Search Results (45)

Background: Patent ductus arteriosus (PDA) in dogs causes persistent left-to-right shunting, leading to pulmonary overcirculation, left heart volume overload, and potential congestive heart failure. Accurate assessment of fluid imbalance is essential but challenging with conventional echocardiography or biomarkers. Phase angle (PhA), derived from bioelectrical impedance analysis (BIA), may serve as a non-invasive marker of extracellular fluid distribution and cellular integrity. Objectives: This study aimed to evaluate PhA as an indicator of thoracic fluid imbalance in dogs with PDAby analyzing its correlation with pulmonary velocity (PV) and end-diastolic volume (eV), as well as its responsiveness to surgical correction. In addition, we assessed the relationships between PhA and echocardiographic structural indices (LA/Ao, TDI Sep E/Em, TDI Lat E/Em) and examined the influence of the measurement region. Methods: PhA was measured at 5, 50, and 250 kHz in 30 PDA-affected and 15 healthy dogs, with electrode placement across thorax, trunk, and abdomen. Echocardiography evaluated PV, eV, and PDA-specific structural parameters. Results: Thoracic PhA at 5 kHz was significantly reduced in PDAdogs, strongly correlated with PV and moderately with eV. Postoperative measurements showed progressive PhA recovery. Only TDI Lat E/Em correlated with mid-frequency PhA, while other structural indices showed minimal association. Thoracic PhA was lower than trunk or abdominal values, indicating that thoracic measurements may better capture localized extracellular fluid changes in PDAcompared with other regions. Conclusion: Thoracic PhA at 5 kHz effectively reflects extracellular fluid changes in PDA, complements structural echocardiography, and tracks postoperative fluid normalization. Its non-invasive nature supports clinical utility for monitoring hemodynamic burden and therapeutic response. Full article

Background: Sarcopenia and low muscle mass are prevalent and prognostically relevant in patients with lung cancer, yet their diagnosis remains challenging in routine clinical practice. Opportunistic assessment using computed tomography (CT) has emerged as a valuable tool for body composition evaluation. We aimed to assess the utility of thoracic CT at T12 and T4 levels in identifying sarcopenia and low muscle mass and explore their correlation with morphofunctional tools such as bioelectrical impedance vector analysis (BIVA), nutritional ultrasound (NU), and functional performance tests. Methods: In this prospective observational study, 80 patients with lung cancer were evaluated at diagnosis. Body composition was assessed using BIVA-, NU-, and CT-derived parameters at T12 and T4 levels. Functional status was measured using the Timed Up and Go (TUG) and 30-Second Chair Stand Test. Sarcopenia was defined according to EWGSOP2 criteria. Results: Sarcopenia was identified in 20% of patients. CT-derived indices at T12CT demonstrated better diagnostic performance than T4CT. For detecting low muscle mass, the optimal SMI cut-off values were SMI_T12CT < 31.98 cm²/m² and SMI_T4CT < 59.05 cm²/m² in men and SMI_T12CT < 28.23 cm²/m² and SMI_T4CT < 41.69 cm²/m² in women. For sarcopenia diagnosis, the values were SMI_T12CT < 24.78 cm²/m² and SMI_T4CT < 57.23 cm²/m² in men and SMI_T12CT < 21.24 cm²/m² and SMI_T4CT < 49.35 cm²/m² in women. A combined model including SMI_T12CT, RF_CSA, and the 30 s squat test showed high diagnostic accuracy (AUC = 0.826). In multivariable analysis, lower SMA_T12CT was independently associated with risk of sarcopenia (OR = 0.96, 95% CI: 0.92–0.99, p = 0.022), as were older age (OR = 1.23, 95% CI: 1.07–1.47, p = 0.010) and fewer repetitions in the 30 s squat test (OR = 0.78, 95% CI: 0.63–0.91, p = 0.007). Conclusions: CT-derived body composition assessment, particularly at the T12 level, shows good correlation with morphofunctional tools and may offer a reliable and timely alternative for identifying sarcopenia and low muscle mass in patients with lung cancer. Full article

