Signal Processing for Cardiac Applications

Novel approaches for mapping-specific rotor ablation in AF

AF is the most common sustained cardiac arrhythmia in humans, and is a prognostic marker for stroke, heart failure and even death. Recent animal and human research have shown that AF may also be maintained by rapid reentry sources (rotors), which can either be localized to a specific spatial location in the atria, or meander around the atria. Catheter ablation is one common treatment approach used to control AF, but it is associated with limited success rates in patients with persistent AF, which is mostly maintained by rotors that are located outside of the pulmonary veins (PV) regions. Currently existing commercial mapping systems cannot accurately identify the rotor location outside of the PV regions in patients with persistent AF. My lab developed several novel signal analysis approaches (multi-scale frequency, multiscale-entropy and Kurtosis) to identify the pivot points of rotors, and validated these approaches using optical mapping experiments in ex-vivo rabbit hearts, where electrical activity can be directly visualized. We also demonstrated that these techniques are accurate under some clinical limitations, such as reduced time duration of the signal and decreased spatial resolution. Further, these techniques can be used for different types of signals, including intracardiac electrograms (iEGMs). The translation of the techniques in clinical settings is important for the future of personalized therapy that will subsequently lead to successful diagnosis and treatment for, essentially, all other arrhythmias.

 

VIEgram: Visualization of clinical intracardiac electrograms on a patient-specific 3D heart model.

Visualization of intracardiac electrograms on 3D heart model (VIEgram) available from Technology Commercialization (umn.edu)

Currently, novel techniques for analyzing intracardiac electrograms (iEGMs) are being developed to identify the atrial fibrillation (AF) maintaining sites. Proprietary electroanatomical mapping systems used in clinics like CARTO (Biosense Webster), EnSite Precision (Abbott), etc., are used for mapping the results of the analysis on a patient's 3D heart model. The constrained access to these mapping systems has had been a hurdle in the development of novel techniques. The open-source platform is developed for mapping the results of the analysis on a patient's 3D heart model. It eliminates the dependency on the proprietary mapping systems thereby making the process of retrospective mapping extremely convenient and time-efficient for academic researchers. The developed software can be used for visual inspection of electrograms and implementing different techniques on extracted iEGM dataset. It allows performing region-wise analysis of atria. Also, CT/MRI based 3D heart model can be integrated with the generated 3D model to incorporate fibrosis and scar data. The ability to visualize novel approaches as 3D maps and their availability help in the development of spatial analysis techniques and region-specific monitoring of Human atria for academicians, thus providing a testing and validation capability prior to clinical implementation.