Non-invasive assessment of human baroreflex during different body positions

Iida, Ryoji; Hirayanagi, Kaname; Iwasaki, Katsurô; Ogawa, Setsuro; Suzuki, Hajime; Yajima, Kazuyoshi

doi:10.1016/s0165-1838(98)00188-x

Cited by 26 publications

(29 citation statements)

References 16 publications

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“…1). The mean values of the BRS for the maneuvers were similar to those reported by other authors for supine position (Kardos et al 2001;Kim and Euler 1997), standing (Iida et al 1999;Kim and Euler 1997;Steptoe and Vo¨gele 1990), exercise (Pagani et al 1988), and recovery (Piepoli et al 1993). …”

Section: Discussionsupporting

confidence: 88%

“…For instance, although the sinoaortic denervation markedly reduced the BRS at respiratory frequency estimated by a-coefficient, there was a persistence of high coherence values (Mancia et al 1999). In support of the BRS evaluation in this frequency band we found: (a) strong log-log correlations between the high frequency and sequence technique (Table 3) and with the low-frequency figures (Table 3, Fig 4d), a result also reported by other authors (Iida et al 1999;Rü diger and Bald 2001), and (b) the BRS values in the high-frequency band have the same relationship with the vagal outflow that the low frequency estimates.…”

Section: Brs Values In the Frequency Bandssupporting

confidence: 88%

“…Although this may be regarded as a limitation, it is our position that our results would also be applicable to lowlanders, given that neither obvious differences in vagal activity nor BRS values, compared to lowlanders, under resting conditions have been observed (Seals et al 2001). Even more, our BRS estimates presented similar values to those reported (Kardos et al 2001;Kim and Euler 1997;Iida et al 1999;Pagani et al 1988;Steptoe and Vo¨gele 1990;Piepoli et al 1993) using the same techniques. A second limitation would be a possible lack of confidence on the validity of the absolute pressure values obtained from the Finapres.…”

Section: Limitationssupporting

confidence: 85%

“…The BRS values obtained in supine position have been used as reference (Kardos et al 2001;Tank et al 2000), but the shortcome being their large dispersion. Standing should be considered as a complementary condition to assess the BRS because of the following reasons: this maneuver is a representative condition of the baroreflex mechanism; the values provided by the different techniques are clustered around 7.3±2 ms mmHg À1 and are in accordance with other authors (Iida et al 1999;Kim and Euler 1997;Steptoe and Vo¨gele 1990); the differences between the low-and high-frequency BRS values vanish; the variation coefficient is 8% lower than for supine position; and with respect to supine, it presents a systematic behavior for the same individual, as depicted in Fig. 2.…”

Section: Limitationssupporting

confidence: 79%

“…Thus, some have reported similar BRS values among them (Di Rienzo et al 1997;Hughson and Quintin 1993;Iida et al 1999;Kim and Euler 1997;Parati et al 1995), while others have found significant differences (Gerritsen et al 2000;Porta et al 2000;Rü diger and Bald 2001;Tank et al 2000). The structure, origin, and occurrence rate of the systolic pressure patterns used by diverse BRS assessment techniques are markedly different; so in principle, they should lead to discrepancies on the BRS estimation (Di Rienzo et al 1997), although agreement has been found (Persson et al 2001).…”

Section: Effect Of the Maneuvers On The Brs Values By The Four Technimentioning

confidence: 96%

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Baroreflex sensitivity assessment and heart rate variability: relation to maneuver and technique

et al. 2005

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In the present study, we examined two baroreflex sensitivity (BRS) issues that remain uncertain: the differences among diverse BRS assessment techniques and the association between BRS and vagal outflow. Accordingly, the electrocardiogram and non-invasive arterial pressure were recorded in 27 healthy subjects, during supine with and without controlled breathing, standing, exercise, and recovery conditions. Vagal outflow was estimated by heart rate variability indexes, whereas BRS was computed by alpha-coefficient, transfer function, complex demodulation in low- and high-frequency bands, and by sequence technique. Our results indicated that only supine maneuvers showed significantly greater BRS values over the high frequency than in the low-frequency band. For maneuvers at the same frequency region, supine conditions presented a larger number of significant differences among techniques. The plots between BRS and vagal measures depicted a funnel-shaped relationship with significant log-log correlations (r=0.880-0.958). Very short latencies between systolic pressure and RR interval series in high-frequency band and strong log-log correlations between frequency bands were found. Higher variability among different baroreflex measurements was associated with higher level of vagal outflow. Methodological assumptions for each technique seem affected by non-baroreflex variation sources, and a modified responsiveness of vagal motoneurons due to distinct stimulation levels for each maneuver was suggested. Thus, highest vagal outflows corresponded to greatest BRS values, with maximum respiratory effect for the high-frequency band values. In conclusion, BRS values and differences across the tested techniques were strongly related to the vagal outflow induced by the maneuvers.

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