Second Derivative Of Photoplethysmogram Research Articles

Association between blood glucose levels and arterial stiffness marker: comparing the second derivative of photoplethysmogram and cardio-ankle vascular index scores.

This study aimed to compare the association between fasting plasma glucose (FPG) and glycosylated hemoglobin A1c (HbA1c) levels using the second derivative of photoplethysmogram (SDPTG) index and the cardio-ankle vascular index (CAVI). Electronic medical records of 276 participants (160 men, 116 women) who visited the health promotion center of a university hospital were examined. Age, sex, body mass index (BMI), blood pressure, and lipid profile were considered as risk factors for arterial stiffness, together with the FPG, HbA1c, CAVI, and SDPTG indices. Hierarchical regression models were constructed, and all participants were divided into low-normal, high-normal, prediabetic, and diabetic groups to examine the group-based differences in CAVI and SDPTG indices. FPG and HbA1c were independently predictive of increased CAVI, and their predictive powers for CAVI were equivalent (β = 0.214 and 0.200, respectively). Risk factors, including age, BMI, and male sex, were also predictive of CAVI (β= 0.593-0.630, -0.256 - -0.280, and 0.142-0.178, respectively). None of the FPG and HbA1c values were predictive of the SDPTG indices. The CAVI was higher in the diabetes group than in the other three groups according to HbA1c level, while the d/a index of the SDPTG decreased in the prediabetes group and increased in the diabetes group. CAVI may not be substituted for SDPTG indices when evaluating arterial stiffness based on the glucose level. Moreover, the progression rate of arterial stiffness may differ between the diabetic and nondiabetic stages.

Variations in the Second Derivative of a Photoplethysmogram with Age in Healthy Korean Adults.

Second derivative of photoplethysmogram (SDPTG) indices correlate with aging and vascular health. The trend of SDPTG indices with age has not yet been studied in the Korean population. Various SDPTG indices were measured in 300 healthy Koreans (150 men and 150 women), aged 19−69 years, stratified into five age groups consisting of 60 people (30 men and 30 women) in each age group from their 20s to 60s. The values of the SDPTG indices clearly showed distinct variations with age in healthy Korean groups (p < 0.001 for all indices). b/a increased linearly with age (y = 0.0045x − 0.803), as did SDPTG aging index (SDPTG-AI) (y = 0.0162x − 1.1389). c/a decreased linearly with age (y = −0.0044x + 0.1017), as did d/a (y = −0.0062x + 0.034) and e/a (y = −0.001x + 0.2002). A significant sex difference was shown in b/a and e/a ratios and SDPTG-AI (p < 0.001 for all indices); women had a higher b/a ratio (−0.55 ± 0.14 versus −0.65 ± 0.13) and SDPTG-AI (−0.33 ± 0.3 versus −0.52 ± 0.33) and a lower e/a ratio (0.13 ± 0.06 versus 0.18 ± 0.07) than men. A linear regression model of diverse SDPTG indices was provided according to the age of healthy Koreans, which may be valuable in preventing diseases related to vascular conditions by estimating the degradation of arterial function.

Orthostatic response in patients with type 2 diabetes mellitus evaluated through acceleration photoplethysmogram

Introduction: One of the striking complications of diabetes mellitus is arterial circulatory dysfunction. The 30:15 ratio is an orthostatic index commonly used to diagnose circulatory alterations in diabetic patients with a long evolution. Indices obtained from the second derivative of photoplethysmogram (SDPPG) or acceleration photoplethysmogram (APG) characterize arterial pathological changes. Aim: To compare the cardiovascular response of non-diabetic subjects to active standing versus that of type-2 diabetes (DM2) patients using APG indices. Methods: Digital photoplethysmography (PPG) was obtained from healthy subjects (n = 15, age ± SD, 44.6 ± 7.2 years) and DM2 patients (n = 15, age ± SD, 48.3 ± 7.9 years). The 30:15 ratio, b/a, d/a, and APG-AI, all APG-based, of the participants were calculated and compared at baseline, 15 and 30 s. Results: Comparison of the 30:15 ratios between groups did not show a significant difference. No significant differences were observed between the APG indices in the two groups in the baseline period. However, d/a decreased, and APG-AI increased significantly at beat 30 after active standing in non-diabetic subjects. Values of APG indices in DM2 patients did not show significant changes. Conclusion: The results suggest that APG indices could be used to detect early vascular dysfunctions in DM2 patients.

