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BackgroundAortic stenosis (AS) is commonly associated with myocardial and systemic arterial dysfunction. We use a radial artery applanation tonometry (B-Pro) device to characterise the arterial pulse profile of patients with AS and compare them against controls.MethodsThe B-Pro device was applied on the left radial artery of 117 consecutive patients, where 21 patients had AS. Baseline clinical and echocardiographic characteristics were compared. Differences in arterial pulse pressure profile were quantified by means of univariate and multivariable analyses.ResultsThe group with AS was older (74±14 vs 62±14 years, PConclusionThe B-Pro device allows for real-time microscopic arterial pulse waveform analysis. There are significant differences between the pulse profiles of patients with AS and controls. The prognostic implications of these differences warrant further study.

Newly gallo-titanogallate type K x Ga 8 Ga 8+x Sn 16−x O 56 (KGGSO) was prepared by a solid state reaction and a flux slow-cooling method for exploring its potential as an ionic conductor. KGGSO single crystals were obtained under the following conditions: crystal composition “C” (K 2 CO 3 ) 1 (Ga 2 O 3 ) 8 (SnO 2 ) 8 ; flux composition “F” (K 2 CO 3 ) 2 (MoO 3 ) 1 (B 2 O 3 ) 1 ; “C/F” = 20/80; cooling rate, 4 K/h (1623 K–1273 K). The crystal had a needle-like morphology and averaged about 2 mm length and 10 μm diameter. Structure refinement by single crystal X-ray diffraction showed reliability factors of R = 0.0961 and wR = 0.1481 under an isotropic condition. The lattice parameters of KGGSO (a = 1.8361(5) nm, c = 0.31280(9) nm) were larger than those of K 0.8 Ga 8 Ga 8.8 Ti 15.2 O 56 (KGGTO, a = 1.8135(2) nm, c = 0.29966(4) nm). The chemical composition of KGGSO based on site occupancy was K 1.436 Ga 8 Ga 8.764 Sn 15.236 O 56 . In examining the cause behind the inhomogeneous expansion of the lattice parameter, we speculated that the potassium ions in the unit cell increased for keeping the gallo-titanogallate structure by substituting tin for titanium, and the repulsion force among potassium ions increased along the one-dimensional tunnels. Also, the KGGSO powder prepared at 1623 K for 24 h showed a solid solution region of 1.2 ≤ x ≤ 1.5 under the initial composition condition.

The effect of mild depression on blood pressure (BP) was assessed in 116 Japanese (32–79 years). As compared to non-depressive (Geriatric Depression Scale, GDS-15 score

As a step towards investigating the chronome (i.e. the inferential endpoints of chaos, trends and rhythms) of heart rate (HR) variability (HRV), we investigated whether the fractality or complexity of HRV is affected by a head-up tilting (HUT) test in the morning after an overnight fast. Spectral and non-linear analyses of HR were performed on data gathered during an 80 degrees passive HUT test in 15 men and 28 women 32.8 +/- 11.5 years of age. The non-linear endpoints included the scaling exponents alpha1 (11 beats) and alpha2 (11 beats), which indicate fractal properties, calculated with detrended fluctuation analysis, and the approximate entropy (ApEn), a measure of overall complexity. Passive HUT increased alpha1 (from 0.986 +/- 0.217 to 1.370 +/- 0.185; P = 0.0001), but did not alter alpha2 (from 0.925 +/- 0.110 to 0.958 +/- 0.130; P = 0.19). A slight but statistically significant decrease in ApEn was seen during HUT (from 1.114 +/- 0.131 to 1.013 +/- 0.197; P = 0.002). In the tilt-up position, there was a statistically significant negative correlation between alpha1 and ApEn (r = -0.490; P0.05). In both the supine and the tilt-up position, alpha1 was correlated weakly with HF (r = -0.343 and r = -0.322, respectively), and strongly with LF/HF (r = 0.557 and r = 0.795), respectively. There was also a negative correlation between ApEn and LF/HF (r = -0.406 and r = -0.357, respectively). alpha2 did not correlate with any spectral or non-linear measures of HRV. Short-term fractal properties and complexity of HR were lowered with orthostatic stress. Alterations of the autonomic activities could be partly responsible for these changes and await extension of such studies to assess the broad spectral element of HRV, that includes, with components of approximately 3.6 and approximately 10.5 s, cycles with very much lower frequencies, along the scales of hours and even years, that critically modulate the mislabeled (only relatively high- and low-frequency) components in the range of seconds or minutes.

