Abstract
Purpose: Ablation of the pathway responsible of the maintenance of the reentry during atrial flutter (AFL) is a widely used therapy to terminate the arrhythmia. However, identification of the AFL pathway may be complex in atypical circuits. The aim of this study is to illustrate the potential non-invasive identification of the reentrant propagations in the atria with body surface potential mapping (BSPM).
Method: Segments of atrial activity recorded with 67 unipolar leads distributed in the torso in nine patients with either typical (N=3) or atypical (N=6) AFL were studied. Instantaneous phase maps were computed by using the phase of the Hilbert transform on surface ECGs. A phase singularity (PS) was defined as a point surrounded by all the phases from pi to pi. Occurrence maps of PS were computed for each patient.
Results: Phase maps of typical (Panel A) and atypical (Panel B) AFLs present rotational patterns with distinct location of PS. Occurrence maps of typical AFL patients present clustered PSs whereas PSs in atypical AFL patients are more scattered and do not match with typical AFL locations (Panel C).
Conclusion: Atypical and typical AFL can be discriminated by using BSPM and PS detection. Typical AFL presents clustered PS locations near the axillary lines that are consistently found in different patients. Atypical AFL PS locations are scattered and do not match with typical AFL locations. The reentrant circuits responsible of AFL can be potentially detected non-invasively by phase analysis of BSPM recordings.