A Study on the Correlation between the Second Derivative of Photoplethysmogram and Quality of Life using SF-36 Questionnaire in Women

A Study on the Correlation between the Second Derivative of Photoplethysmogram and Quality of Life using SF-36 Questionnaire in Women

Is Heart Rate a Confounding Factor for Photoplethysmography Markers? A Systematic Review.

Finger photoplethysmography (PPG) waveform is blood volume change of finger microcirculation that reflects vascular function. Reflection index (RI), stiffness index (SI) and second derivative of photoplethysmogram (SDPPG) are derived from PPG waveforms proposed as cardiovascular disease (CVD) markers. Heart rate (HR) is a known factor that affects vascular function. Individual resting HR variation may affect RI, SI and SDPPG. This review aims to identify studies about the relationship between HR with RI, SI and SDPPG among humans. A literature search was conducted in Medline via the Ebscohost and Scopus databases to find relevant articles published within 11 years. The main inclusion criteria were articles in the English language that discuss the relationship between HR with RI, SI and SDPPG using PPG among humans. The search found 1960 relevant articles but only six articles that met the inclusion criteria. SI and RI showed an association with HR. SDPPG (SDPPG-b/SDPPG-a ratio, SDPPG-d/SDPPG-a ratio, aging index (AGI) and revised aging index (RAGI)) also had an association with HR. Only RI had a considerable association with HR, the association between SI and HR was non-considerable and the association between HR and SDPPG was inconclusive. Further interventional studies should be conducted to investigate this issue, as a variation in resting HR may challenge the validity of PPG-based CVD markers.

Association of the second derivative of photoplethysmogram with age, hemodynamic, autonomic, adiposity, and emotional factors.

The second derivative of photoplethysmogram (SDPTG) is used as an arterial stiffness marker. This study aimed to examine the associations between SDPTG indices and age, in addition to hemodynamic, autonomic, adiposity, and emotional factors.This study had a cross-sectional chart review design, and electronic medical records of 262 women outpatients (mean ± SD,|38.57| ± |11.64 years) were reviewed. Among SDPTG measurements, b/a, c/a, d/a, and (b-c-d)/a were considered. Hemodynamic measurements included systolic and diastolic blood pressure (SBP and DBP) and cardiac output. Autonomic measurements included low and high frequency (LF and HF) values of the heart rate variability. Adiposity measurements included body mass index (BMI) and waist-hip ratio (WHR). Tension, anger, depression, fatigue, confusion, and vigor scores using the Profile of the Mood States were included as emotional markers. All data were normalized through the Box-Cox transformation, and 4 hierarchical regression models were constructed.Age was independently predictive of SDPTG, hemodynamic, autonomic, and adiposity factors (β; 0.143–0.648).After the adjustment for age, SBP and DBP showed negative correlations with d/a (r = –0.201, –0.262), whereas BMI, WHR, LF, and HF showed positive correlations with c/a (r = 0.126, 0.131, 0.151, 0.234). In the hierarchical regression modeling, age and hemodynamic factors were directly predictive of SDPTG indices (β; 0.103–0.626). Age had moderating effects between diastolic blood pressure, heart rate, depression scores, and SDPTG indices (β; 0.104–0.176).In conclusion, age, hemodynamic, adiposity, and autonomic factors may be independently associated with SDPTG indices for women. As age has moderating effects between hemodynamic, emotional factors, and SDPTG indices, its moderating effects should be considered when assessing arterial stiffness using SDPTG indices.

The Examination of the Acute Vascular Changes after Short-Term Smoking Cessation Using Second Derivative of Photoplethysmogram in the Adult Men

The Examination of the Acute Vascular Changes after Short-Term Smoking Cessation Using Second Derivative of Photoplethysmogram in the Adult Men

Usefulness of the second derivative of the finger photoplethysmogram for assessment of end-organ damage: the J-SHIPP study.

