Double potential gradient analysis for critical isthmus detection in scar-related atrial tachycardia.

BACKGROUND

The presence of double potentials (DPs)-2 discrete electrogram deflections separated by an isoelectric segment-is a validated indicator during ablation of scar-mediated atrial tachycardia (AT). A corridor of parallel DPs is often used as a marker of a line of conduction block, whereby DP duration decreases as one approaches the conducting gap. In this context, it is the spatial gradient of DP duration that is used for isthmus localization. Here, we calculate the DP duration gradient of atrial electroanatomic maps and assess how it compares with DP duration as a quantitative metric in isthmus identification.

OBJECTIVE

The purpose of the study was to assess the utility of DP duration gradient for identifying AT isthmuses.

METHODS

Patients undergoing ablation of scar-mediated AT were included if a complete high-density map was available. Isthmus points were identified by an electrophysiologist before analysis. As point clouds from the electroanatomic maps are irregular, calculations of DP gradients were interpolated to a regular grid via inverse distance weighting. Gradients were then back-interpolated onto the original point clouds for analysis.

RESULTS

57 EAMs among 52 patients were available for analysis [13 (25.0%) female; median age 69.1 years]. Pooled isthmus points had higher DP gradient values than did nonisthmus points (Mann-Whitney, P < .001). In logistic regression, the DP gradient was more predictive of isthmus location than the DP duration (area under the curve 0.667; 95% confidence interval 0.660-0.673 vs area under the curve 0.621; 95% confidence interval 0.616-0.627; DeLong, P < .001.)

CONCLUSION

DP gradient is a more accurate predictor of isthmus points than DP duration, and may be useful in identifying its location.