Acceleration Index Research Articles

Comparative analysis of ride comfort evaluation indices of high-speed vehicles based on a vehicle-seat-human body coupled dynamics model

As high-speed vehicles become increasingly lightweight, the influence of passengers on the vehicle vibration system cannot be overlooked. In this paper, a 3D vehicle-seat-human body coupled dynamics model is established to comprehensively evaluate the ride comfort of high-speed vehicles. The model combines the passenger biomechanics with the carbody flexibility. This is often neglected in previous studies and only the carbody vibrations are considered. Applying the validated model, four types of ride comfort evaluation indices are calculated and compared at 250–400 km/h. Results show that the ride comfort of high-speed vehicles at different speeds is excellent when the carbody acceleration and Sperling indices are used. While the results are significantly different when the total equivalent weighted acceleration and annoyance rate indices based on human body vibrations are used. At full load and speed of 400 km/h, the passengers sitting near the windows at both ends of the carbody felt ‘slightly uncomfortable’ or ‘less comfortable’ with an annoyance rate of about 30%, which indicates that up to 30% of the passengers might find the vibrations intolerable. This study underscores the necessity of integrating human body vibrations and passenger subjective psychology into ride comfort assessments, which can provide theory references for the selection and optimization of evaluation indices for high-speed lightweight vehicles.

Enhanced Transformer Overcurrent Protection via Oil Temperature Acceleration

When a transformer is in a long-term heavy load operation state, the oil temperature reaches the alarm temperature; if a slight fault occurs inside the transformer, traditional inverse time current protection and other protections that react to phase current may not operate due to insufficient sensitivity or they may operate for too long. Based on this, this article proposes a new principle of accelerating inverse time overcurrent protection based on transformer oil temperature. The proposed method uses transformer oil temperature to accelerate the action time of traditional inverse-time overcurrent protection, then introduces the transformer oil temperature factor and acceleration index to optimize the inverse time characteristic curve, and establishes a mathematical model to optimize the adjustment for the complexity of adjustment of the protection action equation and the risk of mismatch of the protection after the acceleration of oil temperature. The existing theoretical analysis and simulation verification results show that the proposed new overcurrent protection scheme based on the transformer oil temperature acceleration inverse time can effectively improve the protection of the rapidity and sensitivity, providing a new research idea for the combination of non-electrical and electrical quantity protection.

Acromegaly: The Relationship between Hemodynamic Profiles Assessed via Impedance Cardiography and Left Ventricular Systolic Function Assessed via Echocardiography.

Background/Objectives: Acromegaly-induced prolonged exposure to growth hormone and insulin-like growth factor 1 may have significant cardiovascular effects. The purpose of this study was to assess the relationship between hemodynamic parameters measured via impedance cardiography (ICG) and parameters of systolic left ventricular function measured via echocardiography in patients with acromegaly. Methods: The observational cohort study included 33 patients with newly diagnosed acromegaly, with a mean age of 47 years and without significant comorbidities. Correlation analysis (Spearman's rank correlation coefficient R) was performed on parameters obtained by ICG and left ventricular systolic function parameters obtained by echocardiography. ICG assessment included indices of (1) cardiac function as a pump: stroke volume index (SI), cardiac index (CI), Heather index (HI), velocity index (VI), and acceleration index (ACI); (2) afterload: systemic vascular resistance index (SVRI) and total arterial compliance index (TACI); and (3) thoracic fluid content (TFC). Echocardiographic examinations evaluated left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). Results: A lower LVEF was associated with a lower SI (R = 0.38; p = 0.03) and a higher SVRI (R = -0.35; p = 0.046), whereas lower GLS was associated with lower SI (R = 0.43; p = 0.02), CI (R = 0.62; p < 0.001), VI (R = 0.59; p < 0.001), ACI (R = 0.38; p = 0.048), HI (R = 0.59; p < 0.001), and TACI (R = 0.50; p = 0.006) and a higher SVRI (R = -0.59; p < 0.001). No significant correlation was observed between either LVEF or GLS and TFC. Conclusions: In patients with acromegaly, poorer echocardiographic parameters of left ventricular systolic function are associated with impaired function of the heart as a pump and higher afterload as assessed via ICG.

