Motivated by the problem of verifying the correctness of arrhythmia-detection algorithms, we present a formalization of these algorithms in the language of Quantitative Regular Expressions. QREs are a flexible formal language for specifying complex numerical queries over data streams, with provable runtime and memory consumption guarantees. The medical-device algorithms of interest include peak detection (where a peak in a cardiac signal indicates a heartbeat) and various discriminators, each of which uses a feature of the cardiac signal to distinguish fatal from non-fatal arrhythmias. Expressing these algorithms{\textquoteright} desired output in current temporal logics, and implementing them via monitor synthesis, is cumbersome, error-prone, computationally expensive, and sometimes infeasible.
In contrast, we show that a range of peak detectors (in both the time and wavelet domains) and various discriminators at the heart of today{\textquoteright}s arrhythmia-detection devices are easily expressible in QREs. The fact that one formalism (QREs) is used to describe the desired end-to-end operation of an arrhythmia detector opens the way to formal analysis and rigorous testing of these detectors{\textquoteright} correctness and performance. Such analysis could alleviate the regulatory burden on device developers when modifying their algorithms. The performance of the peak-detection QREs is demonstrated by running them on real patient data, on which they yield results on par with those provided by a cardiologist.
}, year = {2017}, journal = {International Conference on Computational Methods in Systems Biology}, month = {09/2017}, publisher = {Springer, Cham}, address = {Darmstadt, Germany }, isbn = {978-3-319-67471-1}, doi = {https://doi.org/10.1007/978-3-319-67471-1_2}, language = {eng}, }