Impedance Cardiography Research Articles

Preconception Physical Exercise Is Associated with Phenotype-Specific Cardiovascular Alterations in Women at Risk for Gestational Hypertensive Disorders.

Background/Objectives: Gestational hypertensive disorders (GHD) pose significant maternal and fetal health risks during pregnancy. Preconception physical exercise has been associated with a lower incidence of GHD, but insights into the cardiovascular mechanisms remain limited. This study aimed to evaluate the effect of preconception physical exercise on the complete cardiovascular functions of women at risk for GHD in a subsequent pregnancy. Methods: A non-invasive hemodynamics assessment of arteries, veins, and the heart was performed on 40 non-pregnant women at risk for developing GHD in a subsequent pregnancy. Measurements of an electrocardiogram Doppler ultrasound, impedance cardiography and bio-impedance spectrum analysis were taken before and after they engaged in physical exercise (30-50 min, 3×/week, 4-6 months). Results: After a mean physical exercise period of 29.80 weeks, the total peripheral resistance (TPR), diastolic blood pressure and mean arterial pressure decreased in the total study population, without changing cardiac output (CO). However, in 42% (9/21) of women categorized with high or low baseline CO (>P75 or <P25 resp.), a shift in CO was observed towards the normal reference interquartile range (P25-P75). This was associated with improved hepatic venous and central arterial hemodynamic functions. Similar changes in TPR occurred in 38% (11/29) of women classified as having low or high baseline TPR. Conclusions: As in pregnancy, output- or resistance-dominant cardiovascular profiles already exist prior to conception. This study illustrates that preconception physical exercise shifts high or low CO and/or TPR towards the normal midrange, allowing women at risk for GHD to start a subsequent pregnancy with a more gestation-adaptable cardiovascular system.

Thoracic fluid content as a useful diagnostic marker of resting dyspnoea in patients hospitalised due to acute heart failure

Background: Dyspnoea is one of the most common symptoms in the emergency department, and identification of its cause may require complex diagnostic tests. In everyday practice, some concerns arise when the reported dyspnoea is not fully compatible with objective measures in additional tests. This study was performed to evaluate which objective diagnostic markers differentiate patients admitted to hospital due to acute heart failure with and without resting dyspnoea, with a special emphasis on haemodynamic parameters measured by impedance cardiography. Methods: This study enrolled patients over 18 years of age who were hospitalised due to acute heart failure. The admission evaluation included haemodynamic profiling by ICG, with special emphasis on parameters characterising afterload (systemic vascular resistance index), cardiac function (cardiac index; stroke index), and congestion (thoracic fluid content). Results: The study population consisted of 102 patients, mostly men (76.5%), with a mean age of 71.4 ± 12.5 years and a left ventricle ejection fraction of 37.3 ± 14.1%. Patients with dyspnoea at rest (n = 41), in comparison with those without this symptom (n = 61), presented with poorer clinical states: more frequent orthopnoea (p = 0.002), tachypnoea (p = 0.001), palpitations (p = 0.004), and peripheral hypoperfusion (p = 0.0005), higher concentration of high-sensitivity troponin T (p = 0.021), and higher thoracic fluid content (p = 0.003). No significant differences were noted for haemoglobin, creatinine, N-terminal pro-brain natriuretic peptide, heart rate, blood pressure, chest X-ray, left ventricular ejection fraction, cardiac index, stroke index, or systemic vascular resistance index. Conclusions: Thoracic fluid content assessed by impedance cardiography was found to be a good diagnostic marker for differentiating patients admitted to hospital due to acute heart failure with and without resting dyspnoea, and was superior to chest X-rays, N-terminal pro-brain natriuretic peptide, and left ventricle ejection fraction.

Targeted Treatment Reverses Increased Left Cardiac Work in Unilateral vs. Bilateral Primary Aldosteronism.