Acceleration index predicts efficacy of orthostatic training on postural orthostatic tachycardia syndrome in children.

Electrocardiographic acceleration index can be used to predict the effectiveness of orthostatic training in treating children with POTS. • Postural orthostatic tachycardia syndrome (POTS) is a chronic orthostatic intolerance involving multiple mechanisms. Autonomic dysfunction is one of the main mechanisms of POTS in children and could be treated with orthostatic training. • In order to improve the efficacy of orthostatic training in children with POTS, it is particularly important to identify the patients with autonomic dysfunction as the main mechanism before the treatment. • We found acceleration index of the electrocardiogram (ECG) can be used as a satisfactory index to predict the efficacy of orthostatic training in the treatment of POTS in children. • Using the acceleration index to predict the efficacy of orthostatic training on POTS in children is easy to be popularized in hospitals at all levels because it is non-invasive, convenient, and not expensive.

The Diagnostic Accuracy of Sonographic Parameters for Renal Artery Stenosis in Adults: A Rapid Literature Review Based on a Statistical Approach

Objective: The aim of this study was to determine the 95% confidence interval (CI) cutoff for sonographic renal artery stenosis (RAS) parameters. A secondary objective was to determine the diagnostic accuracy parameters of peak systolic velocity (PSV), renal aortic ratio (RAR), acceleration index (AI), and acceleration time (AT) for diagnosing RAS. Materials and Methods: Diagnostic test accuracy (DTA) parameters and 95% CIs were evaluated for the sonographic cutoff values. A total of 31 articles were extracted and subjected to statistical analysis. Results: The mean 95% CI cutoff for PSV, RAR, AI, and AT were 192.50 (175.16, 209.84), 3.10 (2.83, 3.38), 3.39 (2.51, 4.27), and 80.78 (68.56, 93.01), respectively. The pooled mean 95% CI sensitivity of PSV, RAR, AI, and AT were 85.90% (79.84, 91.97), 82.34% (77.58, 87.11), 74.92% (64.53, 85.33), and 73.57% (63.01, 84.13), respectively, whereas the pooled mean specificity of the same parameters was 82.52% (75.78, 89.25), 86.97% (83.12, 90.82), 78.93% (66.34, 91.52), and 82.57% (70.70, 94.44), respectively. Conclusion: The pooled mean 95% CI for sensitivity and specificity of the sonographic parameters was concordant with the literature. Based on this higher level of evidence, except RAR, the mean 95% CI cutoff for PSV, AI, and AT were consistent with the cutoff values encountered in the published literature.

Correlating ballast resilient modulus with particle movement through SmartRock sensing

The resilient modulus of ballast is a key parameter in assessing track quality and is influenced by various loading conditions, such as deviator stress, bulk stress, loading frequency, and confining pressure. These factors, when incorporated into different models, can sometimes complicate their application in track maintenance planning. Therefore, a simplified model that collectively considers these factors would be beneficial in practical applications for estimating the ballast resilient modulus. This study utilizes smart sensing technology, SmartRock, to track particle movement during large-scale triaxial cyclic loading tests, exploring the potential correlation between ballast resilient modulus and particle motion. The findings indicate that the settling acceleration of ballast particles significantly impacts the ballast resilient modulus. This effect is dependent on the applied cyclic loading pulses, an aspect previously overlooked in research. Consequently, an index termed the Cyclic Loading and Acceleration Index (CLAI) has been introduced. CLAI integrates the effects of deviator stress, loading frequency, loading pulses, and settling acceleration. Based on CLAI, a simplified model for ballast resilient modulus has been developed and validated.

Predicting the cognitive impairment with multimodal ophthalmic imaging and artificial neural network for community screening

Background/aimsTo investigate the comprehensive prediction ability for cognitive impairment in a general elder population using the combination of the multimodal ophthalmic imaging and artificial neural networks.MethodsPatients with cognitive impairment and...

