Medical & Biological Engineering & Computing

, Volume 37, Issue 1, pp 71–79

QT interval analysis on ambulatory electrocardiogram recordings: a selective beat averaging approach

  • F. Badilini
  • P. Maison-Blanche
  • R. Childers
  • P. Coumel
Physiological Signal Analysis


A computerised method for the analysis of QT intervals in ambulatory ECG recordings is presented. This approach is based on selective beat averaging which allows one to process P-QRS-T complexes together with the environment that characterises them. Long-term autonomic nervous system influences are accounted for by separating the analysis over different circadian periods. Effects of QT recovery time are taken into account by requiring a stable heart rate preceding each beat to be averaged. Before averaging, beats are resampled and realigned with respect to the R-wave peak estimated by parabolic interpolation. Averaged ECG templates are then analysed with an algorithm which automatically detects QRS complex and T-wave features. Repolarisation analysis is based on first and second derivatives of lowpass filtered ECG (recursive Butterworth filter). The QT/RR relationship and the circadian QT variation at identical heart rate were analysed in 14 normal individuals. When performed at stable heart rate conditions and when confined to well-defined circadian periods, the QT/RR relationship was strongly linear (r=0.95±0.06); in addition, the slope of this relation changed between day and night (respectively, 0.197±0.07 and 0.139±0.03, p<0.01). The range of circadian QT variation at identical heart rate was approximately 20 ms for both males and females.