The incidence of cardiovascular complications may be higher in unilateral than bilateral primary aldosteronism (PA). We compared noninvasive hemodynamics after targeted therapy of bilateral vs. unilateral PA. Adrenal vein sampling was performed, and hemodynamics recorded using radial artery pulse wave analysis and whole-body impedance cardiography (n = 114). In 40 patients (adrenalectomy n = 20, spironolactone-based treatment n = 20), hemodynamic recordings were performed after 33 months of PA treatment. In initial cross-sectional analysis, 51 patients had bilateral and 63 unilateral PA. The mean ages were 50.6 and 54.3 years (P = 0.081), and body mass indexes 30.3 and 30.6 kg/m2 (P = 0.724), respectively. Aortic blood pressure (BP) and cardiac output did not differ between the groups, but left cardiac work was ~10% higher in unilateral PA (P = 0.022). In the follow-up study, initial and final BPs in the aorta were not significantly different, while initial cardiac output (+13%, P = 0.015) and left cardiac work (+17%, P = 0.009) were higher in unilateral than bilateral PA. After median treatment of 33 months, the differences in cardiac load were abolished, and extracellular water volume was reduced by 1.3 and 1.4 l in bilateral vs. unilateral PA, respectively (P = 0.814). These results suggest that unilateral PA burdens the heart more than bilateral PA, providing a possible explanation for the higher incidence of cardiac complications in unilateral disease. A similar reduction in aldosterone-induced volume excess was obtained with targeted surgical and medical treatment of PA.

Long-term myocardial effects of noninvasive ventilation in patients with obesity hypoventilation syndrome

IntroductionChronic effects of noninvasive ventilation on myocardial function in patients with obesity hypoventilation syndrome (OHS) are scarcely understood. The aim of the present study was to evaluate the long-term effects of volume-targeted bilevel positive airway pressure ventilation (BiPAP) on cardiac parameters and myocardial biomarkers in patients with OHS. MethodsClinically stable patients with OHS referred to the tertiary center for the initiation of long-term BiPAP therapy were consecutively enrolled. At baseline, all participants underwent overnight cardiorespiratory polygraphy. BiPAP therapy using volume-targeted spontaneous/timed mode delivered via an oro-nasal mask was initiated. Beat-to-beat noninvasive monitoring by impedance cardiography was used to assess heart function at baseline and after 3 and 12 months of BiPAP use. Serum troponin 1, N-Terminal Pro-B-Type Natriuretic Peptide (NT-ProBNP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) were monitored. ResultsThirteen patients (10 men; mean age, 55.8 ± 9.8 years; mean body mass index of 47.8 ± 5.9 kg/m2) were recruited. From baseline to 3, and to 12 months of BiPAP use, left ventricular stroke volume (SV), ejection time (LVET), and ejection time index significantly increased (P = 0.030; P < 0.001; P = 0.003, respectively), while heart rate and systolic time ratio significantly decreased (P = 0.004; P = 0.034, respectively). Reductions in serum NT-proBNP, IL-6 and TNF-α were observed (P = 0.045; P = 0.018; P = 0.003, respectively). No significant changes in serum troponin were detected throughout the study. ConclusionsThe present findings of increased SV, in association with lengthening of LVET, reductions of NT-proBNP and reductions in circulatory inflammatory markers in patients with stable OHS and chronic moderate-to-severe daytime hypercapnia treated with BiPAP over 1 year support the role of this therapeutic mode in such patients.

Differential hemodynamic adaptations to tilt test in patients with idiopathic atrial fibrillation

