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Sliwinski P. Geometric working volume of a satellite positive displacement machine. Sci Rep 2024; 14:11195. [PMID: 38755260 PMCID: PMC11099030 DOI: 10.1038/s41598-024-61773-1] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 05/09/2024] [Indexed: 05/18/2024] Open
Abstract
This article describes a method for determining the geometric working volume of satellite positive displacement machines (pump and motor). The working mechanism of these machines is satellite mechanism consisting of two non-circular gears (rotor and curvature) and circular gears (satellites). Two variants of the satellite mechanism are presented. In the first mechanism, the rolling line of the rotor is a sinusoid "wrapped" around a circle. In the second mechanism, the rolling line of the rotor is a double sinusoid "wrapped" around a circle. A method for calculating the area of the working chamber as a function of the rotor rotation angle is presented, based on mathematical formulae of the rotor, the curvature and the satellite rolling lines. It has been shown that the second variant of the satellite mechanism is advantageously characterised by a larger difference between the maximum area of the working chamber and the minimum area of this chamber. New mathematical formulas have been proposed to calculate the area of the working chamber for any angle of rotation of the shaft (rotor) based on the maximum and minimum values of the area of this chamber. It was thus confirmed that the geometric working volume depends on the maximum and minimum area of a working chamber and on the height of the satellite mechanism. The analyses of the area of the working chamber were carried out both for the mechanism without gears (the area delimited by the rolling lines of the elements of the mechanism) and for the real mechanism with gears. Differences in the values of these fields were also detected.
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Affiliation(s)
- Pawel Sliwinski
- Faculty of Mechanical Engineering and Ship Technology, Gdansk University of Technology, Gabriela Narutowicza 11/12 Str, 80-233, Gdansk, Poland.
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2
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Sliwinski P. Influence of operating pressure on the durability of a satellite hydraulic motor supplied by rapeseed oil. Sci Rep 2024; 14:10441. [PMID: 38714705 PMCID: PMC11076486 DOI: 10.1038/s41598-024-61072-9] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 04/30/2024] [Indexed: 05/10/2024] Open
Abstract
This article describes the results of a durability test of a hydraulic satellite motor supplied by rapeseed oil. The tests were carried out on a test stand in a power recuperation system. The tests of the motor were carried out at a constant shaft speed for three fixed pressure drops in the motor. This made it possible to demonstrate the influence of the motor operating pressure on the durability of the satellite mechanism. The influence of the pressure drop in the motor and the influence of the operating time on the motor absorbency, on the torque on the motor shaft and the influence on the volumetric and hydraulic-mechanical efficiency are also shown. The basic relationship between the efficiency of the motor and the temperature rise in the motor is also described. The results of the calculations of the temperature rise in the motor are compared with the experimental results. The article also shows which components of the motor's working mechanism wear out the fastest. The cause of the wear and failure is also explained.
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Affiliation(s)
- Pawel Sliwinski
- Faculty of Mechanical Engineering and Ship Technology (Division of Hydraulics and Pneumatics), Gdansk University of Technology, ul. Gabriela Narutowicza 11/12, 80-233, Gdańsk, Poland.
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Bryce DL. Double-rotation (DOR) NMR spectroscopy: Progress and perspectives. Solid State Nucl Magn Reson 2024; 130:101923. [PMID: 38471386 DOI: 10.1016/j.ssnmr.2024.101923] [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] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 03/14/2024]
Abstract
Double-rotation (DOR) solid-state NMR spectroscopy is a high-resolution technique developed in the late 1980s. Although multiple-quantum magic-angle spinning (MQMAS) became the most widely used high-resolution method for half-integer spin quadrupoles after 1995, development and application of DOR NMR to a variety of chemical and materials science problems has endured. This Trend article recapitulates the development of DOR NMR, discusses various applications, and describes possible future directions. The main technical limitations specific to DOR NMR are simply related to the size of the double rotor system. The relatively large outer rotor (and thus coil) used for most applications over the past 35 years translates into relatively low rotor spinning frequencies, a low filling factor, and weak radiofrequency powers available for excitation and for proton decoupling. Ongoing developments in NMR instrumentation, including ever-shrinking MAS rotors and spherical NMR rotors, could solve many of these problems and may augur a renaissance for DOR NMR.
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Affiliation(s)
- David L Bryce
- Department of Chemistry and Biomolecular Sciences, Centre for Catalysis Research and Innovation, and Nexus for Quantum Technologies, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario, K1N 6N5, Canada.
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Riku S, Inden Y, Yanagisawa S, Fujii A, Tomomatsu T, Nakagomi T, Shimojo M, Okajima T, Furui K, Suga K, Suzuki S, Shibata R, Murohara T. Distributions and number of drivers on real-time phase mapping associated with successful atrial fibrillation termination during catheter ablation for non-paroxysmal atrial fibrillation. J Interv Card Electrophysiol 2024; 67:303-317. [PMID: 37354370 DOI: 10.1007/s10840-023-01588-8] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 05/31/2023] [Indexed: 06/26/2023]
Abstract
BACKGROUND Real-time phase mapping (ExTRa™) is useful in determining the strategy of catheter ablation for non-paroxysmal atrial fibrillation (AF). This study aimed to investigate the features of drivers of AF associated with its termination during ablation. METHODS Thirty-six patients who underwent catheter ablation for non-paroxysmal AF using online real-time phase mapping (ExTRa™) were enrolled. A significant AF driver was defined as an area with a non-passively activated ratio of ≥ 50% on mapping analysis in the left atrium (LA). All drivers were simultaneously evaluated using a low-voltage area, complex fractionated atrial electrogram (CFAE), and rotational activity by unipolar electrogram analysis. The electrical characteristics of drivers were compared between patients with and without AF termination during the procedure. RESULTS Twelve patients achieved AF termination during the procedure. The total number of drivers detected on the mapping was significantly lower (4.4 ± 1.6 vs. 7.4 ± 3.8, p = 0.007), and the drivers were more concentrated in limited LA regions (2.8 ± 0.9 vs. 3.9 ± 1.4, p = 0.009) in the termination group than in the non-termination group. The presence of drivers 2-6 with limited (≤ 3) LA regions showed a tenfold increase in the likelihood of AF termination, with 83% specificity and 67% sensitivity. Among 231 AF drivers, the drivers related to termination exhibited a greater overlap of CFAE (56.8 ± 34.1% vs. 39.5 ± 30.4%, p = 0.004) than the non-related drivers. The termination group showed a trend toward a lower recurrence rate after ablation (p = 0.163). CONCLUSIONS Rotors responsible for AF maintenance may be characterized in cases with concentrated regions and fewer drivers on mapping.
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Affiliation(s)
- Shuro Riku
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Yasuya Inden
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Satoshi Yanagisawa
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
| | - Aya Fujii
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Toshiro Tomomatsu
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Toshifumi Nakagomi
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Masafumi Shimojo
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Takashi Okajima
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Koichi Furui
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Kazumasa Suga
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Susumu Suzuki
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Rei Shibata
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Toyoaki Murohara
- Department of Cardiology, Nagoya University Graduate School of Medicine, 65 Tsurumaicho, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
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Majumder R, Jana D, Ghorai BK. Synthesis of V-shaped Thiophene Based Rotor-Stilbene: Substituent Dependent Aggregation and Photophysical Properties. J Fluoresc 2024:10.1007/s10895-024-03591-2. [PMID: 38319521 DOI: 10.1007/s10895-024-03591-2] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 01/15/2024] [Indexed: 02/07/2024]
Abstract
Thiophene core V-shaped rotor-stilbene derivatives have been synthesized utilizing two-fold Heck coupling reaction. These compounds are blue emitters with moderate quantum yield in dilute solution. Rotor nature of the synthesized stilbenes supports aggregation induced emission (AIE) behaviour and they show substituent dependent emission behavior in aggregate state. In presence of donating groups (e.g., tert-butyl, methoxy, diphenylamine group) in stilbenes, they exhibit AIE property. But with the introduction of electron withdrawing group (nitro group), they shows aggregation caused quenching (ACQ) behavior. Different types of nano-aggregates formation is observed in aggregated state, which was confirmed by dynamic light scattering (DLS) and scanning electron microscopy (SEM) studies. The details photophysical (absorption, fluorescence, and lifetime), electrochemical property (cyclic voltammetry) and thermal stability have been investigated. Optimized structure, energy and electronic distribution of molecular orbitals have been studied by theoretical calculation.
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Affiliation(s)
- Riya Majumder
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711103, India
| | - Debabrata Jana
- Department of Chemistry, Ramakrishna Mission Vivekananda Centenary College, Kolkata, 700 118, India
| | - Binay Krishna Ghorai
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711103, India.
