1
|
Van Den Abeele R, Hendrickx S, Van Nieuwenhuyse E, Dunnink A, Panfilov AV, Vos MA, Wülfers EM, Vandersickel N. Directed graph mapping shows rotors maintain non-terminating and focal sources maintain self-terminating Torsade de Pointes in canine model. Front Physiol 2023; 14:1201260. [PMID: 37565147 PMCID: PMC10411729 DOI: 10.3389/fphys.2023.1201260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/28/2023] [Indexed: 08/12/2023] Open
Abstract
Torsade de Pointes is a polymorphic ventricular tachycardia which is as yet incompletely understood. While the onset of a TdP episode is generally accepted to be caused by triggered activity, the mechanisms for the perpetuation is still under debate. In this study, we analysed data from 54 TdP episodes divided over 5 dogs (4 female, 1 male) with chronic atrioventricular block. Previous research on this dataset showed both reentry and triggered activity to perpetuate the arrhythmia. 13 of those TdP episodes showed reentry as part of the driving mechanism of perpetuating the episode. The remaining 41 episodes were purely ectopic. Reentry was the main mechanism in long-lasting episodes (>14 beats), while focal sources were responsible for maintaining shorter episodes. Building on these results, we re-analysed the data using directed graph mapping This program uses principles from network theory and a combination of positional data and local activation times to identify reentry loops and focal sources within the data. The results of this study are twofold. First, concerning reentry loops, we found that on average non-terminating (NT) episodes (≥10 s) show significantly more simultaneous reentry loops than self-terminating (ST) TdP (<10 s). Non-terminating episodes have on average 2.72 ± 1.48 simultaneous loops, compared to an average of 1.33 ± 0.66 for self-terminating episodes. In addition, each NT episode showed a presence of (bi-)ventricular loops between 10.10% and 69.62% of their total reentry duration. Compared to the ST episodes, only 1 in 4 episodes (25%) showed (bi-)ventricular reentry, lasting only 7.12% of its total reentry duration. This suggests that while focal beats trigger TdP, macro-reentry and multiple simultaneous localized reentries are the major drivers of long-lasting episodes. Second, using heatmaps, we found focal sources to occur in preferred locations, instead of being distributed randomly. This may have implications on treatment if such focal origins can be disabled reliably.
Collapse
Affiliation(s)
- Robin Van Den Abeele
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Sander Hendrickx
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Enid Van Nieuwenhuyse
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Albert Dunnink
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Alexander V. Panfilov
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
- Laboratory of Computational Biology and Medicine, Ural Federal University, Yekaterinburg, Russia
- World-Class Research Center “Digital Biodesign and Personalized Healthcare”, Sechenov University, Moscow, Russia
| | - Marc A. Vos
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Eike M. Wülfers
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Nele Vandersickel
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Ghent, Belgium
| |
Collapse
|
2
|
Himel HD, Cupelli M, Boutjdir M, El-Sherif N. Voltage/Calcium Uncoupling Underlies Sustained Torsade de Pointes Ventricular Tachyarrhythmia in an Experimental Model of Long QT Syndrome. Front Physiol 2021; 12:617847. [PMID: 33584347 PMCID: PMC7876465 DOI: 10.3389/fphys.2021.617847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/12/2021] [Indexed: 11/23/2022] Open
Abstract
Background Clinical experience showed that the majority of Torsade de Pointes (TdP) ventricular tachyarrhythmia (VT) in patients with long QT syndrome (LQTS) are self-terminating (ST), but the few that are non-self-terminating (NST) are potentially fatal. A paramount issue in clinical arrhythmology is to understand the electrophysiological mechanism of ST vs. NST TdP VT. Methods We investigated the electrophysiological mechanism of ST vs. NST TdP VT in the guinea pig Anthopleurin-A experimental model of LQTS, a close surrogate model of congenital LQT3. We utilized simultaneous optical recordings of membrane voltage (Vm) and intracellular calcium (Cai) and a robust analytical method based on spatiotemporal entropy difference (Ed) to investigate the hypothesis that early Vm/Cai uncoupling during TdP VT can play a primary role in perpetuation of VT episodes. Results We analyzed a total of 35 episodes of TdP VT from 14 guinea pig surrogate models of LQTS, including 23 ST and 12 NST VTs. Ed values for NST VT were significantly higher than Ed values for ST VT. Analysis of wave front topology during the early phase of ST VT showed the Cai wave front following closely Vm wave front consistent with a lower degree of Ed. In contrast, NST VT was associated with uncoupling of Vm/Cai wave fronts during the first 2 or 3 cycles of VT associated with early wave break propagation pattern. Conclusions Utilizing a robust analytical method we showed that, in comparison to ST TdP VT, NST VT was consistently predated by early uncoupling of Vm/Cai that destabilized wave front propagation and can explain a sustained complex reentrant excitation pattern.
Collapse
Affiliation(s)
- Herman D Himel
- Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY, United States
| | - Michael Cupelli
- Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY, United States.,Downstate Medical Center, State University of New York, Brooklyn, NY, United States
| | - Mohamed Boutjdir
- Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY, United States.,Downstate Medical Center, State University of New York, Brooklyn, NY, United States.,School of Medicine, New York University, New York, NY, United States
| | - Nabil El-Sherif
- Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY, United States.,Downstate Medical Center, State University of New York, Brooklyn, NY, United States
| |
Collapse
|
3
|
El-Sherif N, Turitto G, Boutjdir M. Acquired Long QT Syndrome and Electrophysiology of Torsade de Pointes. Arrhythm Electrophysiol Rev 2019; 8:122-130. [PMID: 31114687 PMCID: PMC6528034 DOI: 10.15420/aer.2019.8.3] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/04/2019] [Indexed: 12/16/2022] Open
Abstract
Congenital long QT syndrome (LQTS) has been the most investigated cardiac ion channelopathy. Although congenital LQTS remains the domain of cardiologists, cardiac electrophysiologists and specialised centres, the much more frequently acquired LQTS is the domain of physicians and other members of healthcare teams required to make therapeutic decisions. This paper reviews the electrophysiological mechanisms of acquired LQTS, its ECG characteristics, clinical presentation, and management. The paper concludes with a comprehensive review of the electrophysiological mechanisms of torsade de pointes.
Collapse
Affiliation(s)
- Nabil El-Sherif
- SUNY Downstate Medical CenterNY, US
- VA NY Harbor Healthcare SystemNY, US
| | - Gioia Turitto
- Weill Cornell Medical College, NewYork-Presbyterian Brooklyn Methodist HospitalNY, US
| | - Mohamed Boutjdir
- SUNY Downstate Medical CenterNY, US
- VA NY Harbor Healthcare SystemNY, US
- NYU School of MedicineNew York NY, US
| |
Collapse
|