AbstractThe hemodynamic response during the transition from the supine to standing position in idiopathic atrial fibrillation (AF) patients is not completely understood. This study aimed to analyze the hemodynamic changes that occur during the head‐up tilt test in idiopathic AF patients. We investigated the hemodynamic changes during the head‐up tilt test with impedance cardiography in 40 AF patients (12 with AF rhythm‐AFr and 28 with sinus rhythm‐AFsr) and 38 non‐AF controls. Patients with AFr had attenuated SVI decrease after standing when compared to AFsr and non‐AF [ΔSVI in mL/m2: −1.3 (−3.4 to 1.7) vs. −6.4 (−17.3 to −0.1) vs. −11.8 (−18.7 to −8.0), respectively; p &lt; 0.001]. PVRI decreased in AFr but increased in AFsr and non‐AF [ΔPVRI in dyne.seg.m2/cm5: −477 (−1148 to 82.5) vs. 131 (−525 to 887) vs. 357 (−29 to 681), respectively; p &lt; 0.01]. Similarly, compared with non‐AF patients, AFr patients also had a greater HR and greater CI increase after standing. The haemodynamic response to orthostatic challenge suggests differential adaptations between patients with AF rhythm and those reverted to sinus rhythm or healthy controls. Characterizing the hemodynamic phenotype may be relevant for the individualized treatment of AF patients.

Callous-unemotional traits and pre-ejection period in response to reward.

Callous-unemotional (CU) traits have important utility in distinguishing individuals exhibiting more severe and persistent antisocial behavior, and our understanding of reward processing and CU traits contributes to behavioral modification. However, research on CU traits often investigated reward alongside punishment and examined solely on average reward reactivity, neglecting the reward response pattern over time such as habituation. This study assessed individuals' pre-ejection period (PEP), a sympathetic nervous system cardiac-linked biomarker with specificity to reward, during a simple reward task to investigate the association between CU traits and both average reward reactivity and reward response pattern over time (captured as responding trajectory). A heterogeneous sample of 126 adult males was recruited from a major metropolitan area in the US. Participants reported their CU traits using the Inventory of Callous-Unemotional Traits and completed a simple reward task while impedance cardiography and electrocardiogram were recorded to derive PEP. The results revealed no significant association between average PEP reward reactivity and CU traits. However, CU traits predicted both linear and quadratic slopes of the PEP reactivity trajectory: individuals with higher CU traits had slower habituation initially, followed by a rapid habituation in later blocks. Findings highlight the importance of modeling the trajectory of PEP reward response when studying CU traits. We discussed the implications of individuals with high CU traits having the responding pattern of slower initial habituation followed by rapid habituation to reward and the possible mechanisms.

Continuous non-invasive measurement of cardiac output in neonatal intensive care using regional impedance cardiography: a prospective observational study

ObjectivesTo compare agreement between echocardiography and regional impedance cardiography (RIC)-derived cardiac output (CO), and to construct indicative normative ranges of CO for gestational age groups.Design, setting and participantsProspective cohort observational...

Central sleep apnea in chronic heart failure with hypoxemia - treatment efficacy and hemodynamic effects of three different treatment modalities: a case report

BackgroundThe optimal treatment for central sleep apnea (CSA) depends on the underlying pathophysiology and should consider the potential for hemodynamic impairment when using positive airway pressure devices. While the long-term effects on overall cardiovascular outcome have been investigated for different device settings, the immediate hemodynamic consequences are not well understood. This is mainly due to a lack of hemodynamic monitoring during routine polysomnographic assessment. The application of most monitoring devices is either restricted by their invasiveness, e.g. in thermodilution, or cannot be used continuously like in echocardiography. Impedance cardiography (ICG), however, enables physicians to implement a continuous non-invasive monitoring of different hemodynamic parameters which can be useful in various clinical scenarios. In sleep medicine, the hemodynamic effect of initiating positive airway pressure treatment in patients with pre-existing heart failure should be of special concern.Case presentationIn this case report, we compare the efficacy of three different treatment modalities in a patient with CSA related to chronic heart failure considering the resolution of respiratory events on polysomnography (PSG). In addition, we outline the hemodynamic effects of each treatment device using ICG for non-invasive hemodynamic monitoring. Regarding the reduction of respiratory central events, long-term oxygen treatment (LTOT) and adaptive servoventilation (ASV) proved to be more efficient compared with automatic positive airway pressure (APAP). Hemodynamically, substantial differences of the cardiac performance were observed between the treatment devices. This especially applied to ASV which led to a pronounced drop in cardiac output.ConclusionOur case report indicates that treatment of CSA may induce significant changes of hemodynamic parameters which would remain undetected during routine polysomnographic assessment. We conclude that non-invasive hemodynamic monitoring may be considered when positive airway pressure treatment is initiated in patients at risk of hemodynamic impairment.

