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Odening KE, van der Linde HJ, Ackerman MJ, Volders PGA, ter Bekke RMA. OUP accepted manuscript. Eur Heart J 2022; 43:3018-3028. [PMID: 35445703 PMCID: PMC9443984 DOI: 10.1093/eurheartj/ehac135] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
An abundance of literature describes physiological and pathological determinants of cardiac performance, building on the principles of excitation–contraction coupling. However, the mutual influencing of excitation–contraction and mechano-electrical feedback in the beating heart, here designated ‘electromechanical reciprocity’, remains poorly recognized clinically, despite the awareness that external and cardiac-internal mechanical stimuli can trigger electrical responses and arrhythmia. This review focuses on electromechanical reciprocity in the long-QT syndrome (LQTS), historically considered a purely electrical disease, but now appreciated as paradigmatic for the understanding of mechano-electrical contributions to arrhythmogenesis in this and other cardiac conditions. Electromechanical dispersion in LQTS is characterized by heterogeneously prolonged ventricular repolarization, besides altered contraction duration and relaxation. Mechanical alterations may deviate from what would be expected from global and regional repolarization abnormalities. Pathological repolarization prolongation outlasts mechanical systole in patients with LQTS, yielding a negative electromechanical window (EMW), which is most pronounced in symptomatic patients. The electromechanical window is a superior and independent arrhythmia-risk predictor compared with the heart rate-corrected QT. A negative EMW implies that the ventricle is deformed—by volume loading during the rapid filling phase—when repolarization is still ongoing. This creates a ‘sensitized’ electromechanical substrate, in which inadvertent electrical or mechanical stimuli such as local after-depolarizations, after-contractions, or dyssynchrony can trigger abnormal impulses. Increased sympathetic-nerve activity and pause-dependent potentiation further exaggerate electromechanical heterogeneities, promoting arrhythmogenesis. Unraveling electromechanical reciprocity advances the understanding of arrhythmia formation in various conditions. Real-time image integration of cardiac electrophysiology and mechanics offers new opportunities to address challenges in arrhythmia management.
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Affiliation(s)
| | - Henk J van der Linde
- Janssen Research & Development, Division of Janssen Pharmaceutica N.V., Beerse, Belgium
| | - Michael J Ackerman
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services (Windland Smith Rice Genetic Heart Rhythm Clinic), Mayo Clinic, Rochester, MN, USA
- Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA
- Department of Molecular Pharmacology & Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory), Mayo Clinic, Rochester, MN, USA
| | - Paul G A Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center+, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
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Nakayama S, Koie H, Kato-Tateishi M, Pai C, Ito-Fujishiro Y, Kanayama K, Sankai T, Yasutomi Y, Ageyama N. Establishment of a new formula for QT interval correction using a large colony of cynomolgus monkeys. Exp Anim 2019; 69:18-25. [PMID: 31308302 PMCID: PMC7004807 DOI: 10.1538/expanim.19-0009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The demand for monkeys for medical research is increasing, because their ionic mechanism
of repolarization is similar to that of humans. The QT interval is the distance between
the Q wave and T wave, but this interval is affected by heart rate. Therefore, QT
correction methods are commonly used in clinical settings. However, an accurate correction
formula for the QT interval in cynomolgus monkeys has not been reported. We assessed
snapshot electrocardiograms (ECGs) of 353 ketamine-immobilized monkeys, including aged
animals, and contrived a new formula for the corrected QT interval (QTc) as a marker of QT
interval prolongation in cynomolgus monkeys. Values for QTc were calculated using the
formula [QTc] = [QT] / [RR]n, along with several other formulas commonly used
to calculate QTc. We found that the optimal exponent of the QT interval corrected for
heart rate, n, was 0.576. The mean value of QTc in healthy monkeys determined using the
new formula was 373 ± 31 mm, and there were no significant differences between the sexes.
Other ECG parameters were not significantly different between the sexes and there were no
age-related effects on QTc. Prolongation of QTc to over 405 ms, as calculated by the new
formula, was observed in 50 monkeys with underlying diseases. Additionally, all monkeys
with QTc above 440 ms by the new formula had some underlying disease. The results resemble
those in humans, suggesting that the new QTc formula could be useful for diagnosis of QT
interval prolongation in cynomolgus monkeys.
