Automatic Identification of Reentry Mechanisms and Critical Sites During Atrial Tachycardia by Analyzing Areas of Activity.

Abstract

Atrial tachycardia(AT) still poses a major challenge in catheter ablation. Although state-of-the-art electroanatomical mapping systems allow to acquire several thousand intracardiac electrograms(EGMs), algorithms for diagnostic analysis are mainly limited to the amplitude of the signal (voltage map) and the local activation time(LAT map). We applied spatio-temporal analysis of EGM activity to generate maps indicating reentries and diastolic potentials, thus identifying and localizing the driving mechanism of AT. First, the time course of active surface areaASA is determined during one basic cycle length(BCL). The chamber cycle length coveragecCLC reflects the relative duration within one BCL for which activity was present in each individual atrium. A local cycle length coveragelCLC is computed for circular subareas with 20mm diameter. The simultaneous active surface areasASA is determined to indicate the spatial extent of depolarizing tissue. Combined analysis of these spatial scales allowed to correctly identify and localize the driving mechanism: cCLC values of 100% were indicative for atria harbouring a reentrant driver. lCLC could detect micro reentries within an area of 1.65 $\pm$ 1.28cm $^2$ in simulated data and differentiate them against focal sources. Middiastolic potentials, being potential targets for catheter ablation, were identified as areas showing confined activity based on sASA values. The concept of spatio-temporal activity analysis proved successful and correctly indicated the tachycardia mechanism in 20 simulated AT scenarios and three clinical data sets. Automatic interpretation of intracardiac mapping data could help to improve the treatment strategy in complex cases of AT.