Background: Computed Tomography (CT) is considered a highly accurate tool for assessing body composition. The aim of this study is to assess the usefulness of chest CT for malnutrition diagnosis in people with cystic fibrosis (PwCF), compared with other body composition techniques, as well as to assess possible associations with nutritional and respiratory status. Methods: A cross-sectional study was carried out in clinically stable adult PwCF. Subjects who had undergone a CT including the twelfth thoracic vertebra (T12) during the 6 months prior to or after our assessment were included and body composition was assessed using FocusedON-BC. The results were compared with anthropometry, bioelectrical impedance analysis (BIA), muscle ultrasonography, and handgrip strength (HGS). Respiratory parameters were collected, and nutritional status was assessed using Global Leadership Initiative on Malnutrition (GLIM) criteria. Results: A total of 55 PwCF were included. Muscle area assessed by CT correlated significantly with fat-free mass determined by BIA (r = 0.725) and anthropometry (r = 0.645), muscle mass evaluated by ultrasonography (r = 0.657), HGS (r = 0.593), Bhalla score (r = 0.403), and FEV1 (r = 0.488). Differences were observed when comparing muscle area in CT based on the Bhalla score (94.6 ± 21.1 cm² in normal/mild involvement vs. 79.3 ± 20.9 cm² in moderate/severe involvement; p = 0.009) and on nutritional status (96.3 ± 17.9 cm² in normo-nourished vs. 75.9 ± 22.1 cm² in malnourished; p < 0.001). Conclusions: In adult PwCF, measurements obtained from CT image analysis correlate adequately with anthropometry, BIA, muscle ultrasound, and HGS. Muscle area in CT is related to nutritional and respiratory status. Full article

Thoracic electrical impedance tomography (EIT) provides real-time, bedside imaging of pulmonary function and has demonstrated significant clinical value in guiding treatment strategies for critically ill patients. However, the practical application of EIT remains challenging due to its susceptibility to measurement disturbances, such as electrode contact problems and patient movement. These disturbances often manifest as spike-like noise that can severely degrade EIT image quality. To address this issue, we propose a robust Principal Component Analysis (RPCA)-based approach that models EIT data as the sum of a low-rank matrix and a sparse matrix. The low-rank matrix captures the underlying physiological signals, while the sparse matrix contains spike-like noise components. In simulation studies considering different spike magnitudes, widths and channels, all the image correlation coefficients between RPCA-processed images and the ground truth exceeded 0.99, and the image error of the original fEIT image with spike-like noise was much larger than that after RPCA processing. In eight patient cases, RPCA significantly improved the image quality (image error: p < 0.001; image correlation coefficient: p < 0.001) and enhanced the clinical EIT-based indexes accuracy (p < 0.001). Therefore, we conclude that RPCA is a promising technique for reducing spike-like noise in clinical EIT data, thereby improving data quality and potentially facilitating broader clinical application of EIT. Full article

Background/Objectives: Accurate measurement of respiratory rate (RR) is critical for early detection of patient deterioration. A newly developed contactless card-type device measures RR and heart rate (HR) by detecting chest impedance changes. Although previously validated in mechanically ventilated patients with 15% RR accuracy, its performance in spontaneously breathing patients remains uncertain. Methods: This prospective observational study was conducted at the Department of Emergency and Critical Care Medicine, Shimane University Hospital, in December 2022. Patients admitted to the emergency center without invasive mechanical ventilation were enrolled. The card-type device was subsequently placed on the left chest, while the RR and HR were simultaneously recorded with an electrocardiogram monitor. Data from both devices were collected and compared. Results: Six patients were enrolled. The RR measurements from the card-type device were within a 10% difference from those measured using the standard monitor in four out of six cases. In two cases, the card-type device recorded an RR lower than that of the standard monitor, which coincided with periods of patient speaking. For HR, the card-type device was within a 10% margin of the standard monitor in two cases, but it underestimated HR in the remaining four cases, particularly during high tidal volumes or increased thoracic thickness. Conclusions: The contactless card-type device accurately measured respiratory rates within a 10% margin compared to standard monitors in most non-intubated patients, except during activities such as speaking. Further studies with larger sample sizes are warranted to confirm these findings and improve the device’s performance. Full article