AORTIC STENOSIS AND ULTRASOUND EVALUATION OF RENAL VESSELS IN HYPERTENSIVE PATIENTS

Objective: Aortic stenosis (AS) and arterial hypertension often clusterize and increase cardiovascular disease burden. Renal artery (RA) stenosis, the main form of secondary hypertension, can act as an upstream factor of resistance at the same way of AS. Aim of the study: to investigate if the presence of AS is able to interfere with the ultrasound (US) parameters in the diagnosis of RA stenosis. Design and method: In hypertensive subjects with AS we evaluated US indirect parenchymal parameters: resistive index (RI) and index of maximal systolic acceleration (AImax: the maximal acceleration of flow waveform in early systole divided by the peak systolic velocity), and US direct RA parameters: peak systolic velocity (PSV) and Renal/Aortic Ratio (RAR). Results: We compared hypertensive patients (mean age 74 years) with preserved left ventricular function with severe AS (n=18) or mild AS (n=21). No statistically differences were detected between groups regarding gender, age, smoke, ABI, CV risk factors, lipids, and renal function. Direct US parameters of RA did not differ significantly between patients with severe or mild AS (mean PSV 113 vs 127 cm/sec; mean RAR 1.3 vs 1.6). RI showed the same behavior (0.75 vs 0.73). AImax was significantly lower in patients with severe vs mild AS (8.74 vs 15.56 1/sec, p&lt;0.0005). We found an inverse correlation between AImax and the mean (r2=0.435) and peak (r2=0.424) transvalvular gradient. Among 14 patients with severe AS underwent correction of valvular disease. At 6 months, US showed a significant increase in AImax (from 10.0 to 19.8 1/sec, p&lt;0.005), while RI did not differ significantly (0.74 vs 0.73). Conclusions: Severe AS act as a proximal resistance that can attenuate the systolic acceleration phase of the flow profile of the renal intraparenchymal vessels, in particular of AImax, which is restored after surgical correction of the valve defect. Presence of AS may affect the diagnostic workup of RA stenosis.

Effects of the Flying Start on Estimated Short Sprint Profiles Using Timing Gates.

Short sprints are predominantly assessed using timing gates and analyzed through parameters of the mono-exponential equation, including estimated maximal sprinting speed (MSS) and relative acceleration (TAU), derived maximum acceleration (MAC), and relative propulsive maximal power (PMAX), further referred to as the No Correction model. However, the frequently recommended flying start technique introduces a bias during parameter estimation. To correct this, two additional models (Estimated TC and Estimated FD) were proposed. To estimate model precision and sensitivity to detect the change, 31 basketball players executed multiple 30 m sprints. Athlete performance was simultaneously measured by a laser gun and timing gates positioned at 5, 10, 20, and 30 m. Short sprint parameters were estimated using a laser gun, representing the criterion measure, and five different timing gate models, representing the practical measures. Only the MSS parameter demonstrated a high agreement between the laser gun and timing gate models, using the percent mean absolute difference (%MAD) estimator (%MAD < 10%). The MSS parameter also showed the highest sensitivity, using the minimum detectable change estimator (%MDC95), with an estimated %MDC95 < 17%. Interestingly, sensitivity was the highest for the No Correction model (%MDC95 < 7%). All other parameters and models demonstrated an unsatisfying level of sensitivity. Thus, sports practitioners should be cautious when using timing gates to estimate maximum acceleration indices and changes in their respective levels.

Accelerometer-based gait characteristics and their discrimination of gait independence in inpatients with subacute stroke