It is becoming recognized that geomagnetic activity may influence biological processes, including the incidence of various human diseases. There is evidence that heart rate variability (HRV) may serve not only as an index of autonomic coordination of the circulation, but also as a powerful predictor of risk in apparently healthy subjects. This study focuses on the effects of geomagnetic disturbance on HRV, by comparing different indices of HRV of young, healthy men living in a subarctic area on days of low (Ap; 0-7), middle (Ap; 7-20), and high (Ap; 20-45) geomagnetic activity. The effect of geomagnetic disturbance on HRV is examined on the basis of 7-day records by Holter ECG, obtained longitudinally on 5 clinically healthy men, 21-31 years of age, in Alta, Norway (70 degree N). Frequency- and time-domain measures of HRV were analyzed for each subject on separate 24-hour spans. A graded alteration of HRV endpoints was found in association with increased geomagnetic activity. As time-domain measures of HRV, SDNNIDX and the 90% length of the Lorenz plot decreased statistically significantly on days with increased geomagnetic disturbance (p = 0.0144 and p = 0.0102, respectively). A graded decrease in frequency-domain HRV measures was also validated statistically for the total spectral power (decrease of 18.1% and 31.6% on days when 7 < Ap < 20 and 20 < Ap < 45 versus days when Ap < 7; p = 0.0013). The decrease in spectral power was mainly found at frequencies below 0.04 Hz, in the "ultra-low-frequency" (0.0001-0.003 Hz; 18.1% and 27.5% decrease, respectively; p = 0.0102) and "very-low-frequency" (0.003-0.04 Hz; 12.9% and 28.6% decrease, respectively; p = 0.0209) regions of the spectrum. The decrease in spectral power was much less pronounced around 10.5 sec ("low frequency"; N.S.) and around 3.6 sec ("high frequency"; N.S.). Evidence is provided here that HRV decreases on magnetically disturbed days, and that it does so in a dose-dependent fashion, HRV being depressed more on days when 20 < Ap < 45 than on days when 7 < Ap < 20, by comparison with days when Ap < 7. This graded response of HRV to geomagnetic activity should encourage us to search for human magnetoreceptors and for a better understanding of putative mechanisms of magnetoreception.

Geomagnetic variations of partly interplanetary origin, with cyclic signatures in human affairs and pathology include the incidence of various diseases, regarding which this study of healthy subjects attempted to determine an underlying mechanism by worldwide archival and physiological monitoring, notably of heart rate variability (HRV). In the past half-century, the possible health and other hazards of natural, solar variability-driven temporal variations in the earth's magnetic field have become a controversial subject in view of the inconsistent results. Some well-documented claims of associations between geomagnetic storms and myocardial infarction or stroke have been rejected by a study based on more comprehensive data analyzed by rigorous methods - covering, however, only part of a solar cycle in only part of a hemisphere. It seems possible that inter-solar cycle and geographic variability, if not geographic differences, may account for discrepancies. Herein, we examine the start of a planetary study on any influence of geomagnetic disturbances that are most pronounced in the auroral oval, on human HRV. The magnetic field variations exhibit complex spectra and include the frequency band between 0.001-10 Hz, which is regarded as ultra-low frequency by physicists. Since the 'ultra-low-frequency' range, like other endpoints used in cardiology, refers to much higher frequencies than the about-yearly changes that are here shown to play a role in environmental-organismic interactions revealed by HRV, the current designations used in cardiology are all placed in quotation marks to indicate the need for possible revision. Whether or not this suggestion has an immediate response, we have pointed to a need for the development of instrumentation and software that renders the assessment of circadian, infradian and even infra-annual (truly low frequency) modulations routinely feasible. HRV was examined on the basis of nearly continuous 7-day records by ECG between December 10, 1998, and November 2, 2000, on 19 clinically healthy subjects, 21 to 54 years of age, in Alta, Norway. A geomagnetic record was obtained from the Auroral Observatory of the University of Tromso. First, frequency-domain measures of HRV were compared for each person in 24-hour spans of high geomagnetic disturbance versus quiet conditions. Second, cross-spectra between geomagnetic activity and HRV measures were quantified via the squared coherence spectrum using 7-day time series. A 7.5% increase in the 24-hour average of heart rate, HR (P = 0.00020) and a decrease in HRV were documented on days of high geomagnetic disturbance. The decrease in HRV was validated statistically for the 'total frequency', 'TF' endpoint (18.6% decrease, P= 0.00009). The decrease in spectral power was found primarily in the 'circaminutan frequency', 'VLF' (21.9% decrease, P< 0.000001) in conjunction with the 'minutes-to-hours' component, ultra-low-frequency, 'ULF' (15.5% decrease, P= 0.00865) and circadecasecundan 'low frequency', 'LF' (14.2% decrease, P = 0.00187) regions of the spectrum. Power-law scaling of the power spectra did not show any statistically significant difference. It is noteworthy that most of the decrease in HRV, except for the circaminutan (VLF) component, was observed only in the season in which sunshine alternated with darkness (D/L), a finding suggesting a mechanism influenced by the alternation of light and darkness. The hypothesis of a light-dark-influenced magnetoreception was also supported by cross-spectral analysis. Group-averaged coherence at frequencies coincident with the geomagnetic Pc 6 pulsations (with periods ranging from 10 minutes to 5 hours) differed with a statistical significance (P < 0.000001) among the three natural lighting conditions, the association being weaker during UL or D/D than during D/L. By contrast, no statistically significant differences were found in terms of the circadian and circasemidian frequencies in relation to the alternation of sunshine with darkness or rather circannual rhythm stage. In conclusion, evidence is provided herein that an alteration of HRV is most apparent in the circaminutan ('VLF') region, which is clinically important, because a reduction in its power is a predictor of morbidity and mortality from cardiovascular disease. The circadecasecundan ('LF') component of HRV also decreased in association with geomagnetic disturbance, which may reflect an episodic alteration of arterial pressure related to changes in geomagnetic activity. Lastly, our study suggests the existence of a light-dark-influenced magnetoreception mechanism in humans involving mainly the Pc 6 band of the magnetic field.