iRhythm Inc v. Welch Allyn Inc

1. Case Identification

• Case #: IPR2025-00374
• Patent #: 8,965,492
• Filed: December 23, 2024
• Petitioner(s): iRhythm, Inc.
• Patent Owner(s): Welch Allyn, Inc.
• Challenged Claims: 1-8 and 11-14

2. Patent Overview

• Title: Body-Worn Patient Monitoring Device
• Brief Description: The ’492 patent discloses a body-worn physiological monitor designed for applications like electrocardiogram (ECG) monitoring. The invention’s key feature is the use of electrical traces made at least in part from a resistive material, intended to protect the device’s electronics from high-voltage events such as defibrillation, while eliminating the need for bulky conventional resistors. The device comprises two main components: a disposable electrode portion that adheres to the patient and a reusable communication and computation module that releasably attaches to the disposable portion.

3. Grounds for Unpatentability

Ground 1: Claims 1-3, 5-8, and 11-14 are obvious over Matsumura and Kroll.

• Prior Art Relied Upon: Matsumura (Japanese Patent Publication No. 2004/121360) and Kroll (Patent 4,763,660).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Matsumura disclosed all elements of the challenged claims except for the resistive traces. Matsumura taught a body-worn bioelectric potential detector with a disposable bioelectrode pad and a reusable signal processor. Kroll taught a flexible electrode belt with lead strips made from a flexible conductive ink compound with a preselected conductivity to serve as a current limiter, protecting the patient and device from electrical shock.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Kroll's resistive ink traces with Matsumura's wearable monitor for two primary reasons. First, it would provide a known solution to the well-understood problem of protecting sensitive monitor electronics from electrical overload, such as from a defibrillator. Second, incorporating Kroll’s ink-based resistive traces would align with the industry goal of device miniaturization by replacing the bulkier conventional resistors used in prior art monitors.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success, as the combination involved a minor modification to the materials used for printing electrical traces on Matsumura’s device, utilizing well-known screen-printing manufacturing techniques.

Ground 2: Claims 1-6 are obvious over Jensen and Kroll.

• Prior Art Relied Upon: Jensen (Application # 2003/0149349) and Kroll (Patent 4,763,660).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Jensen, which taught a body-worn physiological monitor in the form of a "smart patch" with a flexible circuit assembly, disclosed the core structure of independent claim 1. As in Ground 1, Kroll was relied upon to teach the limitation of making the electrical traces at least in part from a resistive material.
  • Motivation to Combine: The motivation was analogous to Ground 1. A POSITA would incorporate Kroll's resistive traces into Jensen's smart patch to provide necessary protection from electrical overload (e.g., defibrillation) and to further Jensen's stated goal of creating a thin, low-mass device by replacing conventional resistors with Kroll’s space-saving resistive ink traces.
  • Expectation of Success: Petitioner contended the combination would have been straightforward, involving a slight modification to the materials used to print traces on Jensen’s flexible circuit, with a predictable and successful outcome.

Ground 3: Claims 7, 8, and 11-14 are obvious over Jensen, Matsumura, and Kroll.

• Prior Art Relied Upon: Jensen (Application # 2003/0149349), Matsumura (Japanese Patent Publication No. 2004/121360), and Kroll (Patent 4,763,660).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground specifically targeted independent claim 7, which recites a disposable electrode portion and a separate, reusable communication module. Petitioner asserted that while Jensen disclosed a base device with disposable and reusable parts, Matsumura taught a superior hygienic and waterproof design that fully insulated the reusable electronics within a sealed housing, separate from the disposable, patient-contacting portion. Kroll, again, supplied the teaching of resistive traces.
  • Motivation to Combine: A POSITA would have been motivated to modify Jensen’s device with the teachings of Matsumura to improve hygiene and create a waterproof structure, allowing for continuous monitoring even during showering. This modification would involve reconfiguring Jensen’s components to match Matsumura’s separated disposable/reusable architecture. A POSITA would then incorporate Kroll's resistive traces into this improved design for the established reasons of electrical protection and size reduction.
  • Expectation of Success: Petitioner argued a POSITA would expect success in this combination, as it involved rearranging known components (electrodes, traces, processors) into a more effective, known configuration (Matsumura's hygienic design) to achieve predictable benefits.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial would be inappropriate.
• §314(a) (Fintiv): Petitioner contended that none of the Fintiv factors favored denial, asserting that a co-pending district court litigation was in its earliest stages, with no scheduling order entered and no significant investment of resources by the court or parties.
• §325(d): Petitioner argued against denial because the core prior art and arguments were not previously before the examiner. Kroll and Matsumura were never presented to the Office. While Jensen was cited in an Information Disclosure Statement, it was never substantively discussed or used as a basis for rejection, and the examiner never considered the specific combinations asserted in the petition, particularly the critical teaching of resistive traces from Kroll.

5. Relief Requested

• Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-8 and 11-14 of Patent 8,965,492 as unpatentable under 35 U.S.C. §103.