Frontiers in Physiology

BackgroundThoracic spine mobilization (TSM) has been proposed to influence autonomic nervous system (ANS) activity, yet evidence remains inconsistent and feasibility of standardised protocols is unclear. This study aimed to evaluate whether a randomized TSM protocol can be implemented successfully in healthy participants and to provide preliminary estimates of its effects on heart rate variability (HRV) and heart rate (HR). MethodsA randomized feasibility trial was conducted with healthy young ...

AO_SCPLOWBSTRACTC_SCPLOWO_ST_ABSAimsC_ST_ABSWe aim to develop a patient-specific computational model to predict the risk of Ventricular Tachycardia (VT) in patients with Biventricular Cardiac Resynchronization Therapy (BiV-CRT) device. Patients are indeed at risk of developing arrhythmias due to BiV-CRT pacing, a known potential complication that puts the cardiologist on guard against its prevention. Materials and MethodsWe consider three non-ischemic fibrotic patients. Patient-specific left ve...

BackgroundSpinal cord injury (SCI) above the sixth thoracic spinal cord segment can disrupt autonomic cardiovascular control, leading to increased BP variability (BPV). This study compared BPV, nocturnal dipping patterns, and blood pressure (BP) fluctuations among individuals with cervical SCI (C-SCI), upper-thoracic SCI (UT-SCI), and non-injured controls (NI-C). MethodsUsing 24-hour ambulatory blood pressure monitoring, we analyzed BPV (via standard deviation [SD], coefficient of variation [Co...

Abdominal aortic aneurysms (AAA) affect more than 1% of adults over 50 and carry significant mortality risk. Current surveillance relies on intermittent imaging (ultrasound or MRI) at 6-24 month intervals, which may miss rapid growth acceleration between visits. We investigate the feasibility of continuous aneurysm diameter tracking using photoplethysmography (PPG) signals. Using a one-dimensional hemodynamic model that simulates pulse wave propagation from the heart to the digital artery, we de...

The present study presents a systematic approach for generating data-driven synthetic cerebral aneurysm geometries and evaluating their hemodynamics through computational fluid dynamics. Seven patient-specific aneurysm geometries from the right internal carotid artery were reconstructed from time-of-flight magnetic resonance angiography images and standardized through orientation alignment, followed by non-rigid registration onto a common spherical point cloud as a template. Principal component ...

BackgroundConventional definitions of vasoplegia and cardiogenic shock rely on fixed thresholds for mean arterial pressure (MAP), cardiac index (CI), and systemic vascular resistance (SVR), failing to account for the physiologic interdependence between cardiac output and vascular tone. We propose the Resistance:Flow Ratio (RFR = SVRI/CI) as a continuous, physiologically anchored measure to differentiate vascular versus cardiac dysfunction and to unify compensated, decompensated, and mixed shock ...

Societies are aging rapidly in parallel with the increasingly earlier onset of serious diseases in younger populations. These and other factors are creating a substantial disparity between healthspan, the period of life where an individual is free from serious chronic disease or disability, and lifespan -- expanding the morbidity span. Extending healthspan has thus become a major priority. To pursue an integrated strategy toward healthspan support, we launched DELTA, a prospective, open-label, i...

Background: Pressure volume (PV) loop analysis remains the gold standard for assessing the intrinsic global diastolic properties of the left ventricle (LV). Traditional fitting techniques rely on local, phase-constrained fittings and are limited due to their sensitivity to noise, landmark selection, violation of assumptions, and non-convergence. Objective: To develop and validate DIAPINN, a physics-informed neural network (PINN) framework capable of calculating intrinsic diastolic properties of ...

Computational growth and remodeling (G&R) models have been extentively used to investigate abdominal aortic aneurysm (AAA) progression and to support clinical decision-making. However, the development of robust predictive models is often limited by the scarcity of large-scale longitudinal imaging datasets. In this study, we propose a physics-based G&R framework to simulate AAA shape evolution and generate a virtual cohort of aneurysms, thereby addressing data limitations and enabling integration...

Current clinical risk stratification for thoracic aortic aneurysms (TAA) relies primarily on maximum diameter, which is a poor predictor of rupture. Recent fluid-structure interaction studies have identified a dimensionless "flutter instability parameter" (N{omega} ) that accurately classifies abnormal aortic growth. However, this parameter currently serves as a static diagnostic snapshot. In this work, we propose a proof-of-concept computational framework that links flutter instability to micro...

