Research Overview

The mechanical contractions of the heart are triggered by electrical waves of excitation propagating through cardiac tissue. Abnormalities in the wave propagation, including fast and chaotic propagation in the heart, may lead to fatal cardiac arrhythmias, such as ventricular fibrillation (VF) and atrial fibrillation (AF).

The general goal of Dr. Talkachova’s group is to investigate the electrical activity of the whole heart from a nonlinear dynamics perspective, aiming to reveal mechanisms of complex cardiac rhythms leading to VF and AF.

We use high resolution optical mapping technique to record electrical activity from the ex-vivo hearts, as well as small patches of stem cells, with the help of voltage- and calcium-sensitive dyes. Analysis of complex spatio-temporal dynamics of the electrical and mechanical activity in the heart helps us to develop techniques for prediction and control of cardiac arrhythmias.

In one of our projects, we develop anti-arrhythmic pacing protocols that can improve the pacing modality of the heart and prevent it from going into VF. In another project, we are developing new signal processing techniques to identify the sources of electrical turbulence during AF. These techniques are to be used for guiding clinicians who perform mapping-specific AF ablation in patients.

Finally, we are interested in investigating the therapeutic potential of neuromodulation, specifically, vagal nerve stimulation, for treatment of cardiovascular diseases and hypertension.

Education

• BS, Physics, Belarussian State University, Minsk, Belarus, 1991
• MS, Physics, Belarussian State University, Minsk, Belarus, 1992
• PhD, Nonlinear optics and laser physics, Nice University, Nice France, 2003

Selected Publications

1.     Ravikumar V, Annoni E, Parthiban P, Zlochiver Sh, Roukoz H, Mulpuru SK, Tolkacheva EG, “Novel mapping techniques for rotor core detection using simulated intracardiac electro grams”, J Cardiovasc Electrophysiol. 2021;1–13., DOI: 10.1111/jce.14948

2.     S. Newell, P. Parthiban  and E.G. Tolkacheva, Effect of constant DI pacing and Voltage-Calcium coupling on bifurcation in cardiac cell. Chaos, 30, 103122 (2020); doi: 10.1063/5.0022066

3.     S. Thakare, J. Mathew, S. Zlochiver, X. Zhao, E.G. Tolkacheva. Global versus local control of Cardiac Alternans in a 1D Numerical Model of Human Ventricular Tissue, Chaos, 30, 083123 (2020); DOI: 10.1063/5.0005432

4.     Jieun Lee, Yugene Guo, Vasanth Ravikumar, and E.G. Tolkacheva. “Towards development of approaches to discriminate AF from NSR using a Single-Lead ECG”, Entropy, 2020, 22, 531; doi:10.3390/e22050531

5.     Molly E. Kupfer, Wei-Han Lin, Vasanth Ravikumar, Ling Gao, Megan Lenz, Didarul Bhuiyan, Jeffrey Ai, DeWayne Townsend, Jianyi Zhang, Elena G. Tolkacheva, and Brenda M. Ogle. “In situ expansion, differentiation and electromechanical coupling of human cardiac muscle in a 3D bioprinted, chambered organoid”, Circ Res. 2020 Mar 31. doi: 10.1161/CIRCRESAHA.119.316155. Best manuscript award, 2020

6.     Special Issue on Nonlinear and Computational Dynamics in Biomedical Applications, Elena G. Tolkacheva, Brian Feeny, Xiaopeng Zhao, Journal of Computational and Nonlinear Dynamics, 2019

7.     Ning Wei, Elena G. Tolkacheva Interplay between ephaptic coupling and complex geometry of myocardial infarction border zone: effect on arrhythmogeneity Chaos. 2020 Mar; 30 (3):033111. doi: 10.1063/1.5134447.