Early detection of pathological changes in the vasculature is required to identify individuals at risk of cardiovascular diseases. Noninvasive measurement of the second derivative of photoplethysmogram (SDPTG) might aid in evaluating vascular aging. Here we clarified the diagnostic significance of four SDPTG indices for end-organ damage. A total of 1613 community residents (65±10 years) were enrolled. Changes in blood flow volume at the forefinger were measured by photoplethysmography. SDPTG was computationally calculated from the plethysmogram, and the height of five peaks (a-e) on the SDPTG was measured. Carotid intima-media thickness (IMT), brachial-to-ankle pulse wave velocity (baPWV) and silent cerebral lesions were used as indices of end-organ damage. Multivariate analysis identified age, sex, systolic blood pressure and heart rate as strong determinants for the evaluated SDPTG indices, namely b/a, d/a and aging index ([b-d-c-e]/a). In addition, poor glycemic control and carotid IMT were also weakly associated with the SDPTG indices. Compared with other established risk factors, however, the association between the SDPTG indices and carotid IMT was weak or insignificant (b/a: β=0.069, P=0.002; d/a: β=-0.009, P=0.669; and aging index: β=0.047, P=0.037). Further, no significant association was noted between the SDPTG indices and silent lacunar infarction (b/a: P=0.111; d/a: P=0.263; and aging index: P=0.167) and periventricular hyperintensity (b/a: P=0.587; d/a: P=0.254; and aging index: P=0.429). Although the SDPTG indices evaluated here might represent structural and functional changes in arteries, they exhibited limited diagnostic significance for pathophysiological changes in large arteries, as well as small vessel diseases of the brain.

Framework for Automatic Delineation of Second Derivative of Photoplethysmogram: A Knowledge-based Approach

Knowledge-based rules for delineating the second derivative of photoplethysmogram (SDPTG), which is widely used as an indicator of arterial stiffness, are proposed in this study. The SDPTG facilitates the distinction of five sequential waves, namely the initial positive wave (IPW), the early negative wave (ENW), the late upsloping wave (LUW), the late downsloping wave (LDW), and the diastolic positive wave (DPW). An analysis of these waves indicates that the SDPTG is a slowly time-varying signal and that the difference between two adjacent pulses cannot go beyond a certain range. It also indicates that the diastolic positive wave can be accurately estimated from the envelope of the SDPTG signal even with a noisy signal. To delineate the SDPTG, pulse waveforms are first divided into pulse segments, each of which contains one period of the SDPTG signal, using the slope sum function with an adaptive thresholding scheme, which simplifies detecting pulse onsets by enhancing the upslope of the pulse signal and suppressing the remainder of the signal. After pulse segmentation, IPW is first identified by picking the maximum positive peak in the segment. DPW is then extracted using a knowledge-based rule that uses the envelope of the SDPTG signal. In the range from IPW to DPW, ENW, LUW, and LDW are sequentially determined using knowledgebased rules. The proposed method is evaluated using the HIMS database, which includes 1,386 pulses. A positive predictive value of 99.71% and a false negative rate of 1.02% are obtained, and thus the proposed rules are expected to facilitate pulse diagnosis using SDPTG signals.

Study of cardiovascular effects of caffeine in healthy human subjects, with special reference to pulse wave velocity using photoplethysmography

Introduction: Caffeine is one of the most widely used pharmacologically active substances. It increases blood pressure and peripheral vascular resistance by stimulation of the sympathetic nervous system. Studies on the cardiovascular effects of caffeine have often produced contradictory results. Arterial stiffness and pulse wave reflections are important determinants of the efficient performance of the cardiovascular system, with prognostic value for cardiovascular risk. Materials and Methods: This is a randomized, double-blind, placebo-controlled, parallel-design study, comparing the effects of a single oral dose of 250 mg or 500 mg caffeine and placebo on arterial stiffness and pulse wave reflections in 36 healthy male subjects by measuring arterial pulse wave velocity by recording fingertip second derivative of photoplethysmogram (SDPTG) and ECG simultaneously. Blood pressure, heart rate, pulse wave velocity, and b/a ratio (SDPTG index) were measured at baseline and at 30 and 60 minutes after administration of caffeine. Results: Compared to baseline, systolic and diastolic blood pressures were increased significantly at 30 minutes and 60 minutes with caffeine, while heart rate decreased significantly at 30 minutes (P<0.05 for 250mg and P<0.01 for 500mg caffeine) but showed no significant change at 60 minutes. Pulse wave velocity increased significantly with both the doses of caffeine at 30 minutes (P<0.05) and 60 minutes (P<0.001). Similarly, the b/a ratio also increased significantly at 30 minutes (P<0.01) and 60 minutes (P<0.01) with 250 mg, but the change was insignificant with 500 mg. No significant changes were observed after administration of placebo. Conclusion: Acute administration of caffeine produced rise in blood pressure, arterial stiffness, and change in wave reflections in healthy subjects as indicated by pulse wave velocity and b/a ratio.