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Levitt DG, Levitt MD. Development of a Pharmacokinetic Model That Accounts for the Plasma Concentrations of Conjugated and Unconjugated Bilirubin Observed in a Variety of Disease States. Clin Exp Gastroenterol 2023; 16:277-289. [PMID: 38143515 PMCID: PMC10749172 DOI: 10.2147/ceg.s438140] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/13/2023] [Indexed: 12/26/2023] Open
Abstract
Introduction For a large variety of liver pathologies, the plasma unconjugated (UB) and conjugated (CB) bilirubin concentrations appear to be coupled. For example, in alcoholic cirrhosis, UB and CB are roughly the same over a large range of total bilirubin, requiring an initial massive increase (about 40-fold) in plasma CB to reach the level of UB and then similar increases in UB and CB as the disease progresses. This coupling has been either unrecognized or ignored and this paper is the first attempt to try to explain it quantitatively in terms of known hepatic cell metabolic and membrane transport properties. Methods A simplified pharmacokinetic model is developed and applied to a variety of hyperbilirubinemic pathologies. A central feature of the model is based on the recent observation that double knockout of the rat OATP1A and OATP1B hepatic transporters produces a roughly 400-fold increase in plasma CB, indicating that there is a normal rapid recycling of CB from the cell to the plasma with reuptake via OATP. We use the experimental rat Km of OATP CB transport to show that OATP uptake becomes saturated at relatively low plasma CB concentrations, decreasing uptake, and producing massive (up to 1000-fold) increases in CB in some pathologies. It is assumed that UB and CB are competing for the OATP transporter, producing the increased plasma UB that is observed in "pure" CB pathologies. Results The model accurately describes the clinically observed UB and CB for pure UB (Gilbert's, hemolytic anemia) and CB (Dubin-Johnson, Rotor syndrome, biliary atresia) pathologies as well as in cirrhosis. Conclusion This model is a preliminary, first attempt to quantitatively describe UB and CB pharmacokinetics. It is hoped that it will stimulate more detailed measurements and analysis.
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Affiliation(s)
- David G Levitt
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Michael D Levitt
- Research Service, Veterans Affairs Medical Center, Minneapolis, MN, USA
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Terashima H, Homma M, Kojima S. Site-Directed Cross-Linking Between Bacterial Flagellar Motor Proteins In Vivo. Methods Mol Biol 2023; 2646:71-82. [PMID: 36842107 DOI: 10.1007/978-1-0716-3060-0_7] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
The bacterial flagellum employs a rotary motor embedded on the cell surface. The motor consists of the stator and rotor elements and is driven by ion influx (typically H+ or Na+) through an ion channel of the stator. Ion influx induces conformational changes in the stator, followed by changes in the interactions between the stator and rotor. The driving force to rotate the flagellum is thought to be generated by changing the stator-rotor interactions. In this chapter, we describe two methods for investigating the interactions between the stator and rotor: site-directed in vivo photo-crosslinking and site-directed in vivo cysteine disulfide crosslinking.
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Affiliation(s)
- Hiroyuki Terashima
- Department of Bacteriology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
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Spitzer SG, Miller JM, Sommer P, Szili-Torok T, Reddy VY, Nölker G, Williams C, Sarver A, Wilber DJ. Randomized evaluation of redo ablation procedures of atrial fibrillation with focal impulse and rotor modulation-guided procedures: the REDO-FIRM study. Europace 2023; 25:74-82. [PMID: 36056882 PMCID: PMC10103554 DOI: 10.1093/europace/euac122] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [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: 11/15/2021] [Accepted: 05/25/2022] [Indexed: 11/12/2022] Open
Abstract
AIMS REDO-FIRM evaluated safety and effectiveness of conventional vs. focal impulse and rotor modulation (FIRM)-guided ablation of recurrent persistent or paroxysmal atrial fibrillation (AF) after an initial AF ablation procedure. METHODS AND RESULTS This prospective, multicentre, randomized study included patients with a single prior AF ablation, but with recurrent AF and reconnected pulmonary veins (PVs). Conventional ablation generally included PV re-isolation; however, additional ablation was permitted per physician discretion. In the FIRM arm, beyond PV re-isolation, basket catheter-based FIRM mapping created dynamic animations of putative rotors, which were targeted for ablation. Between May 2016 and July 2019, 269 subjects were randomized, with 243 subjects completing 12-month follow-up. Ablation beyond re-pulmonary vein isolation, the FIRM vs. Conventional arms did not differ significantly: cavo-tricuspid isthmus -9.0% vs. 15.3%, caval vein isolation -1.5% vs. 0.8%, non-PV trigger -2.2% vs. 3.8%, other -11.9% vs. 13.0%. Single procedure 12-month freedom from AF/atrial tachycardia/atrial flutter-recurrence was 63.3% (76/120) vs. 59.0% (72/122) in the FIRM and Conventional arms (P = 0.3503). Efficacy was similar in the paroxysmal and persistent AF subgroups (P = 0.22 and P = 0.48). The 10-day and 12-month safety endpoints were achieved in 93.3% vs. 93.8% (P = 0.89) and 88.4% vs. 93.4% (P = 0.22) in the FIRM and Conventional arms, respectively. CONCLUSIONS In REDO-FIRM, as compared to standard ablation, FIRM-guided ablation did not provide additional efficacy in redo ablation procedures, but FIRM-guided ablation was equally safe. Additional studies are necessary to identify any potential population able to benefit from FIRM-guided ablation.
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Affiliation(s)
- Stefan G Spitzer
- Praxisklinik Herz und Gefäße, 01099 Dresden, and Brandenburg University of Technology Cottbus-Senftenberg, Institute of Medical Technology, 03046 Cottbus, Germany
| | - John M Miller
- Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Philipp Sommer
- Herz-und Diabeteszentrum NRW, Universitätsklinik der Ruhr-Universität Bochum, Bad Oeynhausen 32545, Germany
| | | | - Vivek Y Reddy
- Helmsley Electrophysiology Center - Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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Abstract
Treatment of atrial fibrillation (AF) remains challenging despite significant progress in understanding its underlying mechanisms. The first detailed, quantitative theory of functional re-entry, the 'leading circle' model, was developed more than 40 years ago. Subsequently, in decades of study, an alternative paradigm based on spiral waves has long been postulated to drive AF. The rotor as a 'spiral wave generator' is a curved 'vortex' formed by spin motion in the two-dimensional plane, identified using advanced mapping methods in experimental and clinical AF. However, it is challenging to achieve complementary results between experimental results and clinical studies due to the limitation in research methods and the complexity of the rotor mechanism. Here, we review knowledge garnered over decades on generation, electrophysiological properties, and three-dimensional (3D) structure diversity of the rotor mechanism and make a comparison among recent clinical approaches to identify rotors. Although initial studies of rotor ablation at many independent centres have achieved promising results, some inconclusive outcomes exist in others. We propose that the clinical rotor identification might be substantially influenced by (i) non-identical surface activation patterns, which resulted from a diverse 3D form of scroll wave, and (ii) inadequate resolution of mapping techniques. With rapidly advancing theoretical and technological developments, future work is required to resolve clinically relevant limitations in current basic and clinical research methodology, translate from one to the other, and resolve available mapping techniques.
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Affiliation(s)
- Chang-Hao Xu
- Department of Cardiology, Shanghai Chest Hospital, School of Medicine,
Shanghai Jiao Tong University, 241 Huaihai West Road, Xuhui
District, Shanghai 200030, China
| | - Feng Xiong
- Montreal Heart Institute, Department of Medicine, University of
Montreal, 5000, Bélanger street, Montréal, Québec H1T
1C8, Canada
| | - Wei-Feng Jiang
- Department of Cardiology, Shanghai Chest Hospital, School of Medicine,
Shanghai Jiao Tong University, 241 Huaihai West Road, Xuhui
District, Shanghai 200030, China
| | - Xu Liu
- Department of Cardiology, Shanghai Chest Hospital, School of Medicine,
Shanghai Jiao Tong University, 241 Huaihai West Road, Xuhui
District, Shanghai 200030, China
| | - Tao Liu
- Corresponding authors. Tao Liu, 238 Jiefang Road, Wuchang
District, Wuhan, Hubei 430060, China. Tel: +86 (027) 8804 1911, Fax:+86-(027)-8804-2292.
E-mail address:; Mu Qin, 241 Huaihai
West Road, Xuhui District, Shanghai, 200030, China. Tel: +8621628219902603, Fax:
+862162821105. E-mail address:
| | - Mu Qin
- Corresponding authors. Tao Liu, 238 Jiefang Road, Wuchang
District, Wuhan, Hubei 430060, China. Tel: +86 (027) 8804 1911, Fax:+86-(027)-8804-2292.