Background: SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection may be associated with impaired cardiac function, especially in severe cases requiring hospitalization. Impedance cardiography (ICG) is a noninvasive method for assessing cardiac function. It could be useful for the early detection of hemodynamic dysfunction, particularly in patients with a severe course of COVID-19. Aim: This study aimed to analyze and compare the hemodynamic profiles of patients hospitalized with SARS-CoV-2-induced pneumonia to those of a control group. Methods: This prospective, observational, clinical study included 30 hospitalized patients (both men and women, mean age: 48 years) diagnosed with COVID-19 pneumonia (COVID group). Their data were compared to those of a retrospective control group (CG). The study participants were propensity score-matched based on clinical characteristics, including age, blood pressure (BP), and body mass index (BMI). ICG measurements of hemodynamic profiles were performed using a Niccomo device and included heart rate (HR), stroke volume index (SI), cardiac index (CI), velocity index (VI), acceleration index (ACI), Heather index (HI), systemic vascular resistance index (SVRI), and thoracic fluid content (TFC). Results: Patients with COVID-19 showed significantly higher HR (p < 0.0001) and SVRI (p = 0.0003) and lower values for several cardiac function parameters, including SI (p < 0.0001), VI (p < 0.0001), ACI (p = 0.004), and HI (p < 0.0001). Additionally, 11 patients (37%) in the COVID group had a low SI (<35 mL/m²), compared to only 1 patient (3%) in the control group (p < 0.0001). A statistically significant difference in left ventricular ejection fraction (LVEF) was also observed (p < 0.0001), although absolute values remained within the normal range. Conclusions: SARS-CoV-2 infection negatively affects the cardiovascular system, leading to impaired heart function even in low-risk patients. Impedance cardiography may serve as a simple, noninvasive tool for identifying individuals with cardiac dysfunction following COVID-19 pneumonia. Full article

Background/Introduction: Cardiac implantable electronic devices and their integrated thoracic impedance sensors have been used to detect sleep apnea for over a decade now. Despite their usage in daily clinical practice, there are only limited data on their diagnostic accuracy. Methods: AIRLESS and UPGRADE were prospective investigator-driven trials meant to validate the AP scan^® (Boston Scientific, Marlborough, MA, USA) in heart failure cohorts. Patients, who either fulfilled the criteria for implantation of an implantable cardioverter-defibrillator (ICD), cardiac resynchronization therapy (CRT), or upgrading to CRT according to most recent guidelines at the time of study conduction, were eligible for enrolment. Sleep apnea and its severity, measured by apnea–hypopnea index (AHI), were assessed by polysomnography. For direct comparison, the apnea sensor-derived AP scan^® was used from the identical night. Results: Overall, 80 patients were analyzed. Median AHI was 21.6 events/h (7.1–34.7), while median AP scan^® was 33.0 events/h (26.0–43.0). In the overall cohort, the sensor-derived AP scan^® correlated significantly with the AHI (r = 0.61, p < 0.001) with a mean difference (MD) of −12.6 (95% confidence interval (CI) −38.2 to 13.0). Furthermore, the AP scan^® was found to correlate well with the AHI in patients with obstructive sleep apnea r = 0.73, p = 0.011, MD −5.2, 95% CI −22.7 to 12.3), but not central sleep apnea (r = 0.28, p = 0.348, MD −10.4, 95% CI −35.4 to 14.6). Conclusions: In an exclusive heart failure cohort, the AP scan^® correlated well with the PSG-derived AHI. A similar correlation was found in most subgroups except for patients suffering from central sleep apnea. Full article

Cardiac implantable electronic devices (CIEDs) such as pacemakers and implantable cardioverter-defibrillators (ICDs) are increasingly used in the aging population. Modern CIEDs perform daily measurements, mainly aimed at discovering early signs of battery depletion or electrode dysfunction. Changes in thresholds, intracardiac signals, and pacing impedances can be caused by exacerbation of existing conditions or novel clinical problems. Pacing percentages and heart rate histograms can be used to optimize pacemaker programming, but can also be a measure of altered cardiac health status. Several measurements, such as thoracic impedance and patient activity, have been added to inform practitioners about worsening heart failure. In addition, remote monitoring of daily CIED measurements may accommodate for the prevention of the deterioration of clinical conditions. In this review, we discuss the evidence base of CIED algorithms and suggest how to use standard daily measurements to monitor the cardiac and extracardiac health status of patients with CIEDs. Full article