Characteristic alteration in the second derivative of photoplethysmogram in children

The second derivative of the photoplethysmogram (SDPTG) has been verified as a useful method for analyzing pulse wave form in adults; however, there have been few studies on the SDPTG in children. We examined age-related alteration of SDPTG (study 1) and the SDPTG response to a vasodilator (study 2). The subjects in study 1 were 36 healthy children aged 0.9-16.0 years. The subjects in study 2 were 13 children aged 5.4-18.9 years with a history of Kawasaki disease. Subjects received an i.v. infusion of 0.568 mg/kg dipyridamole. We assessed the SDPTG by d/a ratio, b/a ratio and aging index (AGI). The d/a ratio increased with advance of age (r= 0.636, P < 0.001), and the b/a ratio and AGI decreased with advance of age (r=-0.343, P < 0.05 and r=-0.678, P < 0.001, respectively). The d/a ratio and AGI were correlated with height (r= 0.523, P < 0.01 and r=-0.623, P < 0.001, respectively), but the b/a ratio was not significantly correlated with height. In study 2, the d/a ratio increased significantly (P≤ 0.05), but the b/a ratio and AGI did not alter. The SDPTG indices in children show characteristic alterations with advance of age and react to a vasodilator.

Effects of Parametric Speaker Sound on Physiological Functions during Mental Task

In recent years, parametric speakers have been used in various circumstances. However, nothing has yet been demonstrated about the safety of parametric speakers for the human body. Therefore, we studied their effects on physiological functions. Nine male subjects participated in this study. They completed three consecutive sessions: a 20-min quiet period as a baseline, a 45-min mental task period with a general speaker or a parametric speaker, and a 20-min recovery period. We measured electrocardiogram (ECG), photoplethysmogram (PTG), electroencephalogram (EEG), blood pressure (BP), and baroreflex sensitivity (BRS). Two experiments, one with a general speaker (the general condition), the other with a parametric speaker (the parametric condition), were conducted at the same time of day on separate days. To examine the effects of the parametric speaker, a two-way repeated measures ANOVA (speaker factor and time factor) was conducted. We found that sympathetic nervous activity and second derivative of PTG in task period and recovery period during the parametric condition were significantly lower than those indications during the general condition. Furthermore, Δ parasympathetic nervous activity during the parametric condition in task period and recovery period tended to be smaller than that during the general condition. The results suggested that the burden of the parametric speaker is lower than that of the general speaker for physiological functions, especially those of the cardiovascular system. Furthermore, we verified that the reaction time with the parametric speaker is shorter than that with the general speaker.

The Examination of the Acute Vascular Changes Due to Smoking Using Second Derivative of Photoplethysmogram

