A phase defect framework for the analysis of cardiac arrhythmia patterns

TL;DR

This paper introduces a new framework based on phase defect lines and surfaces for analyzing cardiac arrhythmia patterns, offering a more general approach than traditional phase singularity methods, with applications demonstrated on experimental data.

Contribution

The paper proposes a phase defect line and surface framework that unifies local activation time and phase descriptions, improving analysis of cardiac arrhythmias over existing methods.

Findings

Nearly all phase singularities were on phase defect lines.

Phase defect lines had longer lifespans than phase singularities.

Framework applied successfully to simulation and experimental data.

Abstract

During cardiac arrhythmias, dynamical patterns of electrical activation form and evolve, which are of interest to understand and cure heart rhythm disorders. The analysis of these patterns is commonly performed by calculating the local activation phase and searching for phase singularities (PSs), i.e. points around which all phases are present. Here we propose an alternative framework, which focuses on phase defect lines (PDLs) and surfaces (PDSs) as more general mechanisms, which include PSs as a specific case. The proposed framework enables two conceptual unifications: between the local activation time and phase description, and between conduction block lines and the central regions of linear-core rotors. A simple PDL detection method is proposed and applied to data from simulations and optical mapping experiments. Our analysis of ventricular tachycardia in rabbit hearts $(n=6)$ shows that nearly all detected PSs were found on PDLs, but the PDLs had a significantly longer lifespan than the detected PSs. Since the proposed framework revisits basic building blocks of cardiac activation patterns, it can become a useful tool for further theory development and experimental analysis.