iRhythm Inc v. Welch Allyn Inc

1. Case Identification

• Case #: IPR2025-00377
• Patent #: 8,214,007
• Petitioner(s): iRhythm, Inc.
• Patent Owner(s): Welch Allyn, Inc.
• Challenged Claims: 1-8, 10-15, 29, 31-35, 37-39, and 43-45

2. Patent Overview

• Title: Body Worn Patient Monitor
• Brief Description: The ’007 patent describes a body-worn physiological monitor, such as for ECGs, comprising a disposable module with skin-contacting electrodes and a reusable, removable communication-computation module. The invention purports to solve the problem of protecting monitor electronics from defibrillation shocks by using "resistive traces" on a flexible substrate as current-limiting resistors, intended as a space-saving alternative to bulky prior art resistors.

3. Grounds for Unpatentability

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

• 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 disclosed all major components of the challenged claims, including a body-worn monitor with a disposable sensor assembly and a reusable electronic portion containing a microcontroller and transmitter. However, Jensen did not explicitly teach using resistive traces for circuit protection. Kroll, a reference directed to a disposable electrode belt, was argued to supply this missing element by teaching the use of lead strips made from a flexible conductive ink compound with a preselected conductivity to serve as a current limiter. The combination of Jensen's monitor architecture with Kroll's resistive trace technology allegedly rendered the claims obvious.
  • Motivation to Combine: Petitioner asserted two primary motivations. First, a POSITA would combine Kroll's teachings with Jensen's device to solve the known problem of protecting both the patient and the monitor's sensitive electronics from electrical overload, such as from a defibrillator. Second, a POSITA would be motivated to incorporate Kroll's ink-based resistive traces to reduce the size and improve the wearability of Jensen's monitor, a key design goal for such devices.
  • Expectation of Success: Petitioner contended that a POSITA would have a reasonable expectation of success, as implementing resistive ink traces using well-known screen-printing techniques on Jensen's flexible circuit would be a straightforward modification with minimal design impact.

Ground 2: Obviousness over Jensen, Kroll, and DeLuca - Claims 32-35 are obvious over the combination of Jensen, Kroll, and DeLuca.

• Prior Art Relied Upon: Jensen (Application # 2003/0149349), Kroll (Patent 4,763,660), and DeLuca (Patent 6,238,338).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the base combination of Jensen and Kroll to address dependent claims 32-35, which recite various signal filtering limitations (e.g., a high-pass filter with a selectable corner frequency). Petitioner argued that while Jensen taught basic filtering, DeLuca provided more specific teachings of a biosignal monitoring system with a "signal conditioning stage" that included high-pass, low-pass, and anti-aliasing filters to improve signal quality.
  • Motivation to Combine: A POSITA, seeking to improve the signal quality and reliability of the Jensen/Kroll device, would be motivated to incorporate the advanced, well-known signal conditioning techniques taught by DeLuca. Implementing such filtering was described as a standard step in algorithms for detecting heartbeats from ECG data.

Ground 3: Obviousness over Jensen, Kroll, and Harland - Claims 2 and 3 are obvious over the combination of Jensen, Kroll, and Harland.

• Prior Art Relied Upon: Jensen (Application # 2003/0149349), Kroll (Patent 4,763,660), and Harland (a 2001 journal article).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed claims 2 and 3, which require "indirect" or "capacitive" electrical connections to the body. Petitioner asserted that Harland taught an ultra-high impedance electric potential sensor that allowed for remote, non-contact detection of ECG signals by forming a capacitive coupling with the body.
  • Motivation to Combine: A POSITA would be motivated to modify the Jensen/Kroll device with Harland's capacitive sensors to address the known problem of skin irritation and allergies caused by the gels and adhesives used with direct-contact electrodes, particularly for devices intended for extended wear.

Ground 4: Obviousness over Jensen, Kroll, and Thompson - Claim 39 is obvious over the combination of Jensen, Kroll, and Thompson.

• Prior Art Relied Upon: Jensen (Application # 2003/0149349), Kroll (Patent 4,763,660), and Thompson (Patent 6,223,080).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground targeted claim 39, which recites an algorithm for entering a low-power mode between heartbeats (specifically, from the end of a T-wave to the beginning of the next P-wave). Petitioner argued that Thompson taught a processor for an implantable medical device that conserves power by operating in a high-speed mode only during the QRS complex and "idling along" at a lower clock frequency during the remainder of the cardiac cycle.
  • Motivation to Combine: A POSITA would have been motivated to incorporate a power-saving strategy like Thompson's into the battery-powered Jensen/Kroll device to prolong battery life, a critical design consideration for portable electronics.

4. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under both 35 U.S.C. §314(a) (Fintiv) and §325(d).
• Fintiv Factors: Petitioner asserted that the co-pending district court litigation was in its earliest stages, with no trial date set and minimal resources expended, weighing against denial.
• §325(d) Factors: Petitioner argued that denial under §325(d) was improper because, although Jensen was cited in an Information Disclosure Statement during prosecution, it was never substantively examined or used in a rejection. Furthermore, the key secondary references—Kroll, DeLuca, Harland, and Thompson—were never before the examiner. Petitioner contended the examiner’s art did not disclose the central "resistive trace" element taught by Kroll, making the asserted grounds novel and substantially different from those considered during prosecution.

5. Relief Requested

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