BackgroundGait analysis using inertial measurement devices can identify multifaceted gait disorders after a stroke. Although the usefulness of gait assessment using inertial measurement devices has been reported, its accuracy in discriminating gait independence in patients hospitalized for subacute stroke has not yet been validated. Research questionCan trunk acceleration indices discriminate between dependent and independent walking in patients with subacute stroke? MethodsThirty-five patients with subacute stroke (mean ± standard deviation, 75.5 ± 9.8 years, 19 males), who were able to understand instructions, had a premorbid modified Rankin scale <3, and were able to walk 16 m straight ahead under supervision were included. The stride regularity, harmonic ratio, and normalized root mean square of trunk accelerations were measured in three directions (mediolateral, vertical, and anterioposterior) during comfortable walking. The Functional Ambulation Categories were used as the dependent variable to classify the patients into two groups (dependent and independent walking groups), and each trunk acceleration index was used as the independent variable to calculate the area under the curve using receiver operating characteristic curves. ResultsTwelve patients were in the dependent group and 23 were in the independent group. The normalized root mean square in both the mediolateral and vertical directions were excellent discriminators of walking independence, with an area under the curve greater than 0.8. The cutoff values (sensitivity/specificity) were 2.20 m2/s2 (0.783/0.833) and 2.82 m2/s2 (0.739/0.833), respectively. SignificanceThe magnitude of vertical and lateral acceleration during gait in patients with subacute stroke, has excellent accuracy in discriminating between dependent and independent gaits. The results of this study will be useful for inexperienced clinicians working with stroke patients presenting with gait disturbances to accurately determine gait independence based on objective data.

Obesity-Related Hemodynamic Alterations in Patients with Cushing's Disease.

Background: Cushing's disease (CD) is associated with a specific form of metabolic syndrome that includes visceral obesity, which may affect cardiovascular hemodynamics by stimulating hypercortisolism-related metabolic activity. The purpose of this study was to evaluate the relationship between obesity and the hemodynamic profile of patients with CD. Methods: This prospective clinical study involved a hemodynamic status assessment of 54 patients newly diagnosed with CD with no significant comorbidities (mean age of 41 years). The assessments included impedance cardiography (ICG) to assess such parameters as stroke index (SI), cardiac index (CI), velocity index (VI), acceleration index (ACI), Heather index (HI), systemic vascular resistance index (SVRI), and total arterial compliance index (TACI) as well as applanation tonometry to assess such parameters as central pulse pressure (CPP) and augmentation index (AI). These assessments were complemented by echocardiography to assess cardiac structure and function. Results: Compared with CD patients without obesity, individuals with CD and obesity (defined as a body mass index ≥ 30 kg/m2) exhibited significantly lower values of ICG parameters characterizing the pumping function of the heart (VI: 37.0 ± 9.5 vs. 47.2 ± 14.3 × 1*1000-1*s-1, p = 0.006; ACI: 58.7 ± 23.5 vs. 76.0 ± 23.5 × 1/100/s2, p = 0.005; HI: 11.1 ± 3.5 vs. 14.6 ± 5.5 × Ohm/s2, p = 0.01), whereas echocardiography in obese patients showed larger heart chamber sizes and a higher left ventricular mass index. No significant intergroup differences in blood pressure, heart rate, LVEF, GLS, TACI, CPP, or AI were noted. Conclusions: Hemodynamic changes associated with obesity already occur at an early stage of CD and manifest via significantly lower values of the ICG parameters illustrating the heart's function as a pump, despite the normal function of the left ventricle in echocardiography.

Study on dynamic performance of high-speed railway vehicle using roller rig and numerical simulation

The development of high-speed trains has increased the demand for dynamic vehicle tests on roller rigs. This study presents a nonlinear multi-body dynamic model of a vehicle system running on a roller rig and an actual track. Dynamic tests for a high-speed vehicle were performed using a full-scale roller rig to validate the numerical model. The hunting stability characteristics of the vehicle were investigated by performing a comparative analysis of the roller rig tests and numerical simulations of the vehicle on roller rigs and tracks. The results indicate that the critical hunting speed of the vehicle on a roller rig is lower than that on a track, particularly under significantly high or low equivalent conicity and yaw damper failure conditions. The characteristics of the hunting stability, riding performance, and lateral acceleration of the bogie frame were comparable in both rig tests and line operations, exhibiting consistent trends under the normal operation of the suspension system with the wheel/rail matches existing within the ideal range of equivalent conicity. However, the lateral acceleration or lateral Sperling index of the carbody could better detect the carbody hunting under low equivalent conicities, particularly when the lateral acceleration of the bogie was not sufficiently effective.

