![bipolar square wave with eak amplitude bipolar square wave with eak amplitude](https://e2e.ti.com/resized-image/__size/320x240/__key/communityserver-discussions-components-files/14/pastedimage1628606089362v1.png)
Given three EGMs, a local CV vector describing the speed and direction of wavefront propagation can be “triangulated” in this way ( Dubois et al., 2012 Cantwell et al., 2015 Verma et al., 2016, 2018 Zheng et al., 2017 Anter et al.,2018a,b). Most commonly, CV is calculated using the local activation time (LAT) differences and spatial separation of sets of recorded EGMs (the time to cover a known distance defines speed). There are multiple methods to calculate CV ( Cantwell et al., 2015 Masse et al., 2016).
![bipolar square wave with eak amplitude bipolar square wave with eak amplitude](https://www.biorxiv.org/content/biorxiv/early/2019/10/05/793729/F2.large.jpg)
Fundamental electrodynamic ( King et al., 2013) and clinical studies ( Brunckhorst, 2002 Jaïs et al., 2012 Nayyar et al., 2014 Irie et al., 2015 Jackson et al., 2015 Anter et al., 2016, 2018a,b) have suggested that areas of slow conduction velocity (CV) are likely to be pro-arrhythmic. Our computational modeling and clinical results suggest this relationship can be leveraged clinically to improve measurement accuracy for small LAT differences, which may improve CV measurement at small spatial scales.Ĭardiac arrhythmia results from a complex interplay of fixed anatomical and dynamic functional sources that are often times difficult to characterize clinically. These results demonstrate an underlying relationship between a bipolar EGM’s peak amplitude and the activation time difference between its two electrodes. Using clinical EGMs, there was agreement in LAT differences found by DELTA, standard LAT annotation, and unipolar waveform cross-correlation. Finally, we validated the DELTA method in vivo using 18,740 bipolar EGMs recorded from the left atrium of 10 atrial fibrillation patients undergoing catheter ablation. DELTA-derived LAT differences were more accurate than standard LAT annotation in simulated complex fractionated EGMs from a model incorporating fibrosis. In a 1-dimensional and a 2-dimension model, CV calculations were more accurate using LAT differences found by the DELTA method than by standard LAT annotation (by unipolar dV/dt timing). With 1 kHz sampling, LAT differences less than 4 ms were more accurately measured with DELTA than by standard LAT annotation (mean error 3.8% vs. Next, we use simulated EGMs from a computational model to validate this method. This allows LAT differences to be calculated from bipolar EGM peak amplitude, by a novel “Determination of EGM Latencies by Transformation of Amplitude” (DELTA) method. First, we use a simplified theoretical model to identify a quantitative relationship between the LAT difference of a pair of electrodes and the peak amplitude of the bipolar EGM measured between them. We sought to develop a method for high-resolution measurement of LAT differences and validate against existing techniques. This is in part because measurement of local CV at small spatial scales (1 mm) requires accurate annotation of local activation time (LAT) differences with very high temporal resolution (≤1 ms), beyond that of standard clinical methods. Localized changes in myocardial conduction velocity (CV) are pro-arrhythmic, but high-resolution mapping of local CV is not yet possible during clinical electrophysiology procedures.