Method for Identifying Atrial Fibrillation and Flutter Held Patent Eligible

In Cardionet, LLC v. Infobionic, Inc.,¹ the U.S. Court of Appeals for the Federal Circuit held that a method for identifying atrial fibrillation and atrial flutter associated with stroke, congestive heart failure and cardiomyopathy was patent eligible. In holding that the claimed invention was not abstract, the court explained that there was no requirement for the court to evaluate prior art or facts outside the record to determine the state of the prior art. Judge Dyk concurred in the result, but dissented from the court by saying that the decision on patent eligibility should not be limited to the intrinsic record.

Cardionet-owned U.S. Patent 7,941,207 was directed to a method for identifying atrial fibrillation and atrial flutter associated with stroke, congestive heart failure and cardiomyopathy. The invention monitored heartbeat variability and identified irregular ventricular beats. The invention utilized off-the-shelf technology to measure heartbeat activity and already-existing logic for determining heartbeat variability. The novel feature was the claimed relevance determination logic that identified the relevance of the variability in the beat-to-beat timing with respect to atrial fibrillation or atrial flutter, and an event generator that triggered when variability was relevant. Claim 1 recited the following:

1. A device, comprising:

a beat detector to identify a beat-to-beat timing of cardiac activity;

a ventricular beat detector to identify ventricular beats in the cardiac activity;

variability determination logic to determine a variability in the beat-to-beat timing of a collection of beats;

relevance determination logic to identify a relevance of the variability in the beat-to-beat timing to at least one of atrial fibrillation and atrial flutter; and

an event generator to generate an event when the variability in the beat-to-beat timing is identified as relevant to the at least one of atrial fibrillation and atrial flutter in light of the variability in the beat-to-beat timing caused by ventricular beats identified by the ventricular beat detector.

The Federal Circuit reasoned that claim 1 was not abstract:

When read as a whole, and in light of the written description, we conclude that claim 1 of the ’207 patent is directed to an improved cardiac monitoring device and not to an abstract idea. In particular, the language of claim 1 indicates that it is directed to a device that detects beat-to-beat timing of cardiac activity, detects premature ventricular beats, and determines the relevance of the beat-to-beat timing to atrial fibrillation or atrial flutter, taking into account the variability in the beat-to-beat timing caused by premature ventricular beats identified by the device’s ventricular beat detector. In our view, the claims focus on a specific means or method that improves cardiac monitoring technology; they are not directed to a result or effect that itself is the abstract idea and merely invoke generic processes and machinery.

The court also noted that the written description supported the advantages of the invention, including that it more accurately detected the atrial fibrillation or flutter:

[H]ere, the ’207 patent’s written description identifies a number of advantages gained by the elements recited in the claimed cardiac monitoring device. By analyzing the “variability in the beat-to-beat timing” for “atrial fibrillation and atrial flutter in light of the variability in the beat-to-beat timing caused by ventricular beats identified by the ventricular beat detector,” the claimed invention more accurately detects the occurrence of atrial fibrillation and atrial flutter, as distinct from V-TACH and other arrhythmias. . . . We accept those statements as true and consider them important in our determination that the claims are drawn to a technological improvement.

The court also explained that there was no suggestion in the ’207 patent specification that the invention was not novel:

Nothing in the record in this case suggests that the claims merely computerize pre-existing techniques for diagnosing atrial fibrillation and atrial flutter. Moreover, . . . the written description of the ’207 patent confirms that the asserted claims are directed to a specific technological improvement—an improved medical device that achieves speedier, more accurate, and clinically significant detection of two specific medical conditions out of a host of possible heart conditions.

Therefore, the court held that the claimed invention was not abstract and therefore was patent eligible. Since the claimed invention was not abstract, the court also held that it was not necessary to determine whether the elements of each claim both individually and as an ordered combination transformed the nature of the claim into a patent-eligible application.

Why Is Cardionet Important?

The court’s decision holds that the claimed method for identifying atrial fibrillation and flutter was patent eligible because it more accurately detected the occurrence of atrial fibrillation and flutter. Significantly, the invention utilized off-the-shelf technology to measure heartbeat activity and already-existing logic for determining heartbeat variability. The novel feature was the claimed relevance determination logic, which was a new functionality. In holding that the claimed invention was not abstract, the court explained that there was no requirement to evaluate prior art or facts outside the record to determine the state of the prior art. However, the court did not prohibit reviewing the state of the prior art, and in most cases a review of the state of the prior art is likely. Expect the issue of when a court can or should review the state of the prior art when deciding patent-eligibility matters to continue.

_{¹ Cardionet, LLC v. Infobionic, Inc., 955 F.3d 1358, 2020 USPQ2d 10367, 2020 WL 1897237 (Fed. Cir. 2020).}