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Low-frequency blood flow oscillations in congestive heart failure and after beta1-blockade treatment.

Bernjak A, Clarkson PB, McClintock PV, Stefanovska A - Microvasc. Res. (2008)

Bottom Line: It is concluded that there are two oscillatory skin blood flow components associated with endothelial function.Both are reduced in CHF.Activity in the lower frequency interval is restored by beta(1)-blocker treatment, confirming the association between CHF and endothelial dysfunction but suggesting the involvement of two distinct mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Electrical Engineering, University of Ljubljana, Slovenia.

ABSTRACT
Laser Doppler flowmetry (LDF) of forearm skin blood flow, combined with iontophoretically-administered acetylcholine and sodium nitroprusside and wavelet spectral analysis, was used for noninvasive evaluation of endothelial function in 17 patients newly diagnosed with New York Heart Association class II-III congestive heart failure (CHF). After 20+/-10 weeks' treatment with a beta(1)-blocker (Bisoprolol), the measurements were repeated. Measurements were also made on an age- and sex-matched group of healthy controls (HC). In each case data were recorded for 30 min. In HC, the difference in absolute spectral amplitude of LDF oscillations between the two vasodilators manifests in the frequency interval 0.005-0.0095 Hz (p<0.01); this difference is initially absent in patients with CHF, but appears following the beta(1)-blocker treatment (p<0.01). For HC, the difference between the two vasodilators also manifests in normalised spectral amplitude in 0.0095-0.021 Hz (p<0.05). This latter difference is absent in CHF patients and is unchanged by treatment with beta(1)-blockers. It is concluded that there are two oscillatory skin blood flow components associated with endothelial function. Both are reduced in CHF. Activity in the lower frequency interval is restored by beta(1)-blocker treatment, confirming the association between CHF and endothelial dysfunction but suggesting the involvement of two distinct mechanisms.

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(a) The wavelet transform of an LDF skin blood flow signal, illustrating the presence of distinct spectral peaks whose frequencies and amplitudes vary in time. The wavelet coefficients, presented in the time–frequency domain, were calculated from the basal flow of a healthy subject at rest. Only a short time section of the transform is presented. (b) A time-average of the wavelet transform showing the division of the frequency scale into six intervals.
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fig2: (a) The wavelet transform of an LDF skin blood flow signal, illustrating the presence of distinct spectral peaks whose frequencies and amplitudes vary in time. The wavelet coefficients, presented in the time–frequency domain, were calculated from the basal flow of a healthy subject at rest. Only a short time section of the transform is presented. (b) A time-average of the wavelet transform showing the division of the frequency scale into six intervals.

Mentions: Computation of the wavelet transform of the blood flow signal yields the usual 3-dimensional structure above the time–frequency plane, exhibiting clearly resolved spectral peaks whose positions vary in time (Stefanovska et al., 1999; Stefanovska and Bračič, 1999) as shown in Fig. 2a, and a time-average as shown in Fig. 2b. The positions of the spectral peaks also differ slightly from subject to subject. In earlier work, based on 20-minute recordings, five frequency intervals were defined (Stefanovska et al., 1999; Stefanovska and Bračič, 1999) such that each of them contains only one peak: 0.0095–0.021, 0.021–0.052, 0.052–0.145, 0.145–0.6, and 0.6–1.6 Hz. They are attributed respectively to NO-dependent endothelial (Kvernmo et al., 1999; Stefanovska et al., 1999; Kvandal et al., 2003, 2006; Stewart et al., 2007), neurogenic (Kastrup et al., 1989; Söderström et al., 2003; Landsverk et al., 2006), myogenic (Kvernmo et al., 1999; Johnson, 1991; Bertuglia et al., 1994), respiratory and cardiac processes, as summarized in Table 2. The lowest detectable frequency component depends on the length of the signal and therefore longer recordings enabled investigations of blood flow spectrum below 0.0095 Hz. In the study of Kvandal et al. 30-minute LDF recordings were performed and an additional spectral peak centred near 0.007 Hz was observed and defined as the sixth frequency subinterval 0.005–0.0095 Hz (Kvandal et al., 2006). The physiological origin of this oscillation was investigated in the latter study and was shown to be related to endothelial activity, but not related to NO or prostaglandins. Therefore an endothelial regulatory process, different from that in the 0.0095–0.021 frequency interval, has been suggested.