Background: Although smoking is the major risk factor for atherosclerosis under the age of 40, the smoking rate of adolescent and young adult has been is increasing. In case of young adults, there is no available clinical indices reflecting harmful effects of smoking. The aim of this study was to investigate whether any second derivative of photoplethysmogram (SDPTG) index can be used as a clinical index of acute effects of smoking. Methods: Twenty smoking and eighteen never-smoking males ages between 20-39 without medical history of atherosclerotic disease nor peripheral vascular diseases were selected for this study. We investigated the life styles and risk factors of atherosclerosis through a questionnaire, laboratory test and physical examination. We measured SDPTG at baseline, 3, 5, 10, 15, and 20 minutes for smokers after smoking and walking and for never-smokers after walking. Repeated measures ANOVA and ANCOVA were used for analysing the changes of SDPTG according to time. Results: The heart rate and blood vessel tension (BVT) were different between the smokers and never-smokers after adjusting age, fasting blood sugar, body mass index, depression, and exercise (P < 0.05, P < 0.05, respectively). In contrast to never-smokers, heart rate of smokers at 3 minutes after smoking was increased for 10.1 per minute (P < 0.001) and higher than never-smokers until 15 minutes (P < 0.05). BVT in smokers was decreased at 3 minutes (P < 0.05) from baseline and lower than never-smokers at 3 minutes (P < 0.05). Differential pulse wave index, stress power, remained blood volume, and the changes of these indices according to time were not significantly different between the two groups. Conclusion: BVT and heart rate reflected the acute effect of smoking on blood vessels and could be used to provide motivation to quit smoking and make people more concerned about their own health especially to the young smokers who has no symptoms yet.

Effects of safflower seed extract on arterial stiffness

Safflower seed extract (SSE) contains characteristic polyphenols and serotonin derivatives (N-( p-coumaroyl) serotonin and N-feruloylserotonin), which are reported to inhibit oxidation of low-density lipoprotein (LDL), formation of atherosclerotic plaques, and improve arterial stiffness as assessed by pulse wave analysis in animal models. The effects of long-term supplementation with SSE on arterial stiffness in human subjects were evaluated. This doubleblind, placebo-controlled study was conducted in 77 males (35–65 years) and 15 postmenopausal females (55–65 years) with high-normal blood pressure or mild hypertension who were not undergoing treatment. Subjects received SSE (70 mg/day as serotonin derivatives) or placebo for 12 weeks, and pulse wave measurements, ie, second derivative of photoplethysmogram (SDPTG), augmentation index, and brachial-ankle pulse wave velocity (baPWV) were conducted at baseline, and at weeks 4, 8, and 12. Vascular age estimated by SDPTG aging index improved in the SSE-supplemented group when compared with the placebo group at four (P = 0.0368) and 12 weeks (P = 0.0927). The trend of augmentation index reduction (P = 0.072 versus baseline) was observed in the SSE-supplemented group, but reduction of baPWV by SSE supplementation was not observed. The SSE-supplemented group also showed a trend towards a lower malondialdehyde-modified-LDL autoantibody titer at 12 weeks from baseline. These results suggest long-term ingestion of SSE in humans could help to improve arterial stiffness.

Post-challenge hyperglycaemia is an independent risk factor for arterial stiffness in Japanese men.

Arterial stiffness is an independent predictor of cardiovascular disease, but the impact of post-challenge hyperglycaemia on arterial stiffness is unknown. To investigate the association between arterial stiffness and post-challenge hyperglycaemia, we measured the second derivative of photoplethysmogram as an indicator of arterial stiffness. This study was done in 159 asymptomatic Japanese men aged 50.7 +/- 13.0 years. All subjects underwent a 75-g oral glucose tolerance test and measurement of the second derivative of photoplethysmogram. According to the World Health Organization criteria (1998), 110 subjects had normal glucose tolerance, 10 had impaired fasting glucose, 30 had impaired glucose tolerance, and nine had diabetes. The b/a ratio (an index of arterial stiffness) showed a significant relationship with age (r = 0.58, P < 0.0001), height (r = -0.33, P < 0.0001), 2-h post-challenge glucose (r = 0.32, P < 0.0001), systolic blood pressure (r = 0.22, P = 0.006), and diastolic blood pressure (r = 0.21, P = 0.009). After adjustment for age and height, there were significant correlations between the b/a ratio and diastolic blood pressure (r = 0.18, P = 0.02), fasting glucose (r = 0.16, P = 0.049), and 2-h post-challenge glucose (r = 0.21, P = 0.009). Stepwise multiple regression analysis showed that only age (beta= 0.006, SE = 0.0007, P < 0.001) and 2-h post-challenge glucose (beta = 0.0005, SE = 0.0002, P < 0.05) contributed significantly to the b/a ratio (adjusted R(2) = 0.38). These results indicate that post-challenge hyperglycaemia is an independent risk factor for arterial stiffness.