Initializing the weights of a multilayer perceptron for activity and emotion recognition

Conducting an analysis of human behavior is an intriguing topic for many researchers. Within this field, machine learning can be applied to classify activities and emotions by analyzing physiological signals. However, the limited size of available databases poses challenges for the generalization of classifiers. This paper proposes a method to enhance the generalization of neural network-based classifiers by intelligently initializing weights for emotion and activity recognition. The signals under consideration are electrocardiogram, thoracic electrical bioimpedance, and electrodermal activity. The database used comprises recordings from 40 subjects performing various tasks that induce emotions and activities. The performance of the proposed method is compared with several standard machine learning and deep learning classifiers typically employed in emotion and activity recognition. This study involves two primary assessments. First is the activity recognition task, encompassing classes such as neutral, emotional, mental, and physical activity, where results close to 20% accuracy are achieved using the three physiological signals. Second, the emotion recognition assessment aims to differentiate between emotions like neutral, sadness, and disgust. An error probability close to 15% is obtained using thoracic electrical bioimpedance and electrodermal activity. The proposed method yields the best results among the approaches evaluated.

#3050 Hemodynamic study of hypertensive disorders in pregnancy using cardiothoracic bioimpedance

Abstract Background and Aims Hypertensive disorders in pregnancy (HDP) are a major cause of maternal and perinatal morbidity and mortality. There is still a need for the development of biomarkers for early diagnosis of the severity of the condition. Thoracic electrical bioimpedance (TEB) is a non-invasive hemodynamic technique based on the resistance to the flow of electrical current. We investigated hemodynamic changes in pregnant/postpartum women with HDP using TEB. Method A retrospective observational study was conducted in pregnant and postpartum women with hypertension monitored by TEB. Indirect changes were analyzed in: cardiac work, left cardiac work index (LCWI kg⋅m/m2) and calculated cardiac output (CO ml/min=systolic volume -SV ml- × heart rate -HR bpm-); fluid status, thoracic fluid content index (TFCI l/kOhm/m2); and resistances, systemic vascular resistance index (SVRI dyn.s.cm-5.m2). Normality of variables was assessed by Shapiro-Wilk test and correlation analysis was performed by Pearson/Spearman tests. Statistical inference between the hypertension-preeclampsia and pregnancy-postpartum groups was performed using Student's/Mann-Whitney U tests. Analysis was performed using STATA 12. Results Fifty-five patients were included with a mean age of 36.5 years (SD 4.54), 69% were older than 35 years. Pregnant women accounted for 86% of the TEB evaluations, the majority (93.6%) in the third trimester. There was chronic hypertension in 7.27% and pre-eclampsia in 18.18% of previous pregnancies. The diagnoses were: pre-eclampsia (56.36%), gestational hypertension (40%) and HELLP syndrome (3.64%). The mean blood pressure was 144/89 (SD 16/11) mmHg. Mean proteinuria was 363.2 (range: 10.3-23220) mg/g. The median values were as follow: LCWI: 5.05 (IQR: 1.4) kg⋅m/m2; CO: 6352 (IQR: 2345) ml/min; TFCI: 17.9 (IQR: 6.3) l/kOhm/m2; SVRI: 2167.63 (SD: 462.87) dyn.s.cm-5.m2. LCWI showed a weak positive correlation with systolic blood pressure (SBP) and a strong correlation with diastolic blood pressure (DBP) (Rho 0.2899 and 0.5176, respectively). There was also a positive and moderate correlation between SVRI and SBP and DBP (r 0.4265 and 0.4019, respectively). There was no correlation between CO or TFCI and SBP or DBP. No statistically significant differences in hemodynamic parameters were found between gestational hypertension and pre-eclampsia, nor between pregnant and postpartum women. Conclusion Increased blood pressure in the setting of HDP correlates with increased LCWI and systemic resistance independent of fluid retention. An increase in systemic vascular resistance measured by TEB (which decreases in normal pregnancy) may be an early diagnostic marker of HDP. These findings require further validation in a larger cohort, including a control group of pregnant women without hypertension.

