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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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
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Izumi-Nakaseko H, Sakamoto K, Goto A, Kambayashi R, Matsumoto A, Takei Y, Takahara A, Sugiyama A. Characterization of pathological remodeling in the chronic atrioventricular block cynomolgus monkey heart. Front Pharmacol 2023; 14:1055031. [PMID: 36744259 PMCID: PMC9892184 DOI: 10.3389/fphar.2023.1055031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 01/02/2023] [Indexed: 01/20/2023] Open
Abstract
We studied time course of pathological remodeling occurring in the cynomolgus monkey hearts against persistent atrioventricular block condition (n = 10). The atrioventricular block induced the ventricular and atrial dilation followed by the ventricular hypertrophy. Interstitial fibrosis in the ventricle was also observed along with gradual increases in the plasma angiotensin II and aldosterone concentrations. These adaptations were associated with the changes in gene expression profiling reflecting fibrosis and hypertrophy. Atrioventricular block reduced the ventricular rate and cardiac output, but the ejection fraction and stroke volume increased, whereas the cardiac output was gradually restored to its basal level. Systolic/diastolic blood pressure after the atrioventricular block was kept equal to or lower than that before the block, according with lack of increase in the plasma catecholamine levels. Chronic atrioventricular block gradually prolonged the QRS width and JT interval, leading to the QT interval prolongation in conscious state. 10 mg/kg of dl-sotalol hydrochloride induced torsade de pointes (TdP) in 6 out of 10 animals by 15 months. Animals showing longer QTcF under anesthesia after the atrioventricular block developed dl-sotalol-induced TdP earlier. No marked difference was observed in pharmacokinetics of dl-sotalol between 1 and 7 months after the atrioventricular block. Each TdP spontaneously terminated, reflecting a monkey's relatively small "effective size of the heart (=∛(left ventricular weight)/wavelength of reentry)". These fundamental knowledge will help better utilize the chronic atrioventricular block monkeys as an in vivo proarrhythmia model for detecting drug-induced TdP.
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Affiliation(s)
| | | | - Ai Goto
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Ryuichi Kambayashi
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Akio Matsumoto
- Department of Aging Pharmacology, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Yoshinori Takei
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo, Japan
| | - Akira Takahara
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Chiba, Japan
| | - Atsushi Sugiyama
- Department of Pharmacology, Faculty of Medicine, Toho University, Tokyo, Japan,Department of Aging Pharmacology, Faculty of Medicine, Toho University, Tokyo, Japan,*Correspondence: Atsushi Sugiyama,
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Varkevisser R, van der Heyden MAG, Tieland RG, Beekman JDM, Vos MA. Vernakalant is devoid of proarrhythmic effects in the complete AV block dog model. Eur J Pharmacol 2013; 720:49-54. [PMID: 24211677 DOI: 10.1016/j.ejphar.2013.10.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 10/25/2013] [Accepted: 10/29/2013] [Indexed: 11/28/2022]
Abstract
The anesthetized chronic AV-blocked dog (cAVB) and methoxamine-sensitized rabbit model are widely used to determine pro-arrhythmic properties of drugs. In general, both models show similar results. However, conflicting data have also been reported; K201 and AZD1305 induced Torsade de Pointes (TdP) exclusively in cAVB dogs. Vernakalant, an antiarrhythmic drug that blocks several ion channels has been approved only in Europe. Its propensity to induce repolarization-dependent TdP arrhythmias has been evaluated solely in the methoxamine-sensitized rabbits. We therefore assessed the proarrhythmic potential of vernakalant in the cAVB dog model. Vernakalant was evaluated in 10 mongrel dogs (sinus rhythm (SR) 2mg/kg; chronic AV block (cAVB) 2+3mg/kg). The same dogs were challenged with dofetilide (25 μg/kg) to evaluate TdP inducibility. During the serial experiments the animals were paced from the right ventricular apex (60 beats/min). Short-term variability of repolarization (STV) was quantified for proarrhythmic risk. In SR (n=8) vernakalant prolonged QT (265 ± 11 to 311 ± 18 ms P<0.01(**)) but not PQ or QRS. In cAVB (n=8), 2mg/kg vernakalant prolonged QT (391 ± 43 to 519 ± 73 ms(**)) and QRS (103 ± 24 to 108 ± 23 ms(**)). After a 30 min lag-time, 3mg/kg vernakalant (n=4) increased QT to a lesser extent (413 ± 34 to 454 ± 27 ms(**)) while maintaining QRS prolongation (114 ± 18 to 122 ± 20 ms(**)). Neither dose increased STV or caused arrhythmias. Dofetilide prolonged QT (398 ± 51 to 615 ± 71 ms(**)), increased STV (1.0 ± 0.4 to 2.2 ± 1.0 ms P<0.05(⁎)) and induced TdP arrhythmias in 6/8(⁎) cAVB dogs. Vernakalant did not induce arrhythmias in the cAVB dog model. Higher dosages (3mg/kg) did not prolong repolarization further whereas negative inotropic effects were starting to become apparent precluding further increases in dose.
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Affiliation(s)
- Rosanne Varkevisser
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM Utrecht, The Netherlands
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