E-mail address:; Mu Qin, 241 Huaihai
West Road, Xuhui District, Shanghai, 200030, China. Tel: +8621628219902603, Fax:
+862162821105. E-mail address:
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Dharmaprani D, Jenkins EV, Quah JX, Lahiri A, Tiver K, Mitchell L, Bradley CP, Hayward M, Paterson DJ, Taggart P, Clayton RH, Nash MP, Ganesan AN. A governing equation for rotor and wavelet number in human clinical ventricular fibrillation: Implications for sudden cardiac death. Heart Rhythm 2021:S1547-5271(21)02235-9. [PMID: 34662707 DOI: 10.1016/j.hrthm.2021.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 09/29/2021] [Accepted: 10/08/2021] [Indexed: 11/21/2022]
Abstract
BACKGROUND Ventricular fibrillation (VF) is characterized by multiple wavelets and rotors. No equation to predict the number of rotors and wavelets observed during fibrillation has been validated in human VF. OBJECTIVE The purpose of this study was to test the hypothesis that a single equation derived from a Markov M/M/∞ birth-death process could predict the number of rotors and wavelets occurring in human clinical VF. METHODS Epicardial induced VF (256-electrode) recordings obtained from patients undergoing cardiac surgery were studied (12 patients; 62 epochs). Rate constants for phase singularity (PS) (which occur at the pivot points of rotors) and wavefront (WF) formation and destruction were derived by fitting distributions to PS and WF interformation and lifetimes. These rate constants were combined in an M/M/∞ governing equation to predict the number of PS and WF in VF episodes. Observed distributions were compared to those predicted by the M/M/∞ equation. RESULTS The M/M/∞ equation accurately predicted average PS and WF number and population distribution, demonstrated in all epochs. Self-terminating episodes of VF were distinguished from VF episodes requiring termination by a trend toward slower PS destruction, slower rates of PS formation, and a slower mixing rate of the VF process, indicated by larger values of the second largest eigenvalue modulus of the M/M/∞ birth-death matrix. The longest-lasting PS (associated with rotors) had shorter interactivation time intervals compared to shorter-lasting PS lasting <150 ms (∼1 PS rotation in human VF). CONCLUSION The M/M/∞ equation explains the number of wavelets and rotors observed, supporting a paradigm of VF based on statistical fibrillatory dynamics.
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Tilz RR, Lenz C, Sommer P, Roza MS, Sarver AE, Williams CG, Heeger C, Hindricks G, Vogler J, Eitel C. Focal Impulse and Rotor Modulation Ablation vs. Pulmonary Vein isolation for the treatment of paroxysmal Atrial Fibrillation: results from the FIRMAP AF study. Europace 2021; 23:722-730. [PMID: 33351076 PMCID: PMC8139814 DOI: 10.1093/europace/euaa378] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 12/09/2020] [Indexed: 12/19/2022] Open
Abstract
AIMS Pulmonary vein isolation (PVI) is the gold standard for atrial fibrillation (AF) ablation. Recently, catheter ablation targeting rotors or focal sources has been developed for treatment of AF. This study sought to compare the safety and effectiveness of Focal Impulse and Rotor Modulation (FIRM)-guided ablation as the sole ablative strategy with PVI in patients with paroxysmal AF. METHODS AND RESULTS We conducted a multicentre, randomized trial to determine whether FIRM-guided radiofrequency ablation without PVI (FIRM group) was non-inferior to PVI (PVI group) for treatment of paroxysmal AF. The two primary efficacy end points were (i) acute success defined as elimination of AF rotors (FIRM group) or isolation of all pulmonary veins (PVI group) and (ii) long-term success defined as single-procedure freedom from AF/atrial tachycardia (AT) recurrence 12 months after ablation. The study was closed early by the sponsor. At the time of study closure, any pending follow-up visits were waived. A total of 51 patients (mean age 63 ± 10.6 years, 57% male) were enrolled. All PVs were successfully isolated in the PVI group and all rotors were successfully eliminated in the FIRM group. Single-procedure effectiveness was 31.3% (5/16) in the FIRM group and 80% (8/10) in the PVI group at 12 months. Three vascular access complications occurred in the FIRM group. CONCLUSION These partial study effectiveness results reinforce the importance of PVI in paroxysmal AF patients and indicate that FIRM-guided ablation alone (without PVI) is not an effective strategy for treatment of paroxysmal AF in most patients.
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Affiliation(s)
- Roland R Tilz
- University Heart Center Lübeck, Medical Clinic II, Department of Electrophysiology, Lübeck, Germany
| | - Corinna Lenz
- Unfallkrankenhaus Berlin, Klinik für Innere Medizin/Kardiologie, Berlin, Germany
| | - Philipp Sommer
- Heart Center Leipzig, Department of Electrophysiology, Leipzig, Germany
| | - Meyer-Saraei Roza
- University Heart Center Lübeck, Medical Clinic II, Department of Electrophysiology, Lübeck, Germany
| | | | | | - Christian Heeger
- University Heart Center Lübeck, Medical Clinic II, Department of Electrophysiology, Lübeck, Germany
| | - Gerhard Hindricks
- Heart Center Leipzig, Department of Electrophysiology, Leipzig, Germany
| | - Julia Vogler
- University Heart Center Lübeck, Medical Clinic II, Department of Electrophysiology, Lübeck, Germany
| | - Charlotte Eitel
- University Heart Center Lübeck, Medical Clinic II, Department of Electrophysiology, Lübeck, Germany
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12
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Abstract
Mechanisms sustaining atrial fibrillation are yet to be clarified. This article focuses on milestones in the theory of atrial fibrillation and addresses the different leading hypotheses concerning atrial fibrillation mechanisms. We start off with electric potential originating from the pulmonary vein, which triggers atrial fibrillation, discuss classic activation mapping and phase mapping as well as computer models, which have contributed to the our understanding of atrial fibrillation, and end with new mapping methods and studies highlighting the advantages and disadvantages of current mechanistic hypotheses. The technical evolution of mapping atrial fibrillation has led to new insights into the potential mechanisms underlying atrial fibrillation. A comparison between methods is essential for understanding the advantages and disadvantages of each method when mapping atrial fibrillation. Ultimately, the combination of several methods might shed light on the underlying mechanisms of atrial fibrillation and lead to a better understanding of atrial fibrillation and subsequently improve treatment of this condition.
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Abstract
One of the central systems responsible for bacterial motility is the flagellum. The bacterial flagellum is a macromolecular protein complex that is more than five times the cell length. Flagella-driven motility is coordinated via a chemosensory signal transduction pathway, and so bacterial cells sense changes in the environment and migrate towards more desirable locations. The flagellum of Salmonella enterica serovar Typhimurium is composed of a bi-directional rotary motor, a universal joint and a helical propeller. The flagellar motor, which structurally resembles an artificial motor, is embedded within the cell envelop and spins at several hundred revolutions per second. In contrast to an artificial motor, the energy utilized for high-speed flagellar motor rotation is the inward-directed proton flow through a transmembrane proton channel of the stator unit of the flagellar motor. The flagellar motor realizes efficient chemotaxis while performing high-speed movement by an ingenious directional switching mechanism of the motor rotation. To build the universal joint and helical propeller structures outside the cell body, the flagellar motor contains its own protein transporter called a type III protein export apparatus. In this chapter we summarize the structure and assembly of the Salmonella flagellar motor complex.
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Affiliation(s)
- Yusuke V Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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14
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Spitzer SG, Károlyi L, Rämmler C, Zieschank M, Langbein A. Retrospective analysis of FIRM-guided ablation in patients with recurrent atrial fibrillation: a single-center study. Herzschrittmacherther Elektrophysiol 2020; 31:417-425. [PMID: 33052485 DOI: 10.1007/s00399-020-00724-5] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 11/25/2022]
Abstract
BACKGROUND Ablation of recurrent atrial fibrillation (AF) is common. Studies indicate that AF recurrence is primarily due to pulmonary vein (PV) re-conduction. This retrospective analysis characterized and evaluated recurrent AF patients using focal impulse and rotor mapping (FIRM) plus PV re-isolation, with follow up at 3, 6, 12, and 24 months after the repeat ablation. METHODS AND RESULTS Patients (consecutive, n = 100) underwent FIRM-guided ablation followed by conventional PV re-isolation for recurrent AF treatment. All FIRM patients had failed one or more conventional ablation procedures (1.4 ± 0.08) for paroxysmal (14%), persistent (15%), and long-standing persistent (71%) AF. Stable rotors were identified in 97/100 patients: 60% in the right atrium (RA) and 82% in left atrium (LA) (mean 1.5 ± 0.8 and 2.1 ± 1.2 per patient, respectively). No correlation was noted between the previous number of ablations, AF duration, or LA diameter to the number of rotors (R2 = 0.0039, R2 = 0.0017, and R2 = 0.006, respectively). In this limited observation, only 22% of identified rotors were associated with proximity to low voltage areas. The 12- and 24-month arrhythmia free rate was 93% (13/14) and 92% (12/13) for paroxysmal AF, 60% (9/15) and 47% (7/15) for persistent AF, and 70% (48/69) and 64% (43/67) for long-standing persistent AF, respectively, after a single FIRM procedure and re-isolation of the veins. CONCLUSIONS The data show a benefit for FIRM-guided ablation in recurrent AF at 12 months. No correlation was found between rotors and tissue characterization, AF duration, or previous number of ablations, suggesting that rotors may play an independent role in maintaining recurrent AF after prior failed ablation.
