iRhythm Technologies Inc v. Welch Allyn Inc

1. Case Identification

• Case #: IPR2025-01081
• Patent #: 8,630,699
• Filed: June 3, 2025
• Petitioner(s): iRhythm Technologies, Inc.
• Patent Owner(s): Welch Allyn, Inc.
• Challenged Claims: 1-4 and 8

2. Patent Overview

• Title: Wearable ECG Monitor with Defibrillation Protection
• Brief Description: The ’699 patent discloses a body-worn electrocardiogram (ECG) monitor designed for patient comfort and durability. Its key feature is the use of a current-limiting defibrillation protection resistor that is screen-printed directly onto a flexible substrate, which protects the device’s sensitive electronics from high-energy shocks during defibrillation without requiring bulky, conventional resistor components.

3. Grounds for Unpatentability

Ground 1: Obviousness over Jensen and Kroll - Claims 1-4 are obvious over Jensen in view of Kroll and the general knowledge of a POSITA.

• 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 a flexible, wearable ECG monitor (a “smart patch”) with all the basic components of claim 1 except for a screen-printed defibrillation resistor. Kroll was asserted to cure this deficiency by teaching a flexible electrode belt with current-limiting lead strips made from a "flexible conductive ink compound" that is "silk screened" onto a substrate. The combination of Jensen's monitor with Kroll's screen-printed resistive traces allegedly rendered all limitations of independent claim 1 obvious. The dependent claims were argued to be obvious because Jensen and Kroll both teach flexible substrates (claim 2), and Jensen’s sensor contacts provide a mechanical interface that is inherently filleted and layered (claims 3 and 4).
  • Motivation to Combine: A POSITA would combine Jensen and Kroll for two primary reasons. First, to add necessary defibrillation protection to Jensen’s medical-grade monitor to ensure it complied with known industry standards and protect the device electronics, a problem Kroll expressly solved. Second, using Kroll’s screen-printed resistor aligned with Jensen’s stated goal of creating a thin, low-mass device, as it would be a more compact solution than using conventional, bulky resistors.
  • Expectation of Success: Petitioner asserted a POSITA would have a reasonable expectation of success, as the combination involved applying a well-known manufacturing technique (screen-printing resistive ink, per Kroll) to a known device architecture (a flexible ECG monitor, per Jensen).

Ground 2: Obviousness over Jensen, Kroll, and Thompson - Claim 8 is obvious over Jensen in view of 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 built upon the combination of Jensen and Kroll for the limitations of claim 1 and added Thompson to teach the specific low-power mode recited in claim 8. Petitioner contended that Jensen disclosed a microcontroller for processing heartbeat signals. Thompson was argued to teach a method for power conservation in a medical device by operating its processor in a high-speed mode only during the QRS complex of the cardiac cycle and in a low-power "idling" mode during the remainder of the cycle. This period of idling was argued to encompass the period recited in claim 8 (from the end of a T-wave to the beginning of the next P-wave).
  • Motivation to Combine: A POSITA would be motivated to improve the limited battery life of Jensen's battery-powered wearable device. Thompson provided a known technique for optimizing power consumption by implementing a periodic low-power mode tied to the cardiac cycle, which directly addressed this well-understood design constraint.
  • Expectation of Success: Success was expected without undue experimentation because implementing the low-power mode would primarily involve reprogramming the onboard software of Jensen’s microcontroller, a routine task for a POSITA.

Ground 3: Obviousness over Matsumura and Kroll - Claims 1, 2, and 4 are obvious over Matsumura in view of Kroll and the general knowledge of a POSITA.

• 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 this combination was analogous to Ground 1, but with Matsumura serving as the primary reference. Matsumura was asserted to disclose a wearable, flexible "bioelectric potential detector" for monitoring ECG signals. As in Ground 1, Kroll supplied the teaching of screen-printed, current-limiting resistive traces. The combination allegedly met all limitations of claim 1.
  • Motivation to Combine: A POSITA would be motivated to incorporate Kroll’s teachings to ensure Matsumura’s medical-grade device could survive defibrillation, a known requirement. Matsumura’s disclosure that its device alerts medical staff to a "sudden change in condition" would suggest to a POSITA that defibrillation is a foreseeable event for the patient, making such protection necessary. Kroll’s compact, screen-printed solution was well-suited to Matsumura's flexible device.
  • Expectation of Success: The combination was asserted to be straightforward, as it involved using well-known screen-printing techniques on a flexible substrate, a method disclosed in both references.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including claim 3 over Matsumura, Kroll, and Khandpur (for teaching a filleted "tear-like" edge to improve connection reliability) and claim 8 over Matsumura, Kroll, and Thompson (for adding a low-power mode to the Matsumura-based device).

4. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under both §314(a) (Fintiv) and §325(d).
• Under Fintiv, Petitioner contended that the parallel district court litigation was in its nascent stages, with a trial not scheduled until March 2027. The ’699 patent was only recently added to the litigation, and the petition was filed promptly thereafter.
• Under §325(d), Petitioner argued that while Jensen was cited in an Information Disclosure Statement during prosecution, it was never substantively examined by the USPTO. Furthermore, the proposed combinations with Kroll and Thompson are entirely new and were never before the Examiner, who allowed the patent based on distinguishing prior art from a different technical field.

5. Relief Requested

• Petitioner requests institution of inter partes review and cancellation of claims 1-4 and 8 of the ’699 patent as unpatentable.