Global versus local linear beat-to-beat analysis of the relationship between arterial pressure and pulse transit time during dynamic exercise
- 107 Downloads
Global linear analysis has been traditionally performed to verify the relationship between pulse transit time (PTT) and systolic arterial pressure (SAP) at the level of their spontaneous beat-to-beat variabilities: PTT and SAP have been plotted in the plane (PTT,SAP) and a significant linear correlation has been found. However, this relationship is weak and in specific individuals cannot be found. This result prevents the utilization of the SAP–PTT relationship to derive arterial pressure changes from PTT measures on an individual basis. We propose a local linear approach to study the SAP–PTT relationship. This approach is based on the definition of short SAP–PTT sequences characterized by SAP increase (decrease) and PTT decrease (increase) and on their search in the SAP and PTT beat-to-beat series. This local approach was applied to PTT and SAP series derived from 13 healthy humans during incremental supine dynamic exercise (at 10, 20 and 30% of the nominal individual maximum effort) and compared to the global approach. While global approach failed in some subjects, local analysis allowed the extraction of the gain of the SAP–PTT relationship in all subjects both at rest and during exercise. When both local and global analyses were successful, the local SAP–PTT gain is more negative than the global one as a likely result of noise reduction.
KeywordsPulse transit time Arterial pressure Dynamic exercise Cardiovascular variability
- 2.Bertinieri G, di Rienzo M, Cavallazzi A, Ferrari AU, Pedotti A, Mancia G (1985) A new approach to analysis of the arterial baroreflex. J Hypertens 3:S79–S81Google Scholar
- 3.Bland M (2000) An introduction to medical statistics. Oxford University Press, New YorkGoogle Scholar
- 8.Laude D, Elghozi JL, Girard A, Bellard F, Bouhaddi M, Castiglioni P, Cerutti C, Cividjian A, di Rienzo M, Fortrat JO, Janssen B, Karemaker JM, Leftheriotis G, Parati G, Persson PB, Porta A, Quintin L, Regnard J, Rudiger H, Stauss HM (2004) Comparison of various techniques used to estimate spontaneous baroreflex sensitivity (the EuroBaVar study). Am J Physiol 286:R226–R231Google Scholar
- 13.Porta A, Gasperi C, Nollo G, Lucini D, Antolini R, Pagani M (2005) Sequence analysis of pulse transit time and systolic blood pressure during dynamic exercise. In: Computers in cardiology 2005, Lyon, France, 25–28 September 2005Google Scholar