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Affiliation(s)
- Stefan Georg Spitzer
- Praxisklinik Herz und Gefäße Dresden, Kardiologie-Angiologie-Radiologie, Nuklearmedizin, Akademische Lehrpraxisklinik der TU Dresden, Forststr. 3, 01099, Dresden, Germany.
- Institut für Medizintechnologie, Campus Senftenberg, Brandenburgische Technische Universität Cottbus-Senftenberg, Universitätsplatz 1, 01968, Senftenberg, Germany.
| | - László Károlyi
- Praxisklinik Herz und Gefäße Dresden, Kardiologie-Angiologie-Radiologie, Nuklearmedizin, Akademische Lehrpraxisklinik der TU Dresden, Forststr. 3, 01099, Dresden, Germany
| | - Carola Rämmler
- Praxisklinik Herz und Gefäße Dresden, Kardiologie-Angiologie-Radiologie, Nuklearmedizin, Akademische Lehrpraxisklinik der TU Dresden, Forststr. 3, 01099, Dresden, Germany
| | - Mirko Zieschank
- Praxisklinik Herz und Gefäße Dresden, Kardiologie-Angiologie-Radiologie, Nuklearmedizin, Akademische Lehrpraxisklinik der TU Dresden, Forststr. 3, 01099, Dresden, Germany
| | - Anke Langbein
- Praxisklinik Herz und Gefäße Dresden, Kardiologie-Angiologie-Radiologie, Nuklearmedizin, Akademische Lehrpraxisklinik der TU Dresden, Forststr. 3, 01099, Dresden, Germany
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15
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Gisbert V, Jiménez-Serrano S, Roses-Albert E, Rodrigo M. Atrial location optimization by electrical measures for Electrocardiographic Imaging. Comput Biol Med 2020; 127:104031. [PMID: 33096296 DOI: 10.1016/j.compbiomed.2020.104031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 07/02/2020] [Revised: 09/07/2020] [Accepted: 10/01/2020] [Indexed: 12/18/2022]
Abstract
BACKGROUND The Electrocardiographic Imaging (ECGI) technique, used to non-invasively reconstruct the epicardial electrical activity, requires an accurate model of the atria and torso anatomy. Here we evaluate a new automatic methodology able to locate the atrial anatomy within the torso based on an intrinsic electrical parameter of the ECGI solution. METHODS In 28 realistic simulations of the atrial electrical activity, we randomly displaced the atrial anatomy for ±2.5 cm and ±30° on each axis. An automatic optimization method based on the L-curve curvature was used to estimate the original position using exclusively non-invasive data. RESULTS The automatic optimization algorithm located the atrial anatomy with a deviation of 0.5 ± 0.5 cm in position and 16.0 ± 10.7° in orientation. With these approximate locations, the obtained electrophysiological maps reduced the average error in atrial rate measures from 1.1 ± 1.1 Hz to 0.5 ± 1.0 Hz and in the phase singularity position from 7.2 ± 4.0 cm to 1.6 ± 1.7 cm (p < 0.01). CONCLUSIONS This proposed automatic optimization may help to solve spatial inaccuracies provoked by cardiac motion or respiration, as well as to use ECGI on torso and atrial anatomies from different medical image systems.
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Affiliation(s)
- Víctor Gisbert
- ITACA Institute, Universitat Politècnica de València, Valencia, Spain
| | - Santiago Jiménez-Serrano
- ITACA Institute, Universitat Politècnica de València, Valencia, Spain; Proteu Tecnologia Aplicada Coop V, Spain
| | - Eduardo Roses-Albert
- ITACA Institute, Universitat Politècnica de València, Valencia, Spain; Proteu Tecnologia Aplicada Coop V, Spain
| | - Miguel Rodrigo
- ITACA Institute, Universitat Politècnica de València, Valencia, Spain.
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16
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Abstract
Drivers are increasingly studied ablation targets for atrial fibrillation (AF). However, results from ablation remain controversial. First, outcomes vary between centers and patients. Second, it is unclear how best to perform driver ablation. Third, there is a lack of practical guidance on how to identify critical from secondary sites using different AF mapping methods. This article addresses each of these issues.
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Affiliation(s)
- Junaid Zaman
- Stanford University, 780 Welch Road, Suite CJ250F, Stanford, CA 94305, USA; Imperial College London, London, UK
| | - Tina Baykaner
- Department of Medicine/Cardiovascular Medicine, Stanford University, 780 Welch Road, Suite CJ250F, Stanford, CA 94305, USA
| | - Sanjiv M Narayan
- Department of Medicine/Cardiovascular Medicine and Cardiovascular Institute, Stanford University, 780 Welch Road, Suite CJ250F, MC 5773, Stanford, CA 94305, USA.
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17
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Costoya-Sánchez A, Climent AM, Hernández-Romero I, Liberos A, Fernández-Avilés F, Narayan SM, Atienza F, Guillem MS, Rodrigo M. Automatic quality electrogram assessment improves phase-based reentrant activity identification in atrial fibrillation. Comput Biol Med 2020; 117:103593. [PMID: 32072974 PMCID: PMC10984645 DOI: 10.1016/j.compbiomed.2019.103593] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 11/30/2022]
Abstract
Identification of reentrant activity driving atrial fibrillation (AF) is increasingly important to ablative therapies. The goal of this work is to study how the automatically-classified quality of the electrograms (EGMs) affects reentrant AF driver localization. EGMs from 259 AF episodes obtained from 29 AF patients were recorded using 64-poles basket catheters and were manually classified according to their quality. An algorithm capable of identifying signal quality was developed using time and spectral domain parameters. Electrical reentries were identified in 3D phase maps using phase transform and were compared with those obtained with a 2D activation-based method. Effect of EGM quality was studied by discarding 3D phase reentries detected in regions with low-quality EGMs. Removal of reentries identified by 3D phase analysis in regions with low-quality EGMs improved its performance, increasing the area under the ROC curve (AUC) from 0.69 to 0.80. The EGMs quality classification algorithm showed an accurate performance for EGM classification (AUC 0.94) and reentry detection (AUC 0.80). Automatic classification of EGM quality based on time and spectral signal parameters is feasible and accurate, avoiding the manual labelling. Discard of reentries identified in regions with automatically-detected poor-quality EGMs improved the specificity of the 3D phase-based method for AF driver identification.
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Affiliation(s)
| | - Andreu M Climent
- ITACA Institute, Universitat Politècnica de València, Spain; Cardiology Department, Hospital General Universitario Gregorio Marañón, IiSGM, CIBERCV, Spain
| | | | | | | | | | - Felipe Atienza
- Cardiology Department, Hospital General Universitario Gregorio Marañón, IiSGM, CIBERCV, Spain
| | | | - Miguel Rodrigo
- ITACA Institute, Universitat Politècnica de València, Spain.
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18
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Bellmann B, Zettwitz M, Lin T, Ruppersberg P, Guttmann S, Tscholl V, Nagel P, Roser M, Landmesser U, Rillig A. Velocity characteristics of atrial fibrillation sources determined by electrographic flow mapping before and after catheter ablation. Int J Cardiol 2019; 286:56-60. [PMID: 30773268 DOI: 10.1016/j.ijcard.2019.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/28/2019] [Accepted: 02/04/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Electrographic-Flow-(EGF)-Mapping is a novel method to identify Atrial Fibrillation (AF) drivers. Sources of excitation during AF can be characterized and monitored. OBJECTIVE The aim of this study was to evaluate the correlation between velocity of EGF around a respective AF source and its spatial variability (SV) and stability (SST). METHODS 25 patients with AF were included in this study (persistent: n = 24, long-standing persistent: n = 1; mean age 70 ± 8.3 years, male: n = 17). Focal impulse and Rotor-Mapping (FIRM) was performed in addition to pulmonary vein isolation. One-minute epochs of unipolar electrograms recorded via a 64-pole basket catheter in both atria were re-analyzed with EGF-Mapping. SST was calculated as the percentage of time in which a source was detected. RESULTS AF sources identified with EGF-Mapping show a wide range of SV during 1 min covering between 0.12% and 38% of the recorded basket-catheter surface. The 12 atria where the sources showed highest temporal stability (TS; between 34% and 97% of 1 min recorded) and those 12 with the lowest TS (between 11 and 20%) differed significantly in their velocities (17.8 el/s vs 12.2 el/s; p < 0.01). In 11 atria ablation caused an average decrease of TS by 47% and of velocity by 27% while SV more than doubled. CONCLUSION Less stable AF-sources with high spatial variability showed reduced excitation propagation velocity while stable AF sources displayed a high average velocity in their vicinity. Importantly, catheter ablation reduced stability of sources and velocity suggesting a role of these parameters in guidance of ablation. CONDENSED ABSTRACT Electrographic Flow (EGF)-Mapping is a novel method to identify Atrial Fibrillation (AF) drivers based on modeling of an electrical potential surface and subsequent flow analysis. Sources of excitation during AF can be characterized and monitored. The aim of this study was to evaluate the correlation between velocity of EGF around a respective AF source and its spatial variability and stability. Less stable AF sources with high spatial variability showed reduced excitation propagation velocity while very stable AF sources displayed a high average velocity in their vicinity. Catheter ablation reduced stability of sources and velocity.
