PT  - JOURNAL ARTICLE
AU  - Desmond Kabus
AU  - Louise Arno
AU  - Lore Leenknegt
AU  - Alexander V. Panfilov
AU  - Hans Dierckx
TI  - Numerical methods for the detection of phase defect structures in excitable media
AID  - 10.1101/2021.12.16.473086
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2021.12.16.473086
4099  - http://biorxiv.org/content/early/2022/01/07/2021.12.16.473086.short
4100  - http://biorxiv.org/content/early/2022/01/07/2021.12.16.473086.full
AB  - Electrical waves that rotate in the heart organize dangerous cardiac arrhythmias. Finding the region around which such rotation occurs is one of the most important practical questions for arrhythmia management. For many years, the main method for finding such regions was so-called phase mapping, in which a continuous phase was assigned to points in the heart based on their excitation status and defining the rotation region as a point of phase singularity. Recent analysis, however, showed that in many rotation regimes there exist phase discontinuities and the region of rotation must be defined not as a point of phase singularity, but as a phase defect line. In this paper we use this novel methodology and perform comparative study of three different phase definitions applied to in-silico data and to experimental data obtained from optical voltage mapping experiments on monolayers of human atrial myocytes. We introduce new phase defect detection algorithms and compare them with those that appeared in literature already. We find that the phase definition is more important than the algorithm to identify sudden spatial phase variations. Sharp phase defect lines can be obtained from a phase derived from local activation times observed during one cycle of arrhythmia. Alternatively, similar quality can be obtained from a reparameterization of the classical phase obtained from observation of a single timeframe of transmembrane potential. We found that the phase defect line length was (35.9 ± 6.2) mm in the Fenton-Karma model and (4.01 ± 0.55) mm in cardiac human atrial myocyte monolayers. As local activation times are obtained during standard clinical cardiac mapping, the methods are also suitable to be applied to clinical datasets. All studied methods are publicly available and can be downloaded from an institutional web-server.Competing Interest StatementThe authors have declared no competing interest.