Low-frequency blood flow oscillations in congestive heart failure and after beta1-blockade treatment.

Bernjak A, Clarkson PB, McClintock PV, Stefanovska A - Microvasc. Res. (2008)

(a) The wavelet transform of an LDF skin blood flow signal, illustrating the presence of distinct spectral peaks whose frequencies and amplitudes vary in time. The wavelet coefficients, presented in the time–frequency domain, were calculated from the basal flow of a healthy subject at rest. Only a short time section of the transform is presented. (b) A time-average of the wavelet transform showing the division of the frequency scale into six intervals.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2666799&req=5

fig2: (a) The wavelet transform of an LDF skin blood flow signal, illustrating the presence of distinct spectral peaks whose frequencies and amplitudes vary in time. The wavelet coefficients, presented in the time–frequency domain, were calculated from the basal flow of a healthy subject at rest. Only a short time section of the transform is presented. (b) A time-average of the wavelet transform showing the division of the frequency scale into six intervals.
Mentions: Computation of the wavelet transform of the blood flow signal yields the usual 3-dimensional structure above the time–frequency plane, exhibiting clearly resolved spectral peaks whose positions vary in time (Stefanovska et al., 1999; Stefanovska and Bračič, 1999) as shown in Fig. 2a, and a time-average as shown in Fig. 2b. The positions of the spectral peaks also differ slightly from subject to subject. In earlier work, based on 20-minute recordings, five frequency intervals were defined (Stefanovska et al., 1999; Stefanovska and Bračič, 1999) such that each of them contains only one peak: 0.0095–0.021, 0.021–0.052, 0.052–0.145, 0.145–0.6, and 0.6–1.6 Hz. They are attributed respectively to NO-dependent endothelial (Kvernmo et al., 1999; Stefanovska et al., 1999; Kvandal et al., 2003, 2006; Stewart et al., 2007), neurogenic (Kastrup et al., 1989; Söderström et al., 2003; Landsverk et al., 2006), myogenic (Kvernmo et al., 1999; Johnson, 1991; Bertuglia et al., 1994), respiratory and cardiac processes, as summarized in Table 2. The lowest detectable frequency component depends on the length of the signal and therefore longer recordings enabled investigations of blood flow spectrum below 0.0095 Hz. In the study of Kvandal et al. 30-minute LDF recordings were performed and an additional spectral peak centred near 0.007 Hz was observed and defined as the sixth frequency subinterval 0.005–0.0095 Hz (Kvandal et al., 2006). The physiological origin of this oscillation was investigated in the latter study and was shown to be related to endothelial activity, but not related to NO or prostaglandins. Therefore an endothelial regulatory process, different from that in the 0.0095–0.021 frequency interval, has been suggested.

Bottom Line: It is concluded that there are two oscillatory skin blood flow components associated with endothelial function.Both are reduced in CHF.Activity in the lower frequency interval is restored by beta(1)-blocker treatment, confirming the association between CHF and endothelial dysfunction but suggesting the involvement of two distinct mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Electrical Engineering, University of Ljubljana, Slovenia.

ABSTRACT
Laser Doppler flowmetry (LDF) of forearm skin blood flow, combined with iontophoretically-administered acetylcholine and sodium nitroprusside and wavelet spectral analysis, was used for noninvasive evaluation of endothelial function in 17 patients newly diagnosed with New York Heart Association class II-III congestive heart failure (CHF). After 20+/-10 weeks' treatment with a beta(1)-blocker (Bisoprolol), the measurements were repeated. Measurements were also made on an age- and sex-matched group of healthy controls (HC). In each case data were recorded for 30 min. In HC, the difference in absolute spectral amplitude of LDF oscillations between the two vasodilators manifests in the frequency interval 0.005-0.0095 Hz (p<0.01); this difference is initially absent in patients with CHF, but appears following the beta(1)-blocker treatment (p<0.01). For HC, the difference between the two vasodilators also manifests in normalised spectral amplitude in 0.0095-0.021 Hz (p<0.05). This latter difference is absent in CHF patients and is unchanged by treatment with beta(1)-blockers. It is concluded that there are two oscillatory skin blood flow components associated with endothelial function. Both are reduced in CHF. Activity in the lower frequency interval is restored by beta(1)-blocker treatment, confirming the association between CHF and endothelial dysfunction but suggesting the involvement of two distinct mechanisms.

Show MeSH
Related in: MedlinePlus