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Affiliation(s)
- Barbara Bellmann
- Charité, Universitätsmedizin Berlin, University Hospital, Department of Cardiology, Germany; Uniklinik Köln, Department of Electrophysiology, Germany
| | - Marit Zettwitz
- Charité, Universitätsmedizin Berlin, University Hospital, Department of Cardiology, Germany
| | - Tina Lin
- Heartcare Victoria, Melbourne, Australia
| | | | - Selma Guttmann
- Charité, Universitätsmedizin Berlin, University Hospital, Department of Cardiology, Germany
| | - Verena Tscholl
- Charité, Universitätsmedizin Berlin, University Hospital, Department of Cardiology, Germany
| | - Patrick Nagel
- Charité, Universitätsmedizin Berlin, University Hospital, Department of Cardiology, Germany
| | - Mattias Roser
- Charité, Universitätsmedizin Berlin, University Hospital, Department of Cardiology, Germany
| | - Ulf Landmesser
- Charité, Universitätsmedizin Berlin, University Hospital, Department of Cardiology, Germany
| | - Andreas Rillig
- Charité, Universitätsmedizin Berlin, University Hospital, Department of Cardiology, Germany.
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19
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Lin R, Zeng C, Xu K, Wu S, Qin M, Liu X. Dispersion-guided ablation in conjunction with circumferential pulmonary vein isolation is superior to stepwise ablation approach for persistent atrial fibrillation. Int J Cardiol 2018; 278:97-103. [PMID: 30587415 DOI: 10.1016/j.ijcard.2018.12.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/25/2018] [Accepted: 12/18/2018] [Indexed: 12/26/2022]
Abstract
BACKGROUND Due to the lack of optimal ablation strategy, the success rate of persistent atrial fibrillation (AF) is still low. We hypothesize that a strategy that targeting pulmonary triggers and dispersion areas in atria improves prognosis of persistent AF. METHODS We prospectively enrolled 142 persistent AF patients admitted for catheter ablation. These patients were randomly assigned in a 1:1 ratio to ablation with circumferential pulmonary vein isolation (CPVI) + ablation of electrogram dispersion areas (71 patients, group A) or stepwise ablation strategy (71 patients, group B). RESULTS Procedural time and fluoroscopy time did not differ between group A and group B (204.6 ± 26.9 min vs 207.8 ± 26.3 min and 7.3 ± 1.3 min vs 7.1 ± 1.3 min, respectively, P > 0.05), however, radiofrequency delivery time in group A was significantly shorter than that in group B (70 ± 7.2 min vs 83.2 ± 9.1 min, P < 0.001). In total, 265 electrogram dispersion areas were identified in 67 patients, and the most prominent areas were roof, bottom, and inferoposterior wall. The rates of acute AF endpoint (including AF termination and AFCL elongation >30 ms) and termination in group A were significantly higher than that in group B (97.2% vs. 71.8% and 70.4% vs. 15.5%, respectively, P < 0.001). During a follow-up period of 204 ± 67 days, both AF-free and AF/AT-free survival in group A were significantly higher than that in group B (P = 0.012 and P = 0.014, respectively). CONCLUSION Dispersion-guided ablation in conjunction with CPVI is efficient, personalized, and accurate for persistent AF.
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Affiliation(s)
- Rongjie Lin
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Cong Zeng
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Kai Xu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Shaohui Wu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Mu Qin
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
| | - Xu Liu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
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20
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Rubenstein DS, Yin H, Azami SA. Compass Mapping, Double Potentials, Activation Patterns Can Identify and Track Rotational Activity Sites in the Left Atrium of Humans with Persistent Atrial Fibrillation. J Atr Fibrillation 2018; 11:2053. [PMID: 30505380 PMCID: PMC6244311 DOI: 10.4022/jafib.2053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 06/02/2018] [Revised: 06/28/2018] [Accepted: 07/25/2018] [Indexed: 11/10/2022]
Abstract
BACKGROUND Rotational circuits that occur between bipolar electrodes exhibit double potentials (DPs). It had been previously surmised that rotors could not be electrically tracked directly. PURPOSE Our purpose was twofold; first, to show that the use of compass mapping, one can regionally identify rotational activity; and second, to show that by combining simultaneous compass map recordings, standard narrow-adjacent bipolar, and unipolar recordings, that specific signature recording patterns emerge that allow one to identify the accurate time, location, and path of a rotational mechanism. METHODS This was an observational study in 20 patients with persistent atrial fibrillation in which the electrode configuration of a circular mapping catheter was changed to wide cross-circle electrode pairing (compass mapping). DPs were recorded and analyzed from 12 left atrial (LA) sites and identified electrical wavefront patterns and direction. A substudy analyzed transitions patterns with simultaneous narrow-adjacent bipolar and unipolar recordings. RESULTS Four wavefront patterns were identified: DPs, peripheral waves (PWs), distal peripheral waves and fibrillatory activity. DP wavefront patterns exhibited significantly shorter cycle lengths than PWs in 8 of 12 LA sites. Patients had 2.9± 2.1 regions that exhibited DPs. DPs of varying duration were found, few (25%) were of stable duration and location. Detailed electrical examination at the transition between a PW to a DP identified a highly consistent pattern of simultaneous reversal of activation sequence, a special form of Doppler effect for spiral waves as a rotor passes between 2 electrodes, and a ½ cycle drop-off of activation signals along the line of electrodes. CONCLUSION DP recordings in compass mode can provide a regional assessment for the existence of rotational activity. Simultaneous DP recordings in compass mode, narrow-adjacent bipolar, and unipolar recording provide an accurate assessment of the time, location, and path that a rotational mechanism breaches a perimeter of electrodes. Accurate time, location and path of perimeter breaches can be used to electrically track rotational mechanisms during atrial fibrillation.
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Affiliation(s)
- Donald S Rubenstein
- Greenville Health System, Greenville Health System, 701 Grove Road, Greenville, SC 29605
| | - Hang Yin
- Provident Sacred Heart Medical Center, 101 W 8th Ave, Spokane, WA 99204
| | - Sana A Azami
- Greenville Health System, 701 Grove Road, Greenville, SC 29605
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21
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Abstract
BACKGROUND Conflicting evidence exists on the efficacy of focal impulse and rotor modulation on atrial fibrillation ablation. A potential explanation is inaccurate rotor localization from multiple rotors coexistence and a relatively large (9-11mm) inter-electrode distance (IED) of the multi-electrode basket catheter. METHODS AND RESULTS We studied a numerical model of cardiac action potential to reproduce one through seven rotors in a two-dimensional lattice. We estimated rotor location using phase singularity, Shannon entropy and dominant frequency. We then spatially downsampled the time series to create IEDs of 2-30mm. The error of rotor localization was measured with reference to the dynamics of phase singularity at the original spatial resolution (IED=1mm). IED has a significant impact on the error using all the methods. When only one rotor is present, the error increases exponentially as a function of IED. At the clinical IED of 10mm, the error is 3.8mm (phase singularity), 3.7mm (dominant frequency), and 11.8mm (Shannon entropy). When there are more than one rotors, the error of rotor localization increases 10-fold. The error based on the phase singularity method at the clinical IED of 10mm ranges from 30.0mm (two rotors) to 96.1mm (five rotors). CONCLUSIONS The magnitude of error of rotor localization using a clinically available basket catheter, in the presence of multiple rotors might be high enough to impact the accuracy of targeting during AF ablation. Improvement of catheter design and development of high-density mapping catheters may improve clinical outcomes of FIRM-guided AF ablation.
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Affiliation(s)
- Konstantinos N Aronis
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Hiroshi Ashikaga
- Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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22
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Abstract
PURPOSE OF REVIEW Pulmonary vein (PV) isolation is the cornerstone of atrial fibrillation (AF) ablation. However, the long-term procedural outcome remains suboptimal and there is a frequent need for repeat ablation procedure, especially in patients with non-paroxysmal AF. The review article summarizes the rationales, recent evidences, and strategies of ablation of extra-PV sites and its clinical outcomes. RECENT FINDINGS It is a consensus that durable PV isolations are a definite therapy in patients with paroxysmal AF. In non-paroxysmal AF, many laboratories still believe that adequate substrate ablation outside PVs is definitely required. Empirical linear ablation is not recommended because of difficulty in achieving complete linear block, unless macro-reentry atrial tachycardia developed during procedure. Most of laboratories applied complex fractionated atrial electrogram (CFAE) ablation after PV isolation in non-paroxysmal AF, but the efficacy is limited in the long-term follow-up studies. A combined approach using CFAE, non-linear similarity, and phase mapping strategy to identify rotors or focal sources for substrate modification increases the ablation outcome, when compared to CFAE ablation alone. Provocative test with mapping of non-PV triggers is also recommended in all patients to improve long-term ablation success. Ablation beyond PV isolation is important, especially in non-paroxysmal AF patients, to modify the diseased atrial substrate and eliminate the non-PV triggers, which in turn improve the ablation outcome.