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. Full article

Background: The main cause of hospitalization in patients with heart failure is hypervolemia. Therefore, the primary treatment strategy involves diuretic therapy using intravenous loop diuretics to achieve decongestion and euvolemia. Some patients with acutely decompensated heart failure (ADHF) do not respond well to diuretic treatment, which may be due to diuretic resistance (DR). Such cases require high doses of diuretic medications and combination therapy with diuretics of different mechanisms of action. Although certain predisposing factors for diuretic resistance have been identified (such as hypotension, type 2 diabetes, impaired renal function, and hyponatremia), further research is needed to identify other pathophysiological markers of DR. Objective: This study aims to identify admission markers that can predict a high requirement for intravenous diuretics in hospitalized patients with decompensated heart failure. Methods: This study included 102 adult patients hospitalized for ADHF. At admission, patients underwent clinical assessment, laboratory parameter evaluation (including the N-terminal prohormone of brain natriuretic peptide [NT-proBNP] levels), and hemodynamic assessment using impedance cardiography (ICG). Hemodynamic profiles were based on the use of parameters such as heart rate (HR), blood pressure (BP), and thoracic fluid content (TFC) as markers of volume status. The analysis included 97 patients with documented doses of intravenous diuretic use. Patients were stratified into two groups based on median diuretic consumption (equivalent to 540 mg of intravenous furosemide): the high-loop diuretic utilization (LDU) group (n = 49) and the low-LDU group (n = 48). Results: Compared to low-LDU patients, high-LDU patients had greater thoracic fluid content at admission, both quantitatively (37.4 ± 8.1 vs. 34.1 ± 6.9 kOhm-1; p = 0.024) and qualitatively (TFC ≥ 35 kOhm-1: 59.2% vs. 33.3%; p = 0.011). Anemia was more common in the high-LDU group (67.4% vs. 43.8%; p = 0.019), as was elevated NT-proBNP (≥median of 3952 pg/mL: 60.4% vs. 37.5%; p = 0.024). High LDU was associated with a significantly longer hospitalization duration (12.9 ± 6.4 vs. 7.0 ± 2.6 days; p < 0.001). Logistic regression analysis identified anemia, elevated NT-proBNP, and high TFC as predictors of high LDU (HR: 2.65, 2.54, and 2.90, respectively). In a multifactorial model, only high TFC remained an independent predictor (HR: 2.60, 95% CI 1.04–6.49; p = 0.038). Conclusions: TFC was the sole independent admission marker of a high requirement for intravenous diuretics in patients hospitalized for decompensated heart failure. An objective assessment of volume status by impedance cardiography may support intensive personalized decongestion therapy. Full article

Regional lung ventilation assessment is a critical tool for the early detection of lung diseases and postoperative evaluation. Biosensor-based impedance measurements, known for their non-invasive nature, among other benefits, have garnered significant attention compared to traditional detection methods that utilize pressure sensors. However, solely utilizing overall thoracic impedance fails to accurately capture changes in regional lung air volume. This study introduces an assessment method for lung ventilation that utilizes impedance data from the five lobes, develops a nonlinear model correlating regional impedance with lung air volume, and formulates an approach to identify regional ventilation obstructions based on impedance variations in affected areas. The electrode configuration for the five lung lobes was established through numerical simulations, revealing a power–function nonlinear relationship between regional impedance and air volume changes. An analysis of 389 pulmonary function tests refined the equations for calculating pulmonary function parameters, taking into account individual differences. Validation tests on 30 cases indicated maximum relative errors of 0.82% for FVC and 0.98% for FEV1, all within the 95% confidence intervals. The index for assessing regional ventilation impairment was corroborated by CT scans in 50 critical care cases, with 10 validation trials showing agreement with CT lesion localization results. Full article

The lung is one of the most vital organs in the human body, and its condition is closely correlated with overall health. Electrical impedance tomography (EIT), as a biomedical imaging technique, often produces low-quality reconstructed images due to its inherent ill-posedness in solving the inverse problem. To address this issue, this paper proposes a soft-threshold region segmentation algorithm with a relaxation factor. This algorithm segments the reconstructed lung images into internal regions, edge regions, and background regions, resulting in clearer boundaries in the reconstructed images. This facilitates the intuitive identification of regions of interest by healthcare professionals. Additionally, this segmentation algorithm is suitably combined with a dimension-reduced Tikhonov regularization algorithm. By utilizing the joint capabilities of these algorithms, the partition points belonging to the background region can be excluded from the sought grayscale vector, thereby improving the ill-posedness of the image reconstruction process and enhancing the quality of image reconstruction. Finally, a 16-electrode human lung EIT simulation model is established for the thoracic region and verified through simulation. Experimental validation is conducted using a human lung tank simulation platform to further demonstrate the effectiveness of the proposed method. Full article

