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. 2006 Oct 27;6(1):24–31. doi: 10.1111/j.1542-474X.2001.tb00082.x

Reproducibility of QT Parameters Derived from 24‐hour Ambulatory ECG Recordings in Healthy Subjects

Hanne Arildsen 1,✉, Evald Høj Christiansen 1, Anders Kirstein Pedersen 1, Henning Møgaard 1
PMCID: PMC7027613  PMID: 11174859

Abstract

Aim: To estimate the reproducibility of QT parameters derived from 24‐hour ambulatory ECG recordings.

Method: Ten healthy volunteers aged 25 to 41 years participated. In two 24‐hour ambulatory ECG recordings obtained 1 day apart, the QT interval was measured manually at stable heart rates in approximately 16 periods during daytime and 6 periods during nighttime. The association between the QT and RR interval was described by linear regression for day and nighttime separately and the following QT parameters were calculated: the QT interval at heart rate 60 beats/min during daytime (QT(60)day), slope(day), slope(night), and the difference in QT(60) between day and nighttime (ΔQT(60)). The QT parameters were assessed four times for each participant to discriminate method inaccuracy from day to day variation. The reproducibility was estimated as the coefficient of repeatability, the relative error, and the ratio between within‐subject variability and between‐subject variability.

Results: The coefficient of repeatability, the relative error and the ratio, respectively, were 19 ms, 1.8% and 0.5 for QT(60)day, 0.076, 21% and 0.68 for slope(day), 0.116, 43% and 1.37 for slope(night), and 37 ms, 325% and 1.19 for ΔQT(60) when estimating the overall day to day reproducibility. Inaccuracy of QT measurement accounted for approximately 40% of this variation, whereas the error caused by selecting segments was small.

Conclusion: QT(60)day has a high reproducibility and may with advantage replace the conventional QT interval measured on a resting ECG. To assess QT dynamics, the slope of the regression line during daytime is suitable and the short term reproducibility acceptable for clinical trials. Regarding slope(night) and ΔQT(60), the variation is high and the parameters should be used with caution. A.N.E. 2001;6(1):24–31

