Background
CardioNet, LLC holds patents on ambulatory cardiac monitoring technology — systems that continuously monitor a patient’s heart rhythm remotely and detect arrhythmias. An earlier Federal Circuit decision in a related CardioNet case had upheld similar claims as patent-eligible under § 101 because they were specifically directed to a technological improvement in detecting atrial fibrillation and flutter.
In this second CardioNet case, InfoBionic, Inc. challenged a different set of claims from the same patent family. The disputed claim was directed to a cardiac monitoring system that detects heartbeat variability, measures T-wave data, and filters out T-wave signals that might otherwise be confused with atrial fibrillation. InfoBionic moved for summary judgment, arguing the claim was invalid under § 101 as directed to an abstract idea — specifically, the abstract idea of filtering data. The District of Massachusetts agreed and invalidated the claim. CardioNet appealed.
The Court’s Holding
The Federal Circuit affirmed. Writing for the court, Judge Reyna held that the disputed claim was directed to the abstract idea of filtering data — a step removed from the more specific, technological claim language that had saved CardioNet’s earlier patent in the prior Federal Circuit decision. The critical distinction: the earlier claim described specific hardware arrangements and a specific technical problem with cardiac monitoring equipment, while this claim described filtering at a higher level of generality without reciting a specific technical solution or improvement to the monitoring technology itself.
At Alice step two, the court found no inventive concept. The filtering function performed by the claim was a generic data processing step applied to cardiac data — the kind of routine data manipulation that existing monitoring systems could perform without the specific configuration that made earlier CardioNet claims eligible. Because the combination of elements added nothing inventive beyond applying the abstract filtering idea to cardiac monitoring data, the claim was invalid.
Key Takeaways
- The patent eligibility of cardiac monitoring claims turns on specificity: claims directed to specific hardware configurations or technical improvements in the monitoring process have a better § 101 track record than claims directed to generic data filtering or analysis steps applied to cardiac signals.
- Even within a patent family where some claims have survived § 101 challenges, other claims may fail if they are drafted at a higher level of generality that abstracts away from the specific technical improvement.
- Data filtering — even when applied to medically significant signals like cardiac rhythms — remains at risk under Alice step one as an abstract idea without a specific technical implementation that improves the technology itself.
- Medical device patent prosecutors should ensure that eligibility-sensitive claims recite specific hardware arrangements, physical configurations, or concrete technical improvements rather than purely functional data processing steps.
Why It Matters
CardioNet v. InfoBionic illustrates the fine line between patent-eligible and ineligible medical technology claims under the Alice/Mayo framework. Two claims from the same patent family can receive different results based on how specifically each claim ties its function to a concrete technical solution. For the medical device and digital health industries — where patents frequently describe sophisticated monitoring, filtering, and analysis of physiological data — this decision is a reminder that abstract data processing steps do not become eligible merely because they are applied to medically important information.
The contrast with the earlier CardioNet decision in the same patent family makes the case especially useful as a teaching example: draft claims to recite the specific technical configuration that solves the problem, not just the functional outcome. Claim drafters in the digital health space should anchor their claims to specific hardware arrangements, sensor configurations, or algorithmic implementations that constitute genuine improvements to the monitoring or diagnostic technology — not just the observation or filtering of physiological data.