8.     E.M. Annoni, D.Van Helden, Y. Guo, B. Levac, I. Libbus, B.H. KenKnight, J.W. Osborn, E.G. Tolkacheva. “Chronic low-level vagus nerve stimulation improves long-term survival in salt-sensitive hypertensive rats”, Frontiers of Physiology, 10:25. doi: 10.3389/fphys.2019.000252019

9.     S. W. Lee*, A. Anderson*, P. A. Guzman, A. Nakano, E. G. Tolkacheva*, K. Wickman*, “Atrial GIRK channels mediate the effects of vagus nerve stimulation on heart rate dynamics and arrhythmogenesis”, Front Physiol. 2018 Jul 19;9:943. doi: 10.3389/fphys.2018.00943. *co-corresponding authors, equal contribution

11.  S.W. Lee, K. Kulkarni, E.M. Annoni, I. Libbus, B.H. KenKnight, E.G. Tolkacheva, “Stochastic vagus nerve stimulation affects acute heart rate dynamics in rats, PLOS ONE, 2018. doi: 10.1371/journal.pone.0194910.

12.  K. Kulkarni, S.W. Lee, R. Kluck, E.G. Tolkacheva, “Real-Time Closed Loop Diastolic Interval Control Prevents Cardiac Alternans in Isolated Whole Rabbit Hearts, Annals of BME, 46(4), 555-566, 2018. DOI: 10.1007/s10439-018-1981-2

13.  K. Kulkarni, X. Xie, E.M.F. de Velasco, N. Carlblom, K. Wickman, E.G. Tolkacheva, The influences of the M2R-GIRK4-RGS6 dependent parasympathetic pathway on electrophysiological properties of the mouse heart, PLOS ONE, 2018; doi: 10.1371/journal.pone.0193798

14.  A. Anderson, K. Kulkarni, E.M. F. de Velasco, N. Carlblom, Z. Xia, X. Xie, A. Nakano, K. Martemyanov, E. G. Tolkacheva, Kevin Wickman, Expression and relevance of the G protein-gated K⁺ channel in the mouse ventricle, Scientific Reports, 2018.  doi: 10.1038/s41598-018-19719-x.

15.  Arunachalam SP, Kapa S, Mulpuru KS, Friedman PA, Tolkacheva EG, Improved Multiscale Entropy Technique with Nearest-Neighbor Moving Average Kernel for Non-Linear and Non-stationary Short Time Biomedical Signal Analysis, Journal of Healthcare Engineering, 2017. DOI: 10.1155/2018/8632436

16.  Annoni E.M., Arunachalam S.P., Suraj K., Mulpuru S.K., Friedman P.A., Tolkacheva E.G. Novel quantitative analytical approaches for rotor identification and associated implications for mapping, 2017, TBME, doi:10.1109/TBME.2017.2763460. February 2018 Featured issue

17.  S.P. Arunachalam, S. Kapa, S. Mulpuru, P. Friedman, and E.G. Tolkacheva. Novel Approaches for Quantitative Electrogram Analysis for Intraprocedural Guidance for Catheter Ablation: A Case of a Patient with Persistent Atrial Fibrillation, Journal of Nuclear Medicine and Biomedical Imaging, 2017, doi: 10.15761/NMBI.1000121

18.  E.G. Tolkacheva, X. Zhao, S. Zlochiver, Y. Mori. “Computational and mathematical methods in cardiovascular diseases”, Computational and Mathematical Methods in Medicine, vol. 2017, Article ID 4205735, 2017. doi:10.1155/2017/4205735.

19.  S. Zlochiver, Ch. Johnson and E.G. Tolkacheva. “Constant DI Pacing Suppresses Cardiac Alternans Formation in Numerical Cable Models”, Chaos, 2017, DOI: 10.1063/1.4999355

20.  S.W. Lee, Q. Li, I. Libbus, X. Xie, B. KenKnight, M. Garry, E.G. Tolkacheva. “Chronic cyclic vagus nerve stimulation has beneficial electrophysiological effects on healthy hearts in the absence of autonomic imbalance”, Physiol Rep. 2016 May;4(9). pii: e12786. doi: 10.14814/phy2.12786.

21.  N. Wei, Y. Mori, and E. G. Tolkacheva, The dual effect of ephaptic coupling on cardiac conduction with heterogeneous expression of connexin 43, J Theor Biol. 2016 May 21;397:103-14.