Keywords: reproducibility, QT interval, QT dynamics, ambulatory ECG recording

REFERENCES

  • 1. Schouten EG, Dekker JM, Meppelink P, et al. QT interval prolongation predicts cardiovascular mortality in an apparently healthy population. Circulation 1991;84:1516–1523. [DOI] [PubMed] [Google Scholar]
  • 2. de Bruyne MC, Hoes AW, Kors JA, et al. Prolonged QT interval predicts cardiac and all‐cause mortality in the elderly. The Rotterdam Study. Eur Heart J 1999;20: 278–284. [DOI] [PubMed] [Google Scholar]
  • 3. Algra A, Tijssen JG, Roelandt JR, et al. QTc prolongation measured by standard 12‐lead electrocardiography is an independent risk factor for sudden death due to cardiac arrest. Circulation 1991;83:1888–1894. [DOI] [PubMed] [Google Scholar]
  • 4. Ahnve S, Vallin H. Influence of heart rate and inhibition of autonomic tone on the QT interval. Circulation 1982;65:435–439. [DOI] [PubMed] [Google Scholar]
  • 5. Murakawa Y, Inoue H, Nozaki A, et al. Role of sympathovagal interaction in diurnal variation of QT interval. Am J Cardiol 1992;69:339–343. [DOI] [PubMed] [Google Scholar]
  • 6. Shimono M, Fujiki A, Asahi T, et al. Alterations in QT‐RR relationship in diabetic patients with autonomic dysfunction. Ann Noninvas Electrocardiol 1999;4:176–183. [Google Scholar]
  • 7. Fei L, Statters DJ, Gill JS, et al. Alteration of the QT/RR relationship in patients with idiopathic ventricular tachycardia. PACE 1994;17:199–206. [DOI] [PubMed] [Google Scholar]
  • 8. Tavernier R, Jordaens L, Haerynck F, et al. Changes in the QT interval and its adaptation to rate, assessed with continuous electrocardiographic recordings in patients with ventricular fibrillation, as compared to normal individuals without arrhythmias. Eur Heart J 1997;18:994–999. [DOI] [PubMed] [Google Scholar]
  • 9. Neyroud N, Maison‐Blance P, Denjoy I, et al. Diagnostic performance of QT interval variables from 24‐h electrocardiography in the long QT syndrome. Eur Heart J 1998;19:158–165. [DOI] [PubMed] [Google Scholar]
  • 10. Copie X, Alonso C, Lavergne T, et al. Reproducibility of QT interval measurements obtained from 24‐hour digitized ambulatory three‐lead electrocardiograms in patients with acute myocardial infarction and healthy volunteers. Ann Noninvas Electrocardiol 1998;3:38–45. [Google Scholar]
  • 11. Molnar J, Rosenthal JE, Weiss JS, et al. QT interval dispersion in healthy subjects and survivors of sudden cardiac death: circadian variation in a twenty‐four‐hour assessment. Am J Cardiol 1997;79:1190–1193. [DOI] [PubMed] [Google Scholar]
  • 12. Mølgaard H, Christensen PD, Sorensen KE, et al. Association of 24‐h cardiac parasympathetic activity and degree of nephropathy in IDDM patients. Diabetes 1992;41:812–817. [DOI] [PubMed] [Google Scholar]
  • 13. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1:307–310. [PubMed] [Google Scholar]
  • 14. Lawrence GP, Home PD, Murray A. Repeatability of measurements and sources of variability in tests of cardiovascular autonomic function. Br Heart J. 1992;68: 205–211. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15. Malik M, Kulakowski P, Poloniecki J. et al. Frequency versus time domain analysis of signal‐averaged electrocardiograms. I. Reproducibility of the results. J Am Coll Cardiol 1992;20: 127–134. [DOI] [PubMed] [Google Scholar]
  • 16. Schwartz PJ, Priori SG, Locati EH, et al. Long QT syndrome patients with mutations of the SCN5A and HERG genes have differential responses to Na+ channel blockade and to increases in heart rate. Implications for gene‐specific therapy. Circulation 1995;92: 3381–3386. [DOI] [PubMed] [Google Scholar]
  • 17. Kautzner J, Yi G, Camm AJ, et al. Short‐ and long‐term reproducibility of QT, QTc, and QT dispersion measurement in healthy subjects. Pacing Clin Electrophysiol 1994;17:928–937. [DOI] [PubMed] [Google Scholar]
  • 18. Glancy JM, Weston PJ, Bhullar HK, et al. Reproducibility and automatic measurement of QT dispersion. Eur Heart J 1996;17:1035–1039. [DOI] [PubMed] [Google Scholar]
  • 19. Toivonen L, Helenius K, Viitasalo M. Electrocardiographic repolarization during stress from awakening on alarm call. J Am Coll Cardiol 1997;30:774–779. [DOI] [PubMed] [Google Scholar]
  • 20. Stramba‐Badiale M, Locati EH, Martinelli A, et al. Gender and the relationship between ventricular repolarization and cardiac cycle length during 24‐h Holler recordings. Eur Heart J 1997;18:1000–1006. [DOI] [PubMed] [Google Scholar]
  • 21. Coumel P, Maison‐Blanche P, Catuli D, et al. Different circadian behavior of the apex and the end of the T wave. J Electrocardiol 1995;28(Suppl):138–142. [DOI] [PubMed] [Google Scholar]
  • 22. Molnar J, Weiss J, Zhang F, et al. Evaluation of five QT correction formulas using a software‐assisted method of continuous QT measurement from 24‐hour Holter recordings. Am J Cardiol 1996;78:920–926. [DOI] [PubMed] [Google Scholar]
  • 23. Cappato R, Alboni P. Pedroni P, et al. Sympathetic and vagal influences on rate‐dependent changes of QT interval in healthy subjects. Am J Cardiol 1991;68:1188–1193. [DOI] [PubMed] [Google Scholar]
  • 24. Cappato R, Alboni P. Codeca L, et al. Direct and autonomically mediated effects of oral quinidine on RR/QT relation after an abrupt increase in heart rate. J Am Coll Cardiol 1993;22:99–105. [DOI] [PubMed] [Google Scholar]
  • 25. Anselme F, Maison‐Blanche P, Cheruy P, et al. Absence of gender difference in circadian trends of QT interval duration. Ann Noninvas Electrocardiol 1996;1:278–286. [Google Scholar]
  • 26. Coumel P, Fayn J, Maison‐Blanche P, et al. Clinical relevance of assessing QT dynamicity in Hoiter recordings. J Electrocardiol 1994;27 (Suppl.):62–66. [DOI] [PubMed] [Google Scholar]
  • 27. Viitasalo M, Karjalainen J. QT intervals at heart rates from 50 to 120 beats per minute during 24‐hour electrocardiographic recordings in 100 healthy men. Effects of atenolol. Circulation 1992;86: 1439–1442. [DOI] [PubMed] [Google Scholar]

Articles from Annals of Noninvasive Electrocardiology are provided here courtesy of International Society for Holter and Noninvasive Electrocardiology, Inc. and Wiley Periodicals, Inc.

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