Association between arterial health and cognition in adolescents: The PANIC study.

We investigated the associations of the measures of arterial health with cognition in adolescents and whether physical activity (PA) or sedentary time (ST) confounds these associations. One hundred sixteen adolescents (71 boys) aged 15.9 ± 0.4 participated in the study. PA and ST were assessed using a combined accelerometer/heart rate monitor. Overall cognition was computed from the results of psychomotor function, attention, working memory, and paired-associate learning tests. Pulse wave velocity was measured by impedance cardiography, carotid intima-media thickness, and carotid artery distensibility by carotid ultrasonography. Systolic and diastolic blood pressure (SBP and DBP) were measured using an aneroid sphygmomanometer. SBP was inversely associated with overall cognition (standardized regression coefficient [β] = -0.216, 95% confidence interval (CI) -0.406 to -0.027, p = 0.025). Pulse wave velocity (β = -0.199, 95% CI -0.382 to -0.017, p = 0.033) was inversely associated with working memory task accuracy. SBP was directly associated with reaction time in the attention (β = 0.256, 95% CI 0.069 to 0.443, p = 0.008) and errors in the paired-associate learning tasks (β = 0.308, 95% CI 0.126 to 0.489, p = 0.001). Blood pressure was inversely associated with overall cognition. PA or ST did not confound the associations. Results suggest that preventing high blood pressure is important for promoting cognition in adolescents.

Chronic Cervical Midline Contusion in Rats Disrupts Multiple Facets of Cardiovascular Function

Cardiovascular dysfunction is the leading cause of morbidity and mortality following spinal cord injury (SCI). There are a limited number of studies assessing cardiovascular deficits after cervical SCI. This study aimed to assess disrupted cardiovascular function following a chronic severe incomplete C8 SCI in rats, via damaging descending sympathetic projections to the spinal sympathetic preganglionic neurons. Rats were first trained on the isometric pull task before receiving a C8 midline contusion (Infinite Horizon Impact Device; 250 kilodynes; 0 s dwell time) or laminectomy and were tested one day per week from weeks 7-13 following surgery. Isometric forelimb strength and correlates of muscle endurance were monitored during pull task sessions. Cardiovascular function was evaluated 16 weeks post-surgery. Tilt table testing was used to induce an orthostatic challenge by tilting rats 90 degrees head-up from a supine position and 90 degrees head-down from supine position as a control. Following tilt table testing, dobutamine (DOB; 2 μg/kg/min and 10 μg/kg/min) and norepinephrine (NE; 1 μg/kg/min and 4 μg/kg/min) were infused into the femoral vein separately to assess cardiovascular responses to a pharmacological challenge. We monitored cardiovascular physiology during all terminal testing. A blood pressure catheter was inserted into the left common carotid artery and advanced to the aortic arch to monitor interatrial blood pressure, 2 pairs of impedance cardiography (ICG) electrodes were placed on the left side of the thorax to evaluate inotropic correlates of cardiac function, and 2 photoplethysmography (PPG) sensors were affxed over the forelimbs flexor muscles to examine peripheral hemodynamics. To verify the accuracy of ICG-derived cardiac function, rats were examined by echocardiography at week 15. Spinal cords were collected for lesion analysis and were also stained for tyrosine hydroxylase. Our preliminary results demonstrate that chronic severe incomplete C8 SCI resulted in a significant and sustained hypotension during the 3-minute period of 90 degrees head-up tilting (systolic blood pressure = ~ -22 mmHg; diastolic blood pressure = ~ -19 mmHg) compared to laminectomy. There were also significant differences in left ventricular ejection time, heart rate, and stroke volume across groups, whereas forelimb hemodynamics did not differ across groups. Additionally, correlates of forelimb muscle endurance significantly decreased in SCI rats, despite similar isometric forelimb strength across groups. Intravenous infusion of DOB and NE demonstrated significant and dose-dependent effects on cardiovascular parameters. Overall, our data demonstrate that chronic severe C8 SCI in rats leads to orthostatic hypotension and also impairs multiple additional aspects of function. This study was supported by: NIH (R01 NS131493) and Florida Department of Health (COPBC). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Contributors to Diminished Cardiorespiratory Fitness in Young Users of Electronic Cigarettes