Purposeto describe HRV metrics in Covid-19 patients at admission in the ICU and its relationship with mortality and invasive mechanical ventilation (IMV). Heart rate variability (HRV) in sitting position in critically ill patients has not been explored. Methodswe conducted a prospective single-centre observational study. Adult patients admitted in the ICU with respiratory failure due to RT-PCR-confirmed SARS-CoV-2 but not under IMV were included. Electrocardiogram was recorded at least for 15 m...

Blood pressure (BP) measurement is crucial for medical care, yet existing BP methods are either invasive, tethered, or suffer from low temporal resolution. Non-invasive continuous BP estimation thus remains a significant challenge. To address these challenges, this work presents a novel, non-invasive, multi-modal sensor designed for continuous blood pressure estimation using multiple biosignal modalities as feature inputs. From these input data, we extract cardiovascular timing intervals (e.g., ...

Peripheral Artery Disease (PAD) remains significantly underdiagnosed even among high-risk populations particularly in primary care and underserved settings due to the dependency on Doppler-based Ankle-Brachial Index (ABI) measurements, which is time-consuming, need a trained personnel and specialized equipment. NerveVue is a novel, portable diagnostic system that integrates photoplethysmography (PPG) and piezoelectric sensors to capture arterial pressure wave form signals from all four limbs sim...

ObjectTransdermal biosensors may provide an alternative to conventional blood-based biomarker measurement. Our purpose was to determine the binary correlation between transdermal (Infrasensor; RCE, Inc, Carlsbad, CA) and conventional blood-based measurements. MethodsThis was a secondary analysis from a previously published observational cardiac troponin I (cTnI) study performed to establish the upper reference level of cTnI, at 10 US hospitals. After obtaining informed consent, 2 cohorts of pat...

Diabetes Mellitus (DM) is a metabolic disorder characterized by hyperglycemia, with type 1 characterized as an autoimmune destruction of pancreatic beta cells and type 2 characterized by insulin resistance with progressive beta cell dysfunction. This study applied an existing binary classification algorithm (ALTARN) to accurately predict DM. ALTARN, as a tabular attention residual neural network, uses residual connection to find complex patterns present in tabular columns. We achieved an average...

IntroductionBlood glucose monitoring is essential for the management of diabetes mellitus. Continuous interstitial glucose (IG) monitoring systems are less invasive than capillary blood glucose (BG) measurements, but their agreement decreases at higher glucose levels. Artificial intelligence (AI) approaches, particularly recurrent neural networks such as long short-term memory (LSTM), have shown potential to model temporal glucose dynamics and correct inter-method discrepancies. Objective: To de...

ObjectiveThis study aimed to characterize the activation of lower urinary tract (LUT) targets in response to pudendal nerve stimulation (PNS) in awake human participants. Materials and MethodsIn this single center study, recruited participants had an implanted pudendal neurostimulator for treatment of their symptoms including overactive bladder, incontinence, urinary retention, and/or pelvic pain. Participants came in for a modified urodynamic study where a multichannel manometry catheter was p...

The electrocardiogram (ECG) is a critical tool in the diagnosis and monitoring of cardiovascular disease. Although traditional 12-lead ECGs offer comprehensive in-sights into the electrical activity of the heart, they typically require clinical settings and expert interpretation, which limits their accessibility. In contrast, smartwatch 1-lead ECGs can be recorded at home, allowing more frequent and rapid monitoring. This opens opportunities not only for early detection but also for enhancing pa...

BackgroundDespite its broadening indications, the implantable cardiac monitor (ICM) records a narrow, nonstandard electrocardiogram (ECG) signal which precludes morphological and functional assessments or the application of 12-lead ECG models. We hypothesize that deep learning can be used to reconstruct 12-lead ECG from a single ICM lead for continuously assessing clinical endpoints outside of rhythm detection alone. ObjectiveTo reconstruct 12-lead ECG from a single ICM lead to detect conductio...

BackgroundDynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) enables non-invasive characterization of carotid atherosclerotic plaque. PurposeTo evaluate the performance and reproducibility of a simplified DCE-MRI quantification method for carotid plaque assessment. MethodsT1-weighted black-blood DCE-MRI of the carotid arteries at 3T was performed at baseline and after six months in patients with mild-to-moderate atherosclerotic lesions in a pilot placebo-controlled randomized trial...