Liquefaction potential analysis based on standard penetration test in coastal area (Case study: Loh Buaya, Rinca Island, Indonesia)

An area has liquefaction potential when it has a shallow groundwater level, loose sandy soil, and is prone to earthquakes. There are several areas with such criteria that have not been analysed for liquefaction potential. This study aims to analyse and plot the liquefaction potential in the coastal area of Loh Buaya, Rinca Island, East Nusa Tenggara Province. Soil investigation data, such as SPT, sieve analysis, and groundwater level, as well as earthquake history that occurred from 1922-2022, served as the main data for liquefaction potential analyses. The methods used were Ground Motion Equation Prediction (GMPE) to calculate Peak Ground Acceleration (PGA), Simplified Procedure, and Liquefaction Severity Index (LSI) to make a liquefaction hazard assessment. LSI scores were used to provide micro-zonation of liquefaction potential with Inverse Distance Weighted (IDW) interpolation in QGIS. The result obtained is very dense gravel has no liquefaction potential whereas loose sandy soil has very high in LSI classification because loose sandy soil has liquefaction potential up to 20 meters of depth. The applying of micro-zonation LSI by IDW interpolation method can estimate the potential level of liquefaction hazard on Loh Buaya, Rinca Island with limited soil investigation data.

Estimating weakening on hillslopes caused by strong earthquakes

The weakening of hillslopes during strong earthquakes increases landsliding rates in post-seismic periods. However, very few studies have addressed the amount of coseismic reduction in shear strength of hillslope materials. This makes estimation of post-seismic landslide susceptibility challenging. Here we propose a method to quantify the maximum shear-strength reduction expected on seismically disturbed hillslopes. We focus on a subset of the area affected by the 2008 Mw 7.9 Wenchuan, China earthquake. We combine physical and data-driven modeling approaches. First, we back-analyze shear-strength reduction at locations where post-seismic landslides occurred. Second, we regress the estimated shear-strength reduction against peak ground acceleration, local relief, and topographic position index to extrapolate the shear-strength reduction over the entire study area. Our results show a maximum of 60%–75% reduction in near-surface shear strength over a peak ground acceleration range of 0.5–0.9 g. Reduction percentages can be generalized using a data-driven model.

RADIATION-STIMULATED DIFFUSION IN PLASMA-ION DEPOSITION OF COATINGS

The diffusion of defects in a carbon coating when its surface is bombarded with heavy low-energy ions is theoretically studied, taking into account a sharp increase in the rate of kinetic processes in nonlocal thermoelastic peaks (NTPs) of ions, i.e., in superheated nanometer regions that arise around ion trajectories in the target material. The thermal energy density in NTP is comparable to or exceeds the activation energies of many physical and chemical processes, as a result of which their contribution to the total diffusion of defects in the near-surface layer of the target can be significant. Based on the NTP model, expressions were obtained for the average diffusion coefficient in the near-surface layer of the target, controlled by a beam of incident ions, as well as for the diffusion acceleration index. The dependences of the diffusion acceleration index on the ion energy are presented for various species of ions at selected activation energies and ion flux densities. Numerical calculation of the obtained expressions using the SRIM2000 software package showed that, at the selected ion flux density J, diffusion acceleration occurs only for processes with the activation energy exceeding a certain threshold value determined by the value of J, the type and energy of the ions.

The Heart's Function as a Pump Assessed via Impedance Cardiography and the Autonomic System Balance in Patients with Early-Stage Acromegaly.