Background: Cardiorespiratory fitness, an independent marker of cardiovascular health, represents the ability of respiratory, cardiovascular, and muscular systems to effciently deliver and utilize oxygen (O2) during exercise. Recently, reduced cardiorespiratory fitness was identified in young and healthy, regular users of electronic (e-) cigarettes; however, its limiting factors are not established. Thus, the purpose of this study was to investigate the contributors to impaired cardiorespiratory fitness in young regular users of e-cigarettes. Methods: An evaluation of hemodynamics, chronotropic response, and oxygen utilization during exercise was completed in nineteen regular users of e-cigarettes (EU, age: 23±3 yr; e-cigarette usage 4±2 yr.) and sixteen demographically matched non-users (NU, age: 23±3 yr.). Hemodynamics were accessed via a non-invasive signal morphology impedance cardiography device, while chronotropic responses were measured as changes in peak heart rate (HR). Oxygen extraction ratio (difference in arterial and venous O2 content) at baseline and peak exercise was also recorded. Fold changes from rest to peak exercise were assessed to provide insight into potential factors that limit cardiorespiratory fitness. Results: At peak exercise, users of e-cigarettes exhibited significantly higher chronotropic incompetence ( p=0.033) and lower ( p=0.047) peak HR than non-users, with no differences in other hemodynamic assessments. Significantly ( p=0.025) lower skeletal muscle O2 extraction (EU=51±11 vs. NU=61±10%) was also observed in users of e-cigarettes during peak exercise. Fold changes in chronotropic (HR; p=0.915) and hemodynamic (cardiac output; p=0.279) responses were similar between both groups, while significant ( p=0.048) differences in oxygen extraction ratio were identified between the users of e-cigarettes (0.5±0.3 fold change) and non-users (0.8±0.3 fold change). Conclusions: Results from our study demonstrate that young, regular users of e-cigarettes exhibit abnormal chronotropic responses and impaired skeletal muscle oxygen utilization during exercise when compared to non-users, suggesting reduced cardiovascular and muscle health. Overall, our findings contribute to the growing body of evidence that supports the negative effects of regular e-cigarette use on young individuals. Supported in part by a Rapid Response Project NIDA/FDA (PRM). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Optimal homeostatic stress to maximize the homogeneity of adaptations to interval interventions in soccer players.

This study examined the uniformity of adaptations in cardiorespiratory fitness and bio-motor abilities by analyzing individual responses to measures representing the mentioned qualities. Twenty-four male well-trained soccer players (Age = 26 ± 4years; stature = 181 ± 3.8; Weight = 84 ± 6.1) were randomized to two groups performing short sprint interval training [sSIT (3 sets of 10 × 4s all-out sprints with 20s of recovery between efforts and 3min of rest intervals between sets)] or a time-matched small-sided game [SSG (3 sets of 3 v 3 efforts in a 20 × 15m area with 3min of relief in-between)]. Before and after the 6-week training period, aerobic fitness indices, cardiac hemodynamics, and anaerobic power were assessed through a graded exercise test utilizing a gas collection system, noninvasive impedance cardiography, and a lower-body Wingate test, respectively. Also, sport-specific bio-motor abilities were determined by measuring linear speed, change of direction, and jumping ability. Comparing inter-individual variability in the adaptive changes by analyzing residuals in individual adaptations indicated that sSIT induces more uniform changes in the first and second ventilatory threshold (VT1 & VT2), stroke volume, and peak power output across team members than SSG. SSG also yielded lower proportions of responders in , VT1, VT2, peak, and average power output compared to sSIT. Additionally, the coefficient of variation in mean group changes in measures of aerobic fitness and bio-motor abilities in response to sSIT were lower than in SSG. Short sprint interval training induces more homogenized adaptations in measures of cardiorespiratory fitness and anaerobic power than small-sided games across team members.