Adults who have had an amputation face barriers to having an active lifestyle which attenuates cardiorespiratory fitness. Prior studies in amputees typically involve treadmill walking or arm ergometry, yet physiological responses to bilateral leg cycling are less understood. This study assessed the hemodynamic and metabolic responses to moderate and vigorous cycle ergometry in men who have had a transtibial amputation (TTA). Five men who had had a unilateral TTA (age = 39 ± 15 yr) and six controls (CONs) without an amputation (age = 31 ± 11 yr) performed two 20 min bouts of cycling differing in intensity. Cardiac output (CO), stroke volume (SV), and oxygen consumption (VO₂) were measured during moderate intensity continuous exercise (MICE) and high intensity interval exercise (HIIE) using thoracic impedance and indirect calorimetry. In response to MICE and HIIE, the HR and VO₂ levels were similar (p > 0.05) between groups. Stroke volume and CO were higher (p < 0.05) in the CONs, which was attributed to their higher body mass. In men with TTAs, HIIE elicited a peak HR = 88%HRmax and substantial blood lactate accumulation, representing vigorous exercise intensity. No adverse events were exhibited in the men with TTAs. The men with TTAs show similar responses to MICE and HIIE versus the CONs. Full article

Cardiovascular disease is one of the leading causes of death in the world. Heart failure is a cardiovascular disease in which the heart is unable to pump sufficient blood to fulfill the body’s requirements and can lead to fluid overload. Traditional solutions are not adequate to address the progression of heart failure. Herein, we report a body-mounted wearable sensor to monitor the parameters related to heart failure. These include heart rate, blood oxygen saturation, thoracic impedance, and activity status. The device is compact and wearable and measures the parameters continuously in real time. The device is an Internet of Things (IoT) device connected with a cloud-based database enabling the parameters to be visualized on a mobile application. Full article

Background: Heart failure (HF) is associated with high mortality, morbidity, and frequent hospitalizations due to acute HF (AHF) and requires immediate diagnosis and individualized therapy. Some differences between acutely decompensated chronic heart failure (ADCHF) and de novo HF (dnHF) patients in terms of clinical profile, comorbidities, and outcomes have been previously identified, but the hemodynamics related to both of these clinical states are still not well recognized. Purpose: To compare patients hospitalized with ADCHF to those with dnHF, with a special emphasis on hemodynamic profiles at admission and changes due to hospital treatment. Methods: This study enrolled patients who were at least 18 years old, hospitalized due to AHF (both ADCHF and dnHF), and who underwent detailed assessments at admission and at discharge. The patients’ hemodynamic profiles were assessed by impedance cardiography (ICG) and characterized in terms of heart rate (HR), blood pressure (BP), systemic vascular resistance index (SVRI), cardiac index (CI), stroke index (SI), and thoracic fluid content (TFC). Results: The study population consisted of 102 patients, most of whom were men (76.5%), with a mean left ventricle ejection fraction (LVEF) of 37.3 ± 14.1%. The dnHF patients were younger than the ADCHF group and more frequently presented with palpitations (p = 0.041) and peripheral hypoperfusion (p = 0.011). In terms of hemodynamics, dnHF was distinguished by higher HR (p = 0.029), diastolic BP (p = 0.029), SVRI (p = 0.013), and TFC (only numeric, p = 0.194) but lower SI (p = 0.043). The effect of hospital treatment on TFC was more pronounced in dnHF than in ADCHF, and this was also true of N-terminal pro-brain natriuretic peptide (NT-proBNP) and body mass. Some intergroup differences in the hemodynamic profile observed at admission persisted until discharge: higher HR (p = 0.002) and SVRI (trend, p = 0.087) but lower SI (p < 0.001) and CI (p = 0.023) in the dnHF group. Conclusions: In comparison to ADCHF, dnHF is associated with greater tachycardia, vasoconstriction, depressed cardiac performance, and congestion. Despite more effective diuretic therapy, other unfavorable hemodynamic features may still be present in dnHF patients at discharge. Full article