1: Obviousness over Matsumura and Kroll - Claims 1, 2, 4-6, 8, 10-15, 29, 31, 37, 38, and 43-45 are obvious over Matsumura in view of Kroll and general knowledge.

• Prior Art Relied Upon: Matsumura (Japanese Patent Publication 2004-121360) and Kroll (Patent 4,763,660).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Matsumura teaches the core elements of the claimed device, including a body-worn bioelectric potential detector with a disposable bioelectrode pad and a reusable, removable signal processor. However, Matsumura lacks an explicit teaching of integrated defibrillation protection. Kroll was argued to supply this missing element by teaching a disposable electrode belt that uses "lead strips" made from a "flexible conductive ink compound" with a preselected resistance to serve as a current limiter, protecting the patient and associated devices.
  • Motivation to Combine: A POSITA would combine Kroll's teaching of resistive traces with Matsumura's wearable monitor to achieve several predictable benefits. These included protecting the reusable electronic module from defibrillation shocks (a known risk for patients requiring such monitoring), ensuring patient safety, and reducing the device's overall size by replacing bulky resistors, all of which were known goals in the field.
  • Expectation of Success: Petitioner asserted a POSITA would have a high expectation of success in this combination, as it would involve applying Kroll’s well-known screen-printing techniques for conductive inks onto the flexible substrate taught by Matsumura.

Ground 2: Obviousness over Matsumura, Kroll, and Ozguz - Claims 1, 2, 4, 5, 14, 15, and 43-45 are obvious over the combination of Matsumura, Kroll, and Ozguz.

• Prior Art Relied Upon: Matsumura, Kroll, and Ozguz (Application # 2005/0096513).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the combination of Matsumura and Kroll. Petitioner argued that while Matsumura disclosed the general concept of a signal processor, it did not specify a particular circuit design or architecture. Ozguz was argued to disclose a detailed architecture for a thin, flexible, self-contained bio-sensor module, including a microprocessor, transmitter, and an integral thin battery, that performs the same functions as the components in Matsumura.
  • Motivation to Combine: A POSITA would look to Ozguz to provide the specific circuit design, microprocessor, and power source details necessary to implement the functions broadly described in Matsumura. Incorporating Ozguz's compact, self-contained design would improve Matsumura’s device by making it more unobtrusive and reducing signal noise, which were key objectives for ambulatory monitors.
  • Expectation of Success: A POSITA would have a reasonable expectation of success in integrating Ozguz's circuit design into the Matsumura framework, as it involved applying known electronic design principles to achieve a more refined and functional version of the base device.

Ground 3: Obviousness over Matsumura, Ozguz, Kroll, and DeLuca - Claims 32-35 are obvious over the combination of Matsumura, Ozguz, Kroll, and DeLuca.

• Prior Art Relied Upon: Matsumura, Ozguz, Kroll, and DeLuca (Patent 6,238,338).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground addressed dependent claims directed to signal filtering. Petitioner argued that to implement Matsumura's function of detecting an "abnormal state" in an ECG, the raw analog signals must be processed. DeLuca taught a detailed "signal conditioning stage" for a biosignal monitor, including a high-pass filter with a selectable corner frequency, which is essential for accurately processing ECG data and is consistent with well-known algorithms like the Pan-Tompkins algorithm.
  • Motivation to Combine: A POSITA tasked with building the device in Matsumura would need to implement signal processing to make the device functional. The POSITA would combine DeLuca's specific and well-understood signal conditioning filters with the Matsumura/Ozguz/Kroll device to accurately detect heartbeats and identify abnormalities, thereby enabling the core functionality described in Matsumura.
  • Expectation of Success: The combination would be straightforward for a POSITA, as it involved implementing well-known signal filtering components and techniques on a microprocessor-based platform.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including a combination with Harland (a 2002 journal article) to teach the capacitive connections of claims 2 and 3, and a combination with Thompson (Patent 6,223,080) to teach the periodic low-power mode of claim 39.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §314(a), based on the Fintiv factors, would be inappropriate. The petition asserted that the co-pending parallel district court litigation was in its earliest stages, with no scheduling order entered or trial date set. Petitioner contended that neither the parties nor the court had invested substantial resources, and there was no overlap between the prior art and invalidity contentions in the petition and the issues in the parallel proceeding.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-6, 8, 10-15, 29, 31-35, 37-39, and 43-45 of the ’007 patent as unpatentable.