3D Map Interpretation – 5

This is a PA view of the left atrium. We are observing the posterior wall and pulmonary veins, the left atrial appendage is also able to be seen.

Propagation Map:

In this same view, you may visualize the wave of depolarization traveling down the posterior wall. This was acquired with the AcQmap system by Acutus and it’s dipole density technology. 

“Non-contact, global, dipole density mapping partly obviates the technical skill needed for high-density contact mapping. Dipole density derives the local charge sources on the surface from intracavitary voltage, an approach that should minimize far-field effects.

 The AcQMap system (Acutus Medical Inc) employs a basket catheter [25 mm diameter, 48 ultrasound transducers (m- mode), 48 engineered electrodes] that rapidly acquires i) endocardial ultrasound distances to render 3D left atrial anatomy, and ii) bio-potential data for rapid far-field mapping. An inverse solution is used to calculate the dipole density from the voltages measured on the basket. The calculated data is spatially and temporally applied to the final processed surface anatomy as either a depolarization or propagation history map. In a depolarization map, the red region depicts the negative phase of dipole density and when animated is associated with the propagation of depolarization. In the propagation history map, red represents the leading edge of the activation wavefront with the trailing color bands showing earlier locations of the wavefront.”

https://www.acutusmedical.com/media/Poster-Acutus-HRS-2016_Final.pdf

“The system can detect and display both the standard voltage-based maps as well as the higher resolution dipole density maps. The result of combining highly accurate imaging with higher resolution mapping capabilities enables EP’s to identify and locate the responsible tissue for the irregular heart rhythm, target treatment with pinpoint accuracy, and minimize heart ablation.”

https://www.dicardiology.com/article/dipole-density-offers-advantages-over-standard-voltage-mapping-atrial-flutter-patients

This link will bring you to an animation of the acquisition of dipole signals. https://youtu.be/OOtGvM3n3Do 

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For more information:  EP Essentials – Understanding EP: A Comprehensive Approach