An international research team, led by the EP Analytics LAB group at ITACA-UPV, has developed a new quantitative framework to reformulate the concept of high density applied to precision cardiac electrophysiological mapping, a key tool for the diagnosis and treatment of complex arrhythmias.

The study, published in the journal Computers in Biology and Medicine and developed together with researchers from University College London, ETH Zürich and the University of Graz, addresses a fundamental limitation of this technology: the failure, in real clinical environments, to meet the theoretical assumptions on which high-density electrophysiological analysis with commercially available multielectrode catheters is based.

In this regard, high-density cardiac mapping is an advanced technology that enables analysis of the heart’s electrical activity by capturing multiple signals with a small catheter.

“This makes it possible to characterize with great accuracy the properties of the local electrophysiological substrate and thus identify abnormal regions. To do so, it assumes that propagation between neighboring electrodes is flat and uniform, which is not necessarily the case at a distance of 4 mm between them”, explains Elisa Ramírez, lead author of the article and researcher at ITACA.

However, Elisa notes that factors such as electrode spacing, the anatomical complexity of the heart, or damaged or fibrotic tissue “can alter signal reconstruction and reduce the level of detail in electroanatomical maps, in a similar way to when we reduce the pixel density of an image.”

Work developed

For these reasons, a quantitative framework is proposed that has made it possible, for the first time, to coin the term ultra-high resolution, understood as the level of resolution sufficient to capture, with the highest possible level of detail, all the complexity of the heart’s electrical activity, even in the most heterogeneous areas, where the keys to the genesis and perpetuation of arrhythmias are usually found.

To this end, a systematic study was designed using simulations based on advanced mathematical models and real high-density electrograms obtained from clinical cases. The study involved a multidisciplinary team made up of researchers from prestigious institutions such as ETH Zürich, Imperial College London and Graz Medical University.

Main results

As a result of the study, it was concluded that the highest definition was achieved with an electrode spacing of 0.5 mm, much smaller than the 4 mm of the Advisor™ HD Grid catheter, the reference device in clinical practice.

“The results indicate that an electrode spacing of around 0.5 mm marks that practical limit: below that distance, further improvements are already very small”, states Francisco Castells, co-head of the EP Analytics group and co-author of the research.

In addition, the researchers observed that although such small separations are not currently achievable in practice due to technological limitations, it would be possible to achieve ultra-high resolution by interpolating the electric field and thus creating virtual electrodes with a much higher density than the original catheter.

“Interpolation makes it possible to increase spatial resolution and obtain much more reliable signals, with lower errors and a high correlation with the reference signals”, explains José Millet, head of the EP Analytics LAB group and co-author of the research.

Furthermore, as Raúl Alós, co-author of the work, points out: “This improvement can be achieved without the need to modify the hardware, allowing greater compatibility with existing devices”.

Conclusion and value of the study

Overall, the study introduces the concept of ultra-high resolution, defined as the minimum resolution required for the electrophysiological assumptions underlying high-density cardiac mapping to be robustly met. In this way, the work demonstrates that accurate omnipolar mapping requires a spatial resolution higher than that provided by current techniques, yet it is possible to achieve this without altering clinical hardware.

“Thanks to this systematic study, we have been able to understand the limitations of this technology and, with that, establish minimum criteria to preserve all relevant information, providing a practical and effective solution», explain ITACA researchers.

Finally, José Millet highlights the medium- and long-term impact of the study, as it establishes a benchmark for future catheter design and the development of new signal-processing techniques.

“Future generations of high-density catheters, together with advanced processing methods, will provide specialist physicians with higher-definition visualization, which will undoubtedly facilitate a more precise and personalized diagnosis of the underlying mechanism of arrhythmia”, he concludes.

Reference:

Elisa Ramírez, Raul Alós, Johanna Tonko, Samuel Ruipérez-Campillo, Matthias A.F. Gsell, Gernot Plank, Pier Lambiase, José Millet, Francisco Castells (2025).
Ultra-high resolution for accurate analysis in cardiac mapping: a path towards fulfillment of assumptions in omnipolar technology. Computers in Biology and Medicine.

DOI: https://www.sciencedirect.com/science/article/abs/pii/S0010482525017536?via%3Dihub