ASIC design of power and area efficient programmable FIR filter using optimized Urdhva-Tiryagbhyam Multiplier for impedance cardiography

Impedance cardiography (ICG) is a rapidly growing non-invasive cardiac health monitoring approach. Synchronous detection of ICG requires an FIR filter to remove the high-frequency carrier signal. Low power consumption and compact area are critical considerations in the design of portable biomedical systems. This paper proposes a novel product quantization-based optimization strategy for the Urdhva Tiryagbhyam Sutra-based multiplier architecture. This paper presents an ASIC design of a low-power and low-area 64th-order programmable FIR filter architecture using the optimized Urdhva Tiryagbhyam Multiplier. The programmable architecture empowers medical practitioners to select the carrier frequency at which the ICG analysis will be performed. The elimination of redundant multipliers from the design based on the filter coefficients is demonstrated. The programmable Vedic FIR filter architecture (described in VHDL) is implemented on the Basys-3 FPGA board for rapid prototyping. The RTL-to-GDSII flow has been completed using Cadence digital design and sign-off tools for the SCL-180 nm technology. The results indicate that the proposed filter architecture occupies 41.33% less area and 42.16% lower power consumption than the contemporary designs described in the literature.

Cardiac hemodynamics phenotypes and individual responses to training in coronary heart disease patients.

In patients with coronary heart disease (CHD), individualized exercise training (ET) programs are strongly recommended to optimize peak oxygen uptake ( O2peak) improvement and prognosis. However, the cardiac hemodynamic factors responsible for a positive response to training remain unclear. The aim of this study was to compare cardiac hemodynamic changes after an ET program in responder (R) versus non-responder (NR) CHD patients. A total of 72 CHD patients completed a 3-month ET program and were assessed by cycle ergometer cardiopulmonary exercise test (CPET: O2peak assessment) with impedance cardiography (ICG) for hemodynamic measurements before and after training. Cardiac hemodynamics (e.g., CO, CI, SV, ESV, EDV, and SVR) were measured by ICG during CPET. The R and NR groups were classified using the median change in O2peak (>the median for R and ≤the median for NR). In the R group, O2peak (+17%, p < 0.001), CO, CI, SV, and HR increased by 17%, 17%, 13%, and 5%, respectively (p < 0.05) after the training program. In the NR group, O2peak, CO, CI, and SV increased by 0.5%, 5%, 8%, and 6%, respectively (p < 0.01). The SVR decreased in both groups (-19% in R and -11% in NR, p < 0.001). Among CHD patients, the R group showed a better improvement in peak cardiac output via an increase in peak stroke volume and heart rate and a reduced systemic vascular resistance than the NR group. Different cardiac phenotype adaptations and clinical individual responses were identified in CHD patients according to the aerobic fitness responder's status.

Electrical cardiometry assessment of cardiac output compared to echocardiography in septic shock patients

Background Cardiac output (CO) measurement is essential for guiding therapeutic decisions in critically ill patients. Electrical cardiometry (EC), which is based on thoracic electrical bioimpedance, can measure CO in a continuous and noninvasive way. The benefits of EC are continuous monitoring, low time consumption, portability, and user independence. Transthoracic echocardiography has been a noninvasive method to assess CO despite being noncontiguous and operator dependent. Aim This study aimed to compare EC and echocardiography (Echo) in measuring CO in septic shock patients and assess the reliability and accuracy of EC for noninvasive CO monitoring. Patients and methods Fifty adult patients were admitted to the Critical Care Medicine Department, diagnosed with septic shock according to the surviving sepsis campaign, and fulfilling the inclusion and exclusion criteria from January 2023 to October 2023, and they were subjected to EC, Echo, and ECG recording. Results There was a strong positive significant correlation between CO measurements by echo and EC (r=0.988, P&lt;0.001), and there was a strong positive significant correlation between stroke volume (SV) measurements by echo and EC (r=0.999, P&lt;0.001). Also, there was a strong positive significant correlation between SV and CO measured by both techniques (r=0.782, P&lt;0.001) (r=0.790, P&lt;0.001, respectively). Conclusion Compared to Echo, EC can be used as a continuous, noninvasive method for monitoring CO and SV, as it provides accurate and reliable measurements.

