Skin Blood Flow and Its Oscillatory Components in Patients with Acute Myocardial Infarction

Abstract

Background/Aims: Laser Doppler flowmetry (LDF) was used to determine the influence of acute myocardial infarction (AMI) and of successful reperfusion treatment on basal skin blood flow and its oscillatory components. Methods: Skin LDF was performed on all extremities in 58 patients 4–9 days after AMI (Killip class I), and in 71 healthy age- and sex-matched controls. Wavelet analysis was applied to evaluate oscillatory components within the interval 0.005–2 Hz. Results: AMI patients had reduced mean flow (p < 0.01) and oscillatory components (p < 0.04) in all extremities. Reperfused (n = 40), compared to nonreperfused (n = 18), patients had higher mean flow and total spectral amplitude at all recording points. The difference was statistically significant only in legs (group median LDF in the left leg was 9.68 AU for reperfused and 5.71 AU for nonreperfused patients, p < 0.04, and 11.47 and 4.24 AU in the right leg, p < 0.01). Reperfused patients had significantly higher total spectral amplitude in both legs (p < 0.04). Conclusions: In AMI patients, reduced skin blood flow and its oscillatory components may reflect ongoing neurohumoral activation despite absence of clinically apparent heart failure. The reduction of blood flow and its oscillatory components was larger in nonreperfused AMI patients, although they had a comparable left ventricular function.

Low-frequency blood flow oscillations in congestive heart failure and after β1-blockade treatment

“…Unlike many earlier studies, our interest therefore centres on blood flow dynamics (Stefanovska and Bračič, 1999), rather than on basal values. The main advantage of this approach is that its frequency resolution enables the contributions from different physiological processes to be distinguished, and it has already been applied to other disease states related to the cardiovascular system: type 2 diabetes (Urbančič-Rovan et al, 2004) and post acute myocardial infarction (Ažman-Juvan et al, 2008). It was postulated that the difference in endothelial reactivity of the CHF group and an age-matched healthy control (HC) group will be manifested in particular oscillatory components.…”

Age‐related changes of skin blood flow during postocclusive reactive hyperemia in human

“…The oscillations, whose nature is diverse, reflect the current functional state of the regulatory systems that govern blood flow . There are six nonoverlapping intervals in the frequency range of 0.005–2 Hz: 0.005–0.0095 Hz – NO‐independent endothelial activity; 0.0095–0.021 Hz – NO‐dependent endothelial activity; 0.021–0.052 Hz – neurogenic activity; 0.052–0.145 Hz – myogenic activity; 0.145–0.6 Hz – respiratory rhythm; 0.6–2 Hz – cardiorhythm . In these intervals, the oscillations of blood flow are determined by the influence of endothelial , neurogenic , myogenic , respiratory ; and cardiac processes respectively.…”

Discussion of “Time-frequency Techniques in Biomedical Signal Analysis: A Tutorial Review of Similarities and Differences”

“…The wavelet transform has been used e.g. as a filter for de-noising single events [44] and to reveal endothelial dysfunction in diabetes mellitus [45], post-acute myocardial infarction [46], congestive heart failure [47], hypertension [48], and ageing [49,50]. Its great advantage lies in the possibility of logarithmic frequency resolution, enabling a very wide range of frequencies to be encompassed, a feature that is often essential in the analysis of physiological time series.…”