QT interval Ambulatory ECG recordings Selective beat averaging QT/RR relation 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Albrecht, P., Cohen, R. J., andMark, R. G. (1988): ‘A stochastic characterization of chronic ventricular ectopic activity’,IEEE. Trans. Biomed. Eng.,35, pp. 539–550CrossRefGoogle Scholar
  2. Algra, A., Tijssen, J. G. P., Roelandt, J. R. T. C., Pool, J., andLubsen, J. (1993): ‘QT interval variables from 24-hour electrocardiography and the two year risk of sudden death’,Br. Heart J.,70, pp. 43–48CrossRefGoogle Scholar
  3. Altman, D. G., andGardner, M. J. (1988): ‘Calculating confidence intervals for regression and correlation’,Br. Med. J.,296, pp. 1238–1242CrossRefGoogle Scholar
  4. Berger, R. D., Kasper, E. K., Baughman, K. L., Marban, E., Calkins, H., andTomaselli, G. F. (1997): ‘Beat-to-Beat QT interval variability. Novel evidence for repolarization lability in ischemic and nonischemic dilated cardiomyopathy’,Circulation,96, pp. 1557–1565Google Scholar
  5. Bexton, R. S., Vallin, H. O., andCamm, A. J. (1986): ‘Diurnal variation of the QT interval-influence of the autonomic nervous system’,Br. Heart J.,55, pp. 253–258CrossRefGoogle Scholar
  6. Browne, K. F., Prystovsky, E., Heger, L. L., Chilson, D. A., andZipes, D. P. (1983): ‘Prolongation of the QT interval in man during sleep’,Am. J. Cardiol.,52, pp. 55–59CrossRefGoogle Scholar
  7. Christenson, D. W., Reddy, B. R. S., andRowlandson, G. I. (1989): ‘Evaluation of Fourier transform filter for high-resolution ECG’,J. Electrocardiol.,22, (suppl), pp. 33–40CrossRefGoogle Scholar
  8. Coumel, P., Leclercq, J. F., Zimmermann, M., andFunck-Brentano, J. L. (1987): ‘Antiarrhythmic therapy: noninvasive guided strategy versus empirical or invasive strategies’, inBrugada, P., andWellens, H. J. J. (Eds.): ‘Cardiac Arrhythmias: where to go from here?’ (Futura Publishing Company), pp. 403–419Google Scholar
  9. Extramiana, F., Huikkuri, H. V., Neyroud, N., Koistinen, J. M., Coumel, P., andMaison-Blanche, P. (1997): ‘QT Rate adaptation: a new index to discriminate patients with and without ventricular arrhythmias following myocardial infarction’,Circulation (abstract),96, 1–716Google Scholar
  10. Franz, M. R., Swerdlow, C. D., Liem, L. B., andSchaefer, J. (1988): ‘Cycle length dependence of human action potential duration in vivo: effects of single extrastimuli, sudden sustained rate acceleration and deceleration, and different steady state frequency’,J. Clin. Invest.,82, pp. 972–979CrossRefGoogle Scholar
  11. Funck-Brentano, C., Kibleur, Y., Le Coz, F., Poirier, J. M., Mallet, A., andJaillon, P. (1991): ‘Rate dependence of sotalol-induced prolongation of ventricular repolarization during exercise in humans’,Circulation,83, pp. 536–545Google Scholar
  12. Haissaguerre, M., Jais, P., Lavergne, T., Hocini, M., Takahashi, A., Barold, S. S., andClementy, J. (1998): ‘Mechanisms of spontaneous initiation of human atrial fibrillation’,Pace (abstract),21, 4(II) 1–49Google Scholar
  13. Hlatky, M. A., Boineau, R. E., Higginbotham, M. B., Lee, K. L., Mark, D. B., Califf, R. M., Cobb, F. R., andPryor, D. B. (1989): ‘A brief self-administered questionnaire to determine functional capacity (the Duke Activity Satatus Index)’,Am. J. Cardiol.,64, pp. 651–654CrossRefGoogle Scholar
  14. Laguna, P., Thakor, N. V., Caminal, P., Jané, R., Yoon, H. R., Bayes De Luna, A., Marti, V., andGuindo, J. (1990): ‘New algorithm for QT interval analysis in 24-hour Holter ECG: performance and applications’,Med. Biol. Eng. Comput.,28, pp. 67–73CrossRefGoogle Scholar
  15. Lepeschkin, E., andSurawicz, B. (1952): ‘The measurement of the Q-T interval of the electrocardiogram’,Circulation,51, pp. 378–388Google Scholar
  16. Locati, E. H., Maison-Blanche, P., Dejode, P., Cauchemez, B., andCoumel, P. (1995): ‘Spontaneous sequences of onset of torsade de pointes in patients with acquired prolonged repolarization quantitative analysis of Holter recordings’,J. Am. Coll. Cardiol.,25, pp. 1564–1575CrossRefGoogle Scholar
  17. Lombardi, F., Sandrone, G., Porta, A., Torzillo, D., Terranova, G., Baselli, G., Cerutti, S., andMalliani, A. (1996): ‘Spectral analysis of short term R-Tapex interval variability during sinus rhythm and fixed atrial rate’,Eur. Heart J.,17, pp. 769–778Google Scholar
  18. Merri, M., Farden, D. C., Mottley, J. G., andTitlebaum, E. L. (1990a): ‘Sampling frequency of the electrocardiogram for the spectral analysis of heart rate variability’,IEEE Trans. Biomed. Eng.,37, pp. 99–106CrossRefGoogle Scholar
