Impact of Gravity on Cardiac Hemodynamics (ACUITY)

Effect of Intra-cardiac Hydrostatic Pressure Gradient in Cardiac Filling and Ejection

The goal of this clinical trial is to define and compare pre-load dependance of the cardiac function according to the intracardiac hydrostatic gradient of pressure in healthy and diabetic populations.

Participants will undergo 4 tilt angle and 4 lower body negative pressure intensities during which cardiovascular data will be assessed and a transthoracic echography will