Acromegaly is a rare, chronic disease that involves structural and functional abnormalities of the cardiovascular system. Acromegaly likely affects interactions between the cardiovascular system and the autonomic nervous system (ANS). Therefore, assessing the relationship between sympathetic-parasympathetic balance by analyzing heart rate variability (HRV) and the hemodynamic profile via impedance cardiography (ICG) may be useful in learning the exact nature of interactions between the ANS and the cardiovascular system. The purpose of this study was to assess a possible association between HRV and ICG-based parameters of cardiac function in patients newly diagnosed with acromegaly. This observational cohort study was conducted on 33 patients (18 men, mean age of 47 years) newly diagnosed with acromegaly and no significant comorbidities. A correlation analysis (Spearman's rank coefficient R) of the parameters assessed via ICG and the HRV assessed via 24 h ambulatory electrocardiography was performed. ICG assessments included the following parameters: stroke volume index (SI), cardiac index (CI), acceleration index (ACI), velocity index (VI), and Heather index (HI). The analysis of HRV included both time-domain parameters (pNN50, SDNN, SDSD, rMSSD) and frequency-domain parameters (total power (TP) and its individual frequency bands: low-frequency (LF day/night), high-frequency (HF day/night), and the LF/HF ratio (day/night)). Frequency-domain HRV analysis showed the following correlations: (1) lower nighttime LF values with higher ACI (R = -0.38; p = 0.027) and HI (R = -0.46; p = 0.007) values; (2) higher nighttime HF values with higher ACI (R = 0.39; p = 0.027) and HI (R = 0.43; p = 0.014) values; (3) lower nighttime LF/HF values with higher ACI (R = -0.36; p = 0.037) and HI (R = -0.42; p = 0.014) values; (4) higher nighttime TP values with higher SI values (R = 0.35; p = 0.049). Time-domain parameters of HRV showed a significant correlation only between the nighttime values of SDSD and SI (R = 0.35; p = 0.049) and between the daytime and nighttime values of SDNN and HR (R = -0.50; p = 0.003 and R = -0.35; p = 0.046). In multivariate regression, only ACI was revealed to be independently related to HRV. In patients newly diagnosed with acromegaly, the relationship between the sympathetic-parasympathetic balance assessed via HRV and the hemodynamic profile assessed via ICG was revealed. Better function of the left ventricle was associated with a parasympathetic shift in the autonomic balance.

The effect of using walking poles on the spatiotemporal gait parameters in patients who underwent surgery for hip fractures

Purpose This study aimed to investigate the differences in spatiotemporal gait parameters in patients who underwent surgery for hip fractures when using walking poles and T-canes. Methods This cross-sectional study enrolled eight patients who underwent surgery for a unilateral hip fracture (mean age, 79.0 ± 7.9 years) and 34 healthy individuals who had no symptoms (mean age, 32.1 ± 6.2 years). The outcome measures were the walking speed, trunk acceleration, and lateral lean angles of the trunk, shoulder, and pelvis during walking. The results were compared among the three types of walking aids, namely, a T-cane, double T-canes, and walking poles. Results Acceleration indices step symmetry in the vertical and anteroposterior directions in walking with walking poles were significantly larger than that in walking with a T-cane. These results were common in patients with fractures and healthy individuals. Conclusions Walking with walking poles might be a more symmetrical gait style than walking with a T-cane in patients who underwent surgery for hip fractures.

Comparisons of choroidal blood flow velocity between initial-onset acute uveitis associated with Vogt-Koyanagi-Harada disease and acute central serous chorioretinopathy.

Acute central serous chorioretinopathy (CSC) and Vogt-Koyanagi-Harada (VKH) disease in the acute uveitic phase are characterized by serous retinal detachment caused by dysfunction of the choroid. The aim of this study is to compare blood flow velocity and pulse waveform parameters in the choroid between these two diseases. In this study, 25 patients (50 eyes) with VKH disease, 21 patients (27 eyes) with CSC and 15 healthy controls (30 eyes) were studied. Laser speckle flowgraphy (LSFG) was performed at presentation. Choroidal mean blur rate (MBR), representing blood flow velocity in choroidal vessels, was significantly lower in the eyes affected by VKH disease compared with the healthy control and CSC eyes. CSC eyes had a significantly higher MBR compared with healthy controls. Among the analyzed pulse waveform parameters, blow-out time (BOT), falling rate (FR) and flow acceleration index (FAI) changed significantly. BOT value was significantly lower in CSC eyes than in healthy control and VKH eyes. FR and FAI values were significantly lower in VKH eyes than in healthy control and CSC eyes. There was a strong positive correlation between MBR and FAI. Our findings confirm different pathophysiology of these two diseases. Assessment of choroidal blood flow velocity and haemodynamics with LSFG provides useful information to differentiate acute CSC and initial-onset acute uveitis associated with VKH disease.

Impedance cardiogram based exploration of cardiac mechanisms in post-traumatic stress disorder during trauma recall.