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Affiliation(s)
- Li-Wei Lo
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital; Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan
| | - Yenn-Jiang Lin
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital; Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan
| | - Shih-Lin Chang
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital; Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan
| | - Yu-Feng Hu
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital; Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan
| | - Fa-Po Chung
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital; Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan
| | - Shih-Ann Chen
- Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital; Institute of Clinical Medicine, and Cardiovascular Research Institute, National Yang-Ming University, 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan.
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23
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Baykaner T, Zografos TA, Zaman JAB, Pantos I, Alhusseini M, Navara R, Krummen DE, Narayan SM, Katritsis DG. Spatial relationship of organized rotational and focal sources in human atrial fibrillation to autonomic ganglionated plexi. Int J Cardiol 2017; 240:234-239. [PMID: 28433558 DOI: 10.1016/j.ijcard.2017.02.152] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 02/28/2017] [Indexed: 12/21/2022]
Abstract
BACKGROUND One approach to improve ablation for atrial fibrillation (AF) is to focus on physiological targets including focal or rotational sources or ganglionic plexi (GP). However, the spatial relationship between these potential mechanisms has never been studied. We tested the hypothesis that rotors and focal sources for AF may co-localize with ganglionated plexi (GP). METHODS We prospectively identified locations of AF rotors and focal sources, and correlated these to GP sites in 97 consecutive patients (age 59.9±11.4, 73% persistent AF). AF was recorded with 64-pole catheters with activation/phase mapping, and related to anatomic GP sites on electroanatomic maps. RESULTS AF sources arose in 96/97 (99%) patients for 2.6±1.4 sources per patient (left atrium: 1.7±0.9 right atrium: 1.1±0.8), each with an area of 2-3cm2. On area analyses, the probability of an AF source randomly overlapping a GP area was 26%. Left atrial sources were seen in 94 (97%) patients, in whom ≥1 source co-localized with GP in 75 patients (80%; p<0.05). AF sources were more likely to colocalize with left vs right GPs (p<0.05), and colocalization was more likely in patients with higher CHADS2VASc scores (age>65, diabetes; p<0.05). CONCLUSIONS This is the first study to demonstrate that clinically detected AF focal and rotational sources in the left atrium often colocalize with regions of autonomic innervation. Studies should define if the role of AF sources differs by their anatomical location.
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Affiliation(s)
- Tina Baykaner
- Division of Cardiology, Stanford University, Stanford, CA, USA.
| | | | | | - Ioannis Pantos
- Department of Cardiology, Athens Euroclinic, Athens, Greece
| | | | - Rachita Navara
- Division of Cardiology, Stanford University, Stanford, CA, USA
| | | | | | - Demosthenes G Katritsis
- Department of Cardiology, Athens Euroclinic, Athens, Greece; Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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24
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Rodrigo M, Climent AM, Liberos A, Fernández-Avilés F, Berenfeld O, Atienza F, Guillem MS. Highest dominant frequency and rotor positions are robust markers of driver location during noninvasive mapping of atrial fibrillation: A computational study. Heart Rhythm 2017; 14:1224-1233. [PMID: 28408329 DOI: 10.1016/j.hrthm.2017.04.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Indexed: 12/31/2022]
Abstract
BACKGROUND Dominant frequency (DF) and rotor mapping have been proposed as noninvasive techniques to guide localization of drivers maintaining atrial fibrillation (AF). OBJECTIVE The purpose of this study was to evaluate the robustness of both techniques in identifying atrial drivers noninvasively under the effect of electrical noise or model uncertainties. METHODS Inverse-computed DFs and phase maps were obtained from 30 different mathematical AF simulations. Epicardial highest dominant frequency (HDF) regions and rotor location were compared with the same inverse-computed measurements after addition of noise to the ECG, size variations of the atria, and linear or angular deviations in the atrial location inside the thorax. RESULTS Inverse-computed electrograms (EGMs) individually correlated poorly with the original EGMs in the absence of induced uncertainties (0.45 ± 0.12) and were worse with 10-dB noise (0.22 ± 0.11), 3-cm displacement (0.01 ± 0.02), or 36° rotation (0.02 ± 0.03). However, inverse-computed HDF regions showed robustness against induced uncertainties: from 82% ± 18% match for the best conditions, down to 73% ± 23% for 10-dB noise, 77% ± 21% for 5-cm displacement, and 60% ± 22% for 36° rotation. The distance from the inverse-computed rotor to the original rotor was also affected by uncertainties: 0.8 ± 1.61 cm for the best conditions, 2.4 ± 3.6 cm for 10-dB noise, 4.3 ± 3.2 cm for 4-cm displacement, and 4.0 ± 2.1 cm for 36° rotation. Restriction of rotor detections to the HDF area increased rotor detection accuracy from 4.5 ± 4.5 cm to 3.2 ± 3.1 cm (P <.05) with 0-dB noise. CONCLUSION The combination of frequency and phase-derived measurements increases the accuracy of noninvasive localization of atrial rotors driving AF in the presence of noise and uncertainties in atrial location or size.
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Affiliation(s)
- Miguel Rodrigo
- ITACA, Universitat Politècnica de València, Valencia, Spain
| | - Andreu M Climent
- ITACA, Universitat Politècnica de València, Valencia, Spain; Cardiology Department, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; CIBERCV, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares, Madrid, Spain
| | - Alejandro Liberos
- ITACA, Universitat Politècnica de València, Valencia, Spain; Cardiology Department, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; CIBERCV, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares, Madrid, Spain
| | - Francisco Fernández-Avilés
- Cardiology Department, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; CIBERCV, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares, Madrid, Spain; Facultad de Medicina. Universidad Complutense de Madrid, Madrid, Spain
| | - Omer Berenfeld
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan
| | - Felipe Atienza
- Cardiology Department, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; CIBERCV, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares, Madrid, Spain; Facultad de Medicina. Universidad Complutense de Madrid, Madrid, Spain.
| | - Maria S Guillem
- ITACA, Universitat Politècnica de València, Valencia, Spain.
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Ciaccio EJ, Biviano AB, Wan EY, Peters NS, Garan H. Development of an automaton model of rotational activity driving atrial fibrillation. Comput Biol Med 2017; 83:166-181. [PMID: 28282592 DOI: 10.1016/j.compbiomed.2017.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [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: 11/10/2016] [Revised: 02/13/2017] [Accepted: 02/21/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is difficult to treat effectively, owing to uncertainty in where to best ablate to eliminate arrhythmogenic substrate. A model providing insight into the electrical activation events would be useful to guide catheter ablation strategy. Method A two-dimensional, 576×576 node automaton was developed to simulate atrial electrical activity. The substrate field was altered by the presence of differing refractory period at varying locations. Fibrosis was added in the form of short, randomly positioned lines of conduction block. Larger areas of block were used to simulate ablation lesions. Anisotropy was imposed in a 2:1 ratio. A premature electrical impulse from one of four grid corners was utilized to initiate activation. RESULTS Rotational activity was uninducible when refractory patch dimensions were less than 20×20mm. For larger refractory regions, a single premature stimulus was capable of inducing an average of 1.19±1.10 rotors, which often formed near the patch edges. A maximum of 5 rotors formed when refractory patch dimensions approached the size of the entire left atrial virtual field. Rotors formed along a refractory patch edge, after wavefront arrival was delayed at turning points or due to the presence of a fiber cluster of sufficient size. However, rotational activity could also occur around a large fiber cluster without the need of spatially variable refractoriness. When obstacles to conduction were lacking in size, nascent rotors drifted and either extinguished, or stabilized upon anchoring at a sufficiently large fiber cluster elsewhere in the field. Transient rotors terminated when traversing a region with differing refractory periods, if no obstacle to conduction was present to sufficiently delay wavefront arrival beyond the longest refractory period. Other rotors were annihilated when a nearby rotor with faster spin rate gradually interrupted the activation pathway. Elimination of anchors by removal, or by simulated ablation over a sufficient region, prevented rotor onset at a particular location where it would otherwise form. CONCLUSIONS The presence of obstacles to conduction and spatial differences in refractory period are important parameters for initiating and maintaining rotational activity in this simulation of an atrial substrate.
