Characterization of temporal electrical activity patterns for detection
of critical isthmus regions of recurrent atypical atrial flutter
Abstract
Introduction Identifying the critical isthmus region (CIR) of complex
atrial tachycardias (AT) is challenging. The Lumipoint® (LP) software,
developed for the Rhythmia® mapping system, aims to facilitate
successful termination of ATs by identifying the CIR. Objective
Objective of this study was to evaluate specificity and sensitivity of
LP regarding arrhythmia-relevant CIR detection in patients with
atypical-atrial-flutter (AAF). Methods In this retrospective analysis we
analyzed 57 AAF-forms. Electrical activity (EA) was mapped over
tachycardia cycle length resulting in 2-dimensional EA pattern. The
hypothesis was that an EA minimum suggests a potential CIR with
slow-conduction-zone. Results A total of n=33 patients were included.
LP-algorithm identified a mean of 2.4 EA minima and 4.4 suggested CIRs
per AAF-form. Overall, we observed a low specificity with 12.3% but a
high sensitivity of 98.2%. Detailed EA analysis revealed that depth
(≤20%) and width (>50ms) of EA minima were the best
predictors of relevant CIRs. Wide minima occurred rarely (17.5%), while
low minima were more frequently present (75.4%). Minima with a depth of
EA≤20% showed the best sensitivity and specificity overall (95% and
60%, respectively). Analysis in recurrent ablations in 5 patients
presenting de-novo AAF revealed that the CIR of de-novo AAF was already
detected by LP during the index procedure. Conclusion The LP algorithm
provides an excellent sensitivity (98.2%), but poor specificity
(12.3%) to detect the CIR in AAF. Specificity improved by preselection
of the lowest and widest EA minima. In addition, there might be role of
initial bystander CIRs becoming relevant for future AAFs