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Affiliation(s)
- Shunya Nakayama
- Laboratory of Veterinary Physiology/Pathophysiology, Nihon University, College of Bioresource Science, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan.,Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, 1-1 Hachimandai, Tsukuba, Ibaraki 305-0843, Japan
| | - Hiroshi Koie
- Laboratory of Veterinary Physiology/Pathophysiology, Nihon University, College of Bioresource Science, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - Miyoko Kato-Tateishi
- The Corporation for Production and Research of Laboratory Primates, 1-16-2 Sakura, Tsukuba, Ibaraki 305-0003, Japan
| | - Chungyu Pai
- Laboratory of Veterinary Physiology/Pathophysiology, Nihon University, College of Bioresource Science, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan.,Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, 1-1 Hachimandai, Tsukuba, Ibaraki 305-0843, Japan
| | - Yasuyo Ito-Fujishiro
- Laboratory of Veterinary Physiology/Pathophysiology, Nihon University, College of Bioresource Science, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan.,Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, 1-1 Hachimandai, Tsukuba, Ibaraki 305-0843, Japan
| | - Kiichi Kanayama
- Laboratory of Veterinary Physiology/Pathophysiology, Nihon University, College of Bioresource Science, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan
| | - Tadashi Sankai
- Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, 1-1 Hachimandai, Tsukuba, Ibaraki 305-0843, Japan
| | - Yasuhiro Yasutomi
- Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, 1-1 Hachimandai, Tsukuba, Ibaraki 305-0843, Japan.,Mie University Graduate School of Medicine, Department of Molecular and Experimental Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
| | - Naohide Ageyama
- Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, 1-1 Hachimandai, Tsukuba, Ibaraki 305-0843, Japan
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Limprasutr V, Pirintr P, Kijtawornrat A, Hamlin RL. An increasing electromechanical window is a predictive marker of ventricular fibrillation in anesthetized rabbit with ischemic heart. Exp Anim 2017; 67:175-183. [PMID: 29162767 PMCID: PMC5955749 DOI: 10.1538/expanim.17-0100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The QTc interval is widely used in Safety Pharmacological studies to predict arrhythmia
risk, and the electromechanical window (EMW) and short-term variability of QT intervals
(STVQT) have been studied as new biomarkers for drug-induced Torsades de
Pointes (TdP). However, the use of EMW and STVQT to predict ventricular
fibrillation (VF) has not been elucidated. This study aimed to evaluate EMW and
STVQT to predict VF in anesthetized rabbit model of VF. VF was induced by
ligation of the left anterior descending and a descending branch of the left circumflex
coronary arteries in a sample population of rabbits (n=18). VF was developed 55.6%
(10/18). In rabbit with VF, the EMW was significantly higher than in rabbits without VF
(96.3 ± 15.6 ms and 49.5 ± 5.6 ms, respectively, P<0.05).
STVQT had significantly increased before the onset of VF in rabbits that
experienced VF, but not in rabbits that did not experience VF (11.7 ± 1.8 ms and 3.7 ± 0.4
ms, respectively, P<0.05). The EMW and STVQT had better
predictive power for VF with higher sensitivity and specificity than the QTc measure. The
result suggested that the increasing of EMW, as well as the elevation of STVQT,
can potentially be used as biomarkers for predicting of VF.
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Affiliation(s)
- Vudhiporn Limprasutr
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, 39 Henri Dunant Road, Wang Mai, Pathumwan, Bangkok 10330, Thailand
| | - Prapawadee Pirintr
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, 39 Henri Dunant Road, Wang Mai, Pathumwan, Bangkok 10330, Thailand.,Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, 155 Tumbon Mae Hiae, Muang, Chiang Mai 50100, Thailand
| | - Anusak Kijtawornrat
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, 39 Henri Dunant Road, Wang Mai, Pathumwan, Bangkok 10330, Thailand.,Research clusters: research study and testing of drug's effect related to cardiovascular system in laboratory animals, Chulalongkorn University, 39 Henri Dunant Road, Wang Mai, Pathumwan, Bangkok 10330, Thailand
| | - Robert L Hamlin
- QTest Labs, LLC. 6456 Fiesta Drive, Columbus, Ohio 43235, USA
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