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Affiliation(s)
- E J Ciaccio
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY, USA.
| | - A B Biviano
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - E Y Wan
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - N S Peters
- Department of Medicine, Cardiovascular Sciences, Imperial College London, London, UK
| | - H Garan
- Department of Medicine, Division of Cardiology, Columbia University College of Physicians and Surgeons, New York, NY, USA
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Kumagai K, Minami K, Kutsuzawa D, Oshima S. Evaluation of the characteristics of rotational activation at high-dominant frequency and complex fractionated atrial electrogram sites during atrial fibrillation. J Arrhythm 2017; 33:49-55. [PMID: 28217229 PMCID: PMC5300866 DOI: 10.1016/j.joa.2016.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 05/14/2016] [Accepted: 05/30/2016] [Indexed: 11/15/2022] Open
Abstract
Background High-dominant frequency (DF) and continuous complex fractionated atrial electrogram (CFAE) sites as surrogates for localized sources maintaining atrial fibrillation (AF) are potential AF ablation targets. This study aimed to evaluate the characteristics of a rotational activation at high-DF and continuous CFAE sites in AF patients. Methods Thirty-two consecutive AF patients (5 paroxysmal and 27 non-paroxysmal) underwent ablation using the NavX system. When AF continued after circumferential pulmonary vein isolation (PVI), high-DF sites of ≥8 Hz and continuous CFAE sites (fractionated intervals ≤50 ms) in the left (LA) and right (RA) atria were recorded using a high-density 20-pole circular mapping catheter for 5 s and ablated. Results The atrial electrogram characteristics during AF were assessed. A total of 2383 AF beats from 89 high-DF and 19 continuous CFAE sites were investigated. A rotational activation of high-DF and continuous CFAE sites was also observed at 4% and 3% of LA, and 4% and 4% of RA sites, respectively. However, rotational activation was identified in 29 (91%) of 32 patients (mean 3.0±2.6 beats per patient, 80% in the LA). Procedural endpoints were achieved in 26 (81%) of 32 patients: AF termination (n=2) and AF cycle length slowing of >10% (n=26). Conclusions Rotational activation could be identified in high-DF and continuous CFAE sites during AF, but the documentation was limited. Therefore, only limited effects of rotational activation ablation at high-DF and/or continuous CFAE sites following PVI could be concluded.
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Affiliation(s)
- Koji Kumagai
- Division of Cardiology, Gunma Prefectural Cardiovascular Center, Maebashi, Gunma, Japan
| | - Kentaro Minami
- Division of Cardiology, Gunma Prefectural Cardiovascular Center, Maebashi, Gunma, Japan
| | - Daisuke Kutsuzawa
- Division of Cardiology, Gunma Prefectural Cardiovascular Center, Maebashi, Gunma, Japan
| | - Shigeru Oshima
- Division of Cardiology, Gunma Prefectural Cardiovascular Center, Maebashi, Gunma, Japan
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King B, Porta-Sánchez A, Massé S, Zamiri N, Balasundaram K, Kusha M, Jackson N, Haldar S, Umapathy K, Nanthakumar K. Effect of spatial resolution and filtering on mapping cardiac fibrillation. Heart Rhythm 2017; 14:608-615. [PMID: 28104480 DOI: 10.1016/j.hrthm.2017.01.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Endocardial mapping tools use variable interelectrode resolution, whereas body surface mapping tools use narrow bandpass filtering (BPF) to map fibrillatory mechanisms established by high-resolution optical imaging. OBJECTIVE The purpose of this study was to study the effect of resolution and BPF on the underlying mechanism being mapped. METHODS Hearts from 14 healthy New Zealand white rabbits were Langendorff perfused. We studied the effect of spatial resolution and BPF on the location and characterization of rotors by comparing phase singularities detected by high-resolution unfiltered optical maps and of fibrillating myocardium with decimated and filtered maps with simulated electrode spacing of 2, 5, and 8 mm. RESULTS As we decimated the maps with 2-mm, 5-mm, and 8-mm interelectrode spacing, the mean ( ± SD) number of rotors detected decreased from 10.2 ± 9.6, 1.6 ± 3.2, and 0.2 ± 0.5, respectively. Lowering the resolution led to synthesized pseudo-rotors that may be inappropriately identified. Applying a BPF led to fewer mean phase singularities detected (248 ± 207 vs 333 ± 130; P<.01), giving the appearance of pseudo-spatial stability measured as translation index (with BPF 3.6 ± 0.4 mm vs 4.0 ± 0.5 mm without BPF; P<.01) and pseudo-temporal stability with longer duration (70.0 ± 17.6 ms in BPF maps vs 44.1 ± 6.6 ms in unfiltered maps; P<.001) than true underlying fibrillating myocardium mapped. CONCLUSION Electrode resolution and BPF of electrograms can result in distortion of the underlying electrophysiology of fibrillation. Newer mapping techniques need to demonstrate sensitivity analysis to quantify the degree of distortion before clinical use to avoid inaccurate electrophysiologic interpretation.
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Affiliation(s)
| | | | | | - Nima Zamiri
- University Health Network, Toronto, Ontario, Canada
| | | | - Marjan Kusha
- University Health Network, Toronto, Ontario, Canada
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28
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Abstract
Although considerable progress has been made in developing ablation approaches to cure atrial fibrillation (AF), outcomes are still suboptimal, especially for persistent and long-lasting persistent AF. In this topical review, we review the arrhythmia mechanisms, both reentrant and nonreentrant, that are potentially relevant to human AF at various stages/settings. We describe arrhythmia mapping techniques used to distinguish between the different mechanisms, with a particular focus on the detection of rotors. We discuss which arrhythmia mechanisms are likely to respond to ablation, and the challenges and prospects for improving upon current ablation strategies to achieve better outcomes.
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Affiliation(s)
| | - Zhilin Qu
- UCLA Cardiovascular Research Laboratory
| | - Kalyanam Shivkumar
- Cardiac Arrhythmia Center & Neurocardiology Research Center of Excellence, Departments of Medicine (Cardiology) and Physiology, David Geffen School of Medicine, University of California, Los Angeles, California
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Sasaki N, Okumura Y, Watanabe I, Madry A, Hamano Y, Nikaido M, Kogawa R, Nagashima K, Takahashi K, Iso K, Ohkubo K, Nakai T, Hirayama A. Localized rotors and focal impulse sources within the left atrium in human atrial fibrillation: A phase analysis of contact basket catheter electrograms. J Arrhythm 2016; 32:141-4. [PMID: 27092196 PMCID: PMC4823606 DOI: 10.1016/j.joa.2015.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/11/2015] [Accepted: 11/27/2015] [Indexed: 12/05/2022] Open
Abstract
Background Consistent detection of rotor(s) and/or focal impulse(s) of atrial fibrillation can using a 64-pole basket catheter remain unclear. Methods and results Intracardiac left atrial electrograms were recorded, prior to ablation, in 20 patients with atrial fibrillation. Unipolar electrograms, filtered at 0.1–300 Hz, were recorded and exported for an offline phase analysis. From the cohort, 8 of the 20 patients had analyzable data. Localized rotors were identified in 3 of these patients, with focal impulses detected in 4 patients. Conclusion Localized rotors and focal impulses can be identified on phase maps of atrial fibrillation in a small number of patients.
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Affiliation(s)
- Naoko Sasaki
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Yasuo Okumura
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Ichiro Watanabe
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | | | | | | | - Rikitake Kogawa
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Koichi Nagashima
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Keiko Takahashi
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Kazuki Iso
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Kimie Ohkubo
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Toshiko Nakai
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Atsushi Hirayama
- Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
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30
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Walters TE, Lee G, Spence S, Kalman JM. The effect of electrode density on the interpretation of atrial activation patterns in epicardial mapping of human persistent atrial fibrillation. Heart Rhythm 2016; 13:1215-20. [PMID: 26829116 DOI: 10.1016/j.hrthm.2016.01.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Mechanisms sustaining human persistent atrial fibrillation (AF) remain debated, with significant differences between high-density epicardial and global endocardial mapping studies. A key difference is the density of recording electrodes. OBJECTIVE We aimed to determine the differences in the prevalence of different atrial activation patterns, and specifically in the prevalence of rotational activations, with varying densities of bipolar electrodes. METHODS Epicardial mapping was performed in 10 patients undergoing cardiac surgery, with bipolar electrograms recorded using a triangular plaque (6.75 cm(2) area; 117 bipoles; 2.5-mm inter-bipole spacing) applied to the left atrial posterior wall or right atrial free wall. Dynamic wavefront mapping based on the timing of atrial electrograms was applied to 2 discrete 10-second AF segments. The spacing between bipolar electrode locations was increased from 2.5 × 3.5 mm in the horizontal and oblique directions to 5.0 × 3.5, 5.0 × 7.1, and 7.5 × 10.6 mm, with wavefront mapping repeated at each density. RESULTS As density reduced, there was a significant change in relative proportions of the various activation patterns (F=3.69; P < .001). Simple broad wavefront activations became more prevalent (20% ± 8% to 54% ± 8%; P < .05) and complex patterns became less prevalent (48% ± 8% to 9% ± 8%; P < .05) with reducing density. The prevalence of rotational activity declined with bipole density, from median 5.0% (range 0.9%-12.1%) to 0% (range 0%-1.5%) (P = .03). The largest change occurred between inter-bipole spacings of 5.0 × 3.5 and 5.0 × 7.1 mm. CONCLUSION Apparent activation patterns in persistent AF vary significantly with electrode density. Low density underestimates the prevalence of complex and rotational patterns. The largest difference occurs between an inter-bipole spacing of 5.0 × 3.5 and a spacing of 5.0 × 7.1 mm. This may have important implications for mapping technology design.
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Affiliation(s)
- Tomos E Walters
- Department of Cardiology, Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Geoffrey Lee
- Department of Cardiology, Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia
| | - Steven Spence
- Department of Cardiology, Royal Melbourne Hospital, Melbourne, Australia
| | - Jonathan M Kalman
- Department of Cardiology, Royal Melbourne Hospital, Melbourne, Australia; Department of Medicine, University of Melbourne, Melbourne, Australia.
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Hansen BJ, Zhao J, Csepe TA, Moore BT, Li N, Jayne LA, Kalyanasundaram A, Lim P, Bratasz A, Powell KA, Simonetti OP, Higgins RSD, Kilic A, Mohler PJ, Janssen PML, Weiss R, Hummel JD, Fedorov VV. Atrial fibrillation driven by micro-anatomic intramural re-entry revealed by simultaneous sub-epicardial and sub-endocardial optical mapping in explanted human hearts. Eur Heart J 2015; 36:2390-401. [PMID: 26059724 DOI: 10.1093/eurheartj/ehv233] [Citation(s) in RCA: 280] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 05/08/2015] [Indexed: 11/12/2022] Open
Abstract
AIMS The complex architecture of the human atria may create physical substrates for sustained re-entry to drive atrial fibrillation (AF). The existence of sustained, anatomically defined AF drivers in humans has been challenged partly due to the lack of simultaneous endocardial-epicardial (Endo-Epi) mapping coupled with high-resolution 3D structural imaging. METHODS AND RESULTS Coronary-perfused human right atria from explanted diseased hearts (n = 8, 43-72 years old) were optically mapped simultaneously by three high-resolution CMOS cameras (two aligned Endo-Epi views (330 µm2 resolution) and one panoramic view). 3D gadolinium-enhanced magnetic resonance imaging (GE-MRI, 80 µm3 resolution) revealed the atrial wall structure varied in thickness (1.0 ± 0.7-6.8 ± 2.4 mm), transmural fiber angle differences, and interstitial fibrosis causing transmural activation delay from 23 ± 11 to 43 ± 22 ms at increased pacing rates. Sustained AF (>90 min) was induced by burst pacing during pinacidil (30-100 µM) perfusion. Dual-sided sub-Endo-sub-Epi optical mapping revealed that AF was driven by spatially and temporally stable intramural re-entry with 107 ± 50 ms cycle length and transmural activation delay of 67 ± 31 ms. Intramural re-entrant drivers were captured primarily by sub-Endo mapping, while sub-Epi mapping visualized re-entry or 'breakthrough' patterns. Re-entrant drivers were anchored on 3D micro-anatomic tracks (15.4 ± 2.2 × 6.0 ± 2.3 mm2, 2.9 ± 0.9 mm depth) formed by atrial musculature characterized by increased transmural fiber angle differences and interstitial fibrosis. Targeted radiofrequency ablation of the tracks verified these re-entries as drivers of AF. CONCLUSIONS Integrated 3D structural-functional mapping of diseased human right atria ex vivo revealed that the complex atrial microstructure caused significant differences between Endo vs. Epi activation during pacing and sustained AF driven by intramural re-entry anchored to fibrosis-insulated atrial bundles.
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Affiliation(s)
- Brian J Hansen
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Thomas A Csepe
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Brandon T Moore
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Ning Li
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Laura A Jayne
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Anuradha Kalyanasundaram
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA
| | - Praise Lim
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Anna Bratasz
- Small Animal Imaging Core, The Ohio State University Wexner Medical Center, Columbus, OH, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Kimerly A Powell
- Small Animal Imaging Core, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Orlando P Simonetti
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Robert S D Higgins
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ahmet Kilic
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Peter J Mohler
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Raul Weiss
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - John D Hummel
- Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Vadim V Fedorov
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, 300 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210-1218, USA Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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Abstract
Serum bilirubin measurements are commonly obtained for the evaluation of ill patients and to screen for liver disease in routine physical exams. An enormous research effort has identified the multiple mechanisms involved in the production and metabolism of conjugated (CB) and unconjugated bilirubin (UB). While the qualitative effects of these mechanisms are well understood, their expected quantitative influence on serum bilirubin homeostasis has received less attention. In this review, each of the steps involved in bilirubin production, metabolism, hepatic cell uptake, and excretion is quantitatively examined. We then attempt to predict the expected effect of normal and defective function on serum UB and CB levels in health and disease states including hemolysis, extra- and intrahepatic cholestasis, hepatocellular diseases (eg, cirrhosis, hepatitis), and various congenital defects in bilirubin conjugation and secretion (eg, Gilbert's, Dubin-Johnson, Crigler-Najjar, Rotor syndromes). Novel aspects of this review include: 1) quantitative estimates of the free and total UB and CB in the plasma, hepatocyte, and bile; 2) detailed discussion of the important implications of the recently recognized role of the hepatic OATP transporters in the maintenance of CB homeostasis; 3) discussion of the differences between the standard diazo assay versus chromatographic measurement of CB and UB; 4) pharmacokinetic implications of the extremely high-affinity albumin binding of UB; 5) role of the enterohepatic circulation in physiologic jaundice of newborn and fasting hyperbilirubinemia; and 6) insights concerning the clinical interpretation of bilirubin measurements.
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Affiliation(s)
- David G Levitt
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Michael D Levitt
- Research Service, Veterans Affairs Medical Center, Minneapolis, MN, USA
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Guan X, Zhang J, Rasselkorde EM, Abbasi WA, Kevin Zhou S. Material damage diagnosis and characterization for turbine rotors using three-dimensional adaptive ultrasonic NDE data reconstruction techniques. Ultrasonics 2014; 54:516-525. [PMID: 23978617 DOI: 10.1016/j.ultras.2013.07.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 06/11/2013] [Accepted: 07/31/2013] [Indexed: 06/02/2023]
Abstract
Damage diagnosis for turbine rotors plays an essential role in power plant management. Ultrasonic non-destructive examinations (NDEs) have increasingly been utilized as an effective tool to provide comprehensive information for damage diagnosis. This study presents a general methodology of damage diagnosis for turbine rotors using three-dimensional adaptive ultrasonic NDE data reconstruction techniques. Volume reconstruction algorithms and data fusion schemes are proposed to map raw ultrasonic NDE data back to the structural model of the object being examined. The reconstructed volume is used for automatic damage identification and quantification using region-growing algorithms and the method of distance-gain-size. Key reconstruction parameters are discussed and suggested based on industrial experiences. A software tool called AutoNDE Rotor is developed to automate the overall analysis workflow. Effectiveness of the proposed methods and AutoNDE Rotor are explored using realistic ultrasonic NDE data.
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Affiliation(s)
- Xuefei Guan
- Siemens Corporation, Corporate Technology, 755 College Rd. E., Princeton, NJ 08540, USA.
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34
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Sehra R, Narayan SM, Hummel J. Thinking outside the Box: Rotor Modulation in the Treatment of Atrial Fibrillation. J Atr Fibrillation 2013; 6:811. [PMID: 28496853 PMCID: PMC5153062 DOI: 10.4022/jafib.811] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/16/2013] [Accepted: 04/20/2013] [Indexed: 06/07/2023]
Abstract
Ablation for atrial fibrillation (AF) is an important and exciting therapy whose results remain suboptimal. Although most clinical trials show that ablation eliminates AF more effectively than medications, it is disappointing that the continued single procedural success remains ≈50% despite the substantial advances that have taken place in imaging, catheter positioning and energy delivery. Focal impulse and rotor modulation (FIRM), on the other hand, offers the opportunity to precisely define and then ablate patient-specific sustaining mechanisms for AF, rather than trying to eliminate all possible AF triggers. For over a decade, electrophysiologists have described cases in which AF terminates after only limited ablation - usually that cannot be explained by 'random' meandering wavelets. Indeed, recent studies from several laboratories show that all forms of clinical AF are typically 'driven' by stable electrical rotors and focal sources, not by multiple meandering waves. FIRM mapping enables an operator to place a catheter at typically 1-3 predicted sites in the atria, and with <5-10 minutes of RF ablation, terminate AF and potentially render it non-inducible. Several independent laboratories have now shown that such FIRM ablation alone can terminate or substantially slow AF in >80% of patients with persistent and paroxysmal AF and increase the single procedure rate of AF elimination from 50% with PV isolation alone to >80%. Ongoing studies hint that FIRM only ablation, enabling ablation times in the range observed for typical atrial flutter, may also achieve these high success rates without subsequent trigger ablation. This review summarizes the current state-of-the-art on FIRM mapping and ablation.
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Affiliation(s)
- Ruchir Sehra
- San Diego Veterans Administration Medical Center, La Jolla, CA and University of California, San Diego
| | - Sanjiv M Narayan
- San Diego Veterans Administration Medical Center, La Jolla, CA and University of California, San Diego
| | - John Hummel
- The Ohio State University Medical Center, Columbus, OH
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