  19. Merri, M., Alberti, M., Benhorin, J., andMoss, A. J. (1990b): ‘Preprocessing of Holter ECGs for analysis of the dynamic inter-relations between heart rate and ventricular repolarization duration variabilities’,J. Electrocardiol.,23 (Suppl), pp. 157–162CrossRefGoogle Scholar
  20. Merri, M., Moss, A. J., Benhorin, J., Locati, E. H., Alberti, M., andBadilini, F. (1992): ‘Relation between ventricular repolarization duration and cardiac cycle length during 24-hour Holter recording’,Circulation,85, pp. 1816–1821Google Scholar
  21. Murakawa, Y., Inoue, H., Nozaki, A., andSugimoto, T. (1992): ‘Role of sympathovagal interaction in diurnal variation of QT interval’,Am. J. Cardiol.,69, pp. 339–343CrossRefGoogle Scholar
  22. Murray, A., McLaughlin, N. B., Bourke, J. P., Doig, J. C., Furniss, S. S., andCampbell, R. W. F. (1994): ‘Errors in manual measurement of QT intervals’,Br. Heart J.,71, pp. 386–390CrossRefGoogle Scholar
  23. Narayanaswamy, S., Berbari, E. J., Lander, P., andLazzara, R. (1993): ‘Selective beat averaging and spectral analysis of beat intervals to determine the mechanisms of premature ventricular contractions’,in ‘Computers in cardiology’ Conf. (IEEE Computer Society Press), pp. 81–84Google Scholar
  24. Neyroud, N., Maison-Blanche, P., Denjoy, I., Chevret, S., Donger, S., Dausse, E., Fayn, J., Badilini, F., Menhabi, N., Schwartz, K., Guicheney, P., andCoumel, P. (1998): ‘Diagnostic performance of QT interval variables from 24-hour electrocardiography in the Long QT syndrome’,Eur. Heart J.,19, pp. 158–165CrossRefGoogle Scholar
  25. Oka, R. K., Gortner, S. R., Stotts, N. A., andHaskell, W. L. (1996): ‘Predictors of physical activity in patients with chronic heart failure secondary to either ischemic or idiopathic dilated cardiomyopathy’,Am. J. Cardiol.,77, pp. 159–163CrossRefGoogle Scholar
  26. Oppenheim, A. V., andShafer, R. W. (1989): ‘Discrete-time signal processing’ (Prentice Hall) Englewood Cliffs, New JerseyMATHGoogle Scholar
  27. Romberg, D., Patterson, H., Theres, H., Lander, P., Berbari, E. J., andBaumann, G. (1995): ‘Analysis of alternans in late potential’,J. Electrocardiol.,28 (Suppl), pp. 198–201CrossRefGoogle Scholar
  28. Ros, H. H., Koeleman, A. S. M., andAkker, T. J. (1981): ‘The technique of signal averaging and its practical application in the separation of atrial and His-Purkinje activity’,inHombach, V., andHilger, H. H. (Eds.): ‘Signal averaging technique in clinical cardiology: international symposium, Cologne, May 7–9, 1981’ (Shattauner Verlag), pp. 3–14Google Scholar
  29. Rosenbaum, D. S., Jackson, L. E., Smith, J. M., Garan, H., Ruskin, J. N., andCohen, R. J. (1994): ‘Electrical alternans and vulnerability to ventricular arrhythmias’,New England J. Med.,330, pp. 235–241CrossRefGoogle Scholar
  30. Sarma, J. S. M., Venkataraman, K., Samant, D. R., andCadgil, U. (1987): ‘Hysteresis in the human RR-QT relationship during exercise and recovery’,Pace,10, pp. 485–491Google Scholar
  31. Stramba-Badiale, M., Locati, E. H., Martinelli, A., Courville, J., andSchwartz, P. J. (1997): ‘Gender and the relationship between ventricular repolarization and cardiac cycle length during 24-h Holter recordings’,Eur. Heart J.,18, pp. 1000–1006Google Scholar
  32. Toivonen, L., Helenius, K., andVitasalo, M. (1997): ‘Electrocardiographic repolarization during stress from awakening on alarm call’,J. Am. Coll. Cardiol.,30, pp. 774–779CrossRefGoogle Scholar
  33. Verrier, R. L., Stone, P. H., Pace-Schott, E. F., andHobson, A. (1997): ‘Sleep related cardiovascular risk: new home-based monitoring technology for improved diagnosis and therapy’,A.N.A.,2(2), pp. 158–175Google Scholar
  34. Viskin, S., Heller, K., Barron, H. V., Kitzis, I., Hamdan, M., Olgin, J. E., Wong, M. J. Grant, S. E., andLesh, M. D. (1996): ‘Postextrasysystolic U wave augmentation, a new marker of increased arrhythmic risk in patients without the Long QT syndrome’,J. Am. Coll. Cardiol.,28, pp. 1746–1552CrossRefGoogle Scholar
  35. Zimmermann, M., Maison-Blanche, P., Cauchemez, B., Leclercq, J. F., andCoumel, P. (1986): ‘Determinants of the spontaneous ectopic activity in repetitive monomorphic idiopathic ventricular tachycardia’,J. Am. Coll. Cardiol.,7, pp. 1219–1227CrossRefGoogle Scholar

Copyright information

© IFMBE 1999

Authors and Affiliations

  • F. Badilini
    • 1
  • P. Maison-Blanche
    • 1
  • R. Childers
    • 2
  • P. Coumel
    • 1
  1. 1.Service de CardiologieHôpital LariboisièreParisFrance
  2. 2.Section of CardiologyThe University of Chicago Medical CenterChicagoUSA

Personalised recommendations