Post-traumatic stress disorder (PTSD) is an independent risk factor for developing heart failure; however, the underlying cardiac mechanisms are still elusive. This study aims to evaluate the real-time effects of experimentally induced PTSD symptom activation on various cardiac contractility and autonomic measures. We recorded synchronized electrocardiogram and impedance cardiogram from 137 male veterans (17 PTSD, 120 non-PTSD; 48 twin pairs, 41 unpaired singles) during a laboratory-based traumatic reminder stressor. To identify the parameters describing the cardiac mechanisms by which trauma reminders can create stress on the heart, we utilized a feature selection mechanism along with a random forest classifier distinguishing PTSD and non-PTSD. We extracted 99 parameters, including 76 biosignal-based and 23 sociodemographic, medical history, and psychiatric diagnosis features. A subject/twin-wise stratified nested cross-validation procedure was used for parameter tuning and model assessment to identify the important parameters. The identified parameters included biomarkers such as pre-ejection period, acceleration index, velocity index, Heather index, and several physiology-agnostic features. These identified parameters during trauma recall suggested a combination of increased sympathetic nervous system (SNS) activity and deteriorated cardiac contractility that may increase the heart failure risk for PTSD. This indicates that the PTSD symptom activation associates with real-time reductions in several cardiac contractility measures despite SNS activation. This finding may be useful in future cardiac prevention efforts.

Non-hyperaemic coronary flow velocity acceleration indices correlate with hyperaemic microvascular resistance in patients with INOCA

Abstract Background Coronary microvascular dysfunction (CMD) is associated with an overall worse prognosis. While the diagnosis and endo-typing of CMD currently rely on hyperaemic physiological indices, the search for accurate non-hyperaemic techniques continues. Flow velocity acceleration pattern is mechanistically associated with changes in shear stress, endothelial function, arterial stiffness and pressure in pulsatile flow systems (1-3). Purpose We aim to interrogate whether resting flow velocity acceleration indices correlate with hyperaemic microvascular resistance (HMR) in patients with Ischemia and no obstructive coronary artery disease (INOCA). Methods In 21 Patients with INOCA (all of whom had presented with typical angina pectoris, had no significant epicardial stenoses but positive myocardial perfusion scan test for ischemia) invasive physiological assessment was performed by means of intracoronary Doppler. Hyperaemia was induced with intracoronary adenosine administration. Coronary flow reserve (CFR) and HMR were calculated per their definitions. Flow velocity acceleration indices were derived from the first derivative of the averaged resting flow velocity waveforms with respect to time. We have defined 6 wave peaks of interest in all patients (peak diastolic acceleration (initial prominent peak with ventricular relaxation, referred as A), early diastolic deceleration (B), early re-acceleration wave (C), peak presystolic deceleration (seen just before initial systolic acceleration peak, J), initial systolic acceleration peak (X) and pre-diastolic deceleration nadir (Z)) and calculated the ratios between them as well as adjusted them with respect to resting mean flow velocity (Figure 1). Results The mean age was 59 ± 8 years and the majority of the study group was female (%81). Cardiovascular risk factors were common amongst the study group.All patients had CFR &amp;lt; 2.5. Mean CFR and HMR were 2.05 ± 0.32 and 2.20 ± 0.60 mmHg.cm.sec-1 respectively. Raw C peak magnitude was significantly correlated with APVh (rho:-0.457 p:0.037) and HMR (rho:0.612 p:0.004). Adjusting the C magnitudes with APVb at patient level yielded better correlations (APVh rho:-0.496 p:0.022 ; HMR:0.642 p:0.002). The ratio between diastolic reacceleration peak (C) and presystolic peak deceleration (J), C/J , adjusted with the APVb ((C/J)/APVb) showed the most pronounced correlation with HMR (rho: 0.758 p &amp;lt; 0.001) (unadjusted C/J – HMR rho: 0.718 p&amp;lt;0.001)(Figure 2). Conclusion(s) Acceleration characteristics of resting coronary flow velocity correlate with hyperaemic microvascular resistance indicating structurally impaired coronary microcirculation, hence their utilisation may aid developing non-hyperaemic physiological markers for coronary microvascular dysfunction in patients with INOCA.Derived Acceleration WaveformsCorrelations between HMR and C/J Ratio