Sacubitril/valsartan reversal of left ventricular remodeling is associated with improved hemodynamics in resistant hypertension

BackgroundSacubitril/valsartan (S/V) has been shown to be an effective antihypertensive drug combination. However, its therapeutic effects on blood pressure (BP), hemodynamics, and left ventricular (LV) remodeling in resistant hypertension (RHTN) remain unclear. MethodsEighty-six patients completed this self-control study, during which olmesartan was administered within the first 8 weeks (phase 1), followed by S/V within the second 8 weeks (phase 2), with nifedipine and hydrochlorothiazide taken as background medications. Office BP, echocardiography, and hemodynamics assessment using impedance cardiography were performed at baseline and at the eighth and sixteenth weeks. ResultsThe reduction in office BP was larger in phase 2 than in phase 1 (19.59/11.66 mmHg vs. 2.88/1.15 mmHg). Furthermore, the treatment in phase 2 provided greater reductions in systemic vascular resistance index (SVRI) and thoracic blood saturation ratio (TBR), with differences between the two phases of −226.59 (−1212.80 to 509.55) dyn·s/cm5/m2 and −0.02 (−0.04 to 0.02). Switching from olmesartan to S/V also significantly reduced E/E′, LV mass index, LV end-diastolic volume index, and LV end-systolic volume index (all P < 0.05). Decreases in arterial stiffness, SVRI, and TBR were correlated with changes in indicators of LV remodeling (all P < 0.05). This correlation persisted even after adjusting for confounders including changes in BP. ConclusionsSwitching from olmesartan to S/V effectively lowered BP and reversed ventricular remodeling in RHTN. In addition, hemodynamic improvement was also observed. Changes in hemodynamics played an important role in reversing LV remodeling of S/V, and were independent of its antihypertensive effect.

Accumulating Sedentary Time and Physical Activity From Childhood to Adolescence and Cardiac Function in Adolescence.

Increased physical activity (PA) may mitigate the negative cardiovascular health effects of sedentary behavior in adolescents. However, the relationship of PA and sedentary time from childhood with cardiac function in adolescence remains underexplored. Therefore, we investigated the associations of cumulative sedentary time and PA from childhood to adolescence with cardiac function in adolescence. Participants were 153 adolescents (69 girls) who were aged 6 to 8 years at baseline, 8 to 10 years at 2-year follow-up, and 15 to 17 years at 8-year follow-up. Cumulative sedentary time and PA exposure between baseline and 2-year follow-up and between baseline and 8-year follow-up were measured using a combined accelerometer and heart rate monitor. Cardiac function was assessed using impedance cardiography at 8-year follow-up. The data were analyzed using linear regression analyses adjusted for age and sex. Cumulative moderate to vigorous PA (standardized regression coefficient [β]=-0.323 [95% CI, -0.527 to -0.119]) and vigorous PA (β=-0.295 [95% CI, -0.508 to -0.083]) from baseline to 8-year follow-up were inversely associated with cardiac work at 8-year follow-up. Conversely, cumulative sedentary time had a positive association (β=0.245 [95% CI, 0.092-0.398]). Cumulative vigorous PA from baseline to 8-year follow-up was inversely associated with cardiac work index at 8-year follow-up (β=-0.218 [95% CI, -0.436 to 0.000]). Higher levels of sedentary time and lower levels of PA during childhood were associated with higher cardiac work in adolescence, highlighting the importance of increasing PA and reducing sedentary time from childhood.

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.