Arterial stiffness index: A new evaluation for arterial stiffness in elderly patients with essential hypertension

Background: Arterial stiffness is one of the predictors of cardiovascular event. Arterial stiffness is commonly measured by pulse wave velocity between the carotid and femoral arteries. Recently the arterial stiffness index which is measured by computerized oscillometry at the upper arm was developed. As this procedure is a convenient means of measuring pulse wave velocity, we considered it suitable to evaluate arterial stiffness in elderly patients. We evaluated this arterial stiffness index and compared it with other methods of evaluating arterial stiffness in hypertensive patients, including the elderly.Methods: Forty‐two patients with essential hypertension, including 26 subjects over 60 years old were enrolled. We evaluated the arterial stiffness index by computerized oscillometry, and also evaluated arterial stiffness between the carotid‐femoral artery and the brachial‐tibial artery, the second derivative of photoplethysmogram, the forearm vasodilator response to reactive hyperemia by strain‐gauge plethysmography.Results: Arterial stiffness index was positively correlated with pulse wave velocity between the carotid‐femoral artery (P &lt; 0.0001; r = 0.579), the heart‐carotid artery (r = 0.454) and right brachial‐tibial artery (r = 0.549). It was also correlated with b/a (r = 0.474) and d/a (r = 0.568) by a second derivative of photoplethysmogram, but not correlated with a reactive vasodilator response. In elderly patients, arterial stiffness index was also correlated with carotid‐femoral pulse wave velocity (P &lt; 0.05; r = 0.456) but not correlated with a vasodilator response to reactive hyperemia.Conclusion: These data suggest that arterial stiffness index is correlated to common pulse wave velocity between the carotid and femoral arteries, so this index might be useful to evaluate arterial stiffness in hypertensive patients including the elderly.

Assessment of vascular aging and atherosclerosis in hypertensive subjects: second derivative of photoplethysmogram versus pulse wave velocity

The pulse wave velocity (PWV) and the photoplethysmogram (PTG) are noninvasive methods for evaluating the pulse wave. The PWV has been associated with age and arterial hypertension, and an index of the second derivative of PTG (SDPTG) is correlated with age and other risk factors for atherosclerosis. The aim of this study was to compare SDPTG and PWV concerning the influencing factors of vascular compliance, including age and atherosclerosis, in a large hypertensive population. We studied consecutively 524 essential hypertensives, 140 with atherosclerotic alterations (AA), defined on the basis of clinical events including coronary heart disease, peripheral vascular disease, stroke, and abdominal aorta aneurysm. The PWV carotid-femoral was measured by a Complior device and the SDPTG was recorded by Fukuda FCP-3166. The augmentation index (AUI) of PTG was defined as the ratio of the late systolic peak to that of the early systolic peak in the pulse. The SDPTG consists of an a,b,c, and d wave in systole and an e wave in diastole; an SDPTG aging index (AI) was calculated as (b-c-d-e)/a. The patients with AA presented a higher PWV (14.9 ± 4 m/sec v 12.4 ± 2 m/sec, P < .001), PTG AUI (0.322 ± 0.16 v 0.252 ± 0.09, P < .001), and SDPTG AI (−0.093 ± 0.03 v −0.271 ± 0.018, P < .001). However, in patients <60 years of age, only PWV remained higher in those with AA, whereas in patients >60 yr, both PWV and SDPTG AI remained higher in those with AA. The PWV was independently influenced by age, systolic blood pressure, glucose, AA, and plasma creatinine, whereas the PTG AUI was influenced by age and systolic pressure and the SDPTG AI by age and AA. In a logistic regression model for the presence of AA, including age, plasma creatinine, smoking, and diastolic BP, PWV was a significant independent determinant of AA, whereas SDPTG-AI weakly entered into the model. This study provides evidence that the aortic PWV reflects better than the SDPTG the modifications of the arterial compliance related to age, blood pressure, and atherosclerosis. However, the SDPTG AI may be useful for evaluation of vascular aging in hypertensives.

加速度脈波による血管年齢の推定

加速度脈波による血管年齢の推定