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Kusuki H, Mizutani Y, Tsuchiya Y, Nishio M, Oikawa S, Nagata R, Kiriyanagi Y, Horio K, Hosoi M, Matsuura H, Sadanaga T, Hata T. Myocardial repolarization time, J-point to T-peak and T-peak to T-end intervals, have different heart rate dependency and autonomic nerve interference in healthy prepubertal children. J Electrocardiol 2021; 67:119-123. [PMID: 34174541 DOI: 10.1016/j.jelectrocard.2021.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 02/27/2021] [Revised: 04/10/2021] [Accepted: 05/25/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The JT interval of the myocardial repolarization time can be divided into Jpoint to T-peak interval (JTp) and T-peak to T-end interval (Tpe). It is well known that the JT interval is dependent on the heart rate, but little is known regarding heart rate dependence for JTp and Tpe. The aim of the present study was to clarify the heart rate dependence of JTp and Tpe and to elucidate the interference of autonomic nervous activity with these parameters. METHODS We evaluated 50 prepubertal children (mean age: 6.4 ± 0.5 years; male:female, 22:28) without heart disease. JTp, Tpe, and the preceding RR intervals were measured using 120 consecutive beats (lead CM5). First, the relationships between the RR interval and JTp and Tpe were evaluated by Pearson's correlation coefficient. Second, to evaluate autonomic interference with JTp and Tpe, the degree of coherence between RR interval variability and JTp or Tpe variability was calculated using spectral analysis. RESULTS Significant positive correlations were observed between the RR interval and JTp (y = 0.116x + 105.5; r = 0.594, p < 0.001) and between the RR interval and Tpe (y = 0.037x + 44.7; r = 0.432, p < 0.001). Tpe variability had a lower degree of coherence with RR interval variability (range: 0.039-0.5 Hz) than with JTp variability (0.401 [interquartile range, 0.352-0.460] vs. 0.593 [0.503-0.664], respectively; p < 0.001). CONCLUSIONS Tpe had lower heart rate dependence and a lower degree of autonomic nervous interference than did JTp.
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Affiliation(s)
- Hirofumi Kusuki
- Graduate school of Health Science, Fujita Health University, Toyoake, Japan.
| | - Yuri Mizutani
- Clinical Laboratory Division, Fujita Health University Hospital, Toyoake, Japan
| | - Yuka Tsuchiya
- Graduate school of Health Science, Fujita Health University, Toyoake, Japan
| | - Miki Nishio
- Graduate school of Health Science, Fujita Health University, Toyoake, Japan
| | - Shota Oikawa
- Clinical Laboratory Division, Fujita Health University Hospital, Toyoake, Japan
| | - Rina Nagata
- Clinical Laboratory Division, Fujita Health University Hospital, Toyoake, Japan
| | - Yumi Kiriyanagi
- Clinical Laboratory Division, Fujita Health University Hospital, Toyoake, Japan
| | - Kayo Horio
- Department of Physiology, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Misa Hosoi
- Clinical Laboratory Division, Fujita Health University Hospital, Toyoake, Japan
| | - Hideaki Matsuura
- Graduate school of Health Science, Fujita Health University, Toyoake, Japan; Clinical Laboratory Division, Fujita Health University Hospital, Toyoake, Japan
| | | | - Tadayoshi Hata
- Graduate school of Health Science, Fujita Health University, Toyoake, Japan; Clinical Laboratory Division, Fujita Health University Hospital, Toyoake, Japan
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Boulay E, Troncy E, Accardi MV, Pugsley MK, Downey AM, Miraucourt L, Huang H, Menard A, Tan W, Dubuc-Mageau M, Sanfacon A, Guerrier M, Authier S. Confounders and Pharmacological Characterization When Using the QT, JTp, and Tpe Intervals in Beagle Dogs. Int J Toxicol 2020; 39:530-541. [PMID: 33063577 DOI: 10.1177/1091581820954865] [Citation(s) in RCA: 1] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Corrected QT (QTc) interval is an essential proarrhythmic risk biomarker, but recent data have identified limitations to its use. The J to T-peak (JTp) interval is an alternative biomarker for evaluating drug-induced proarrhythmic risk. The aim of this study was to evaluate pharmacological effects using spatial magnitude leads and DII electrocardiogram (ECG) leads and common ECG confounders (ie, stress and body temperature changes) on covariate adjusted QT (QTca), covariate adjusted JTp (JTpca), and covariate adjusted T-peak to T-end (Tpeca) intervals. METHODS Beagle dogs were exposed to body hyper- (42 °C) or hypothermic (33 °C) conditions or were administered epinephrine to assess confounding effects on heart rate corrected QTca, JTpca, and Tpeca intervals. Dofetilide (0.1, 0.3, 1.0 mg/kg), ranolazine (100, 140, 200 mg/kg), and verapamil (7, 15, 30, 43, 62.5 mg/kg) were administered to evaluate pharmacological effects. RESULTS Covariate adjusted QT (slope -12.57 ms/°C) and JTpca (-14.79 ms/°C) were negatively correlated with body temperature but Tpeca was minimally affected. Epinephrine was associated with QTca and JTpca shortening, which could be related to undercorrection in the presence of tachycardia, while minimal effects were observed for Tpeca. There were no significant ECG change following ranolazine administration. Verapamil decreased QTca and JTpca intervals and increased Tpeca, whereas dofetilide increased QTca and JTpca intervals but had inconsistent effects on Tpeca. CONCLUSION Results highlight potential confounders on QTc interval, but also on JTpca and Tpeca intervals in nonclinical studies. These potential confounding effects may be relevant to the interpretation of ECG data obtained from nonclinical drug safety studies with Beagle dogs.
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Affiliation(s)
- Emmanuel Boulay
- Charles River Laboratories, Laval, Quebec, Canada.,70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Eric Troncy
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | | | | | | | | | - Hai Huang
- Charles River Laboratories, Laval, Quebec, Canada
| | | | - Wendy Tan
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | | | - Audrey Sanfacon
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Mireille Guerrier
- 70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
| | - Simon Authier
- Charles River Laboratories, Laval, Quebec, Canada.,70354Faculté de médecine vétérinaire, Université de Montréal, Québec, Canada
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