Novel Algorithmic Methods in Mapping of Atrial and Ventricular Tachycardia
Background—Conventional methods to assess local activation time (LAT) detect the peak of the bipolar electrogram (B-EGM, B-LATPeak) or the maximal negative slope of the unipolar electrogram (U-EGM, U-LATSlope). We evaluated three novel methods to assess LAT: onset (B-LATOnset) and center of mass (B-LATCoM) of B-EGM, and maximal negative slope of U-EGM within a predefined bipolar window (U-LATSlope-hybrid).
Methods and Results—In 1,753 AT and 1,426 VT recordings, the performance of the methods in detecting LAT was evaluated paired-wise (e.g. B-LATPeak vs. B-LATOnset). For each comparison, histogram analysis of the differences in LAT values was performed. Variation in differences (P95-P5) in low quality (LQ) was compared to high quality (HQ) EGMs. In a separate dataset (12 AT and 10 VT) we evaluated for each method the accuracy in algorithmic activation mapping. Both in AT and VT, the variation in difference between the conventional and the novel methods was larger in LQ EGMs. In contrast, variation in difference between the novel methods was comparable in LQ and HQ EGMs. Except for LATSlope-hybrid, all methods showed decreased mapping accuracy with increasing percentage of LQ EGMs. U-LATSlope-hybrid accurately mapped activation in 16 out of 22 maps (vs. B-LATCoM, 14; B-LATPeak, 14; B-LATOnset, 13; U-LATSlope, 4).
Conclusions—In LQ atrial and ventricular electrograms, the novel LAT methods (B-LATOnset, B-LATCoM, and U-LATSlope-hybrid) show less variation than the conventional methods. The U-LATSlope hybrid -a hybrid method which accurately detects the maximal negative unipolar slope- is associated with the highest accuracy in algorithmic mapping of AT/VT.
- Received July 10, 2013.
- Revision received March 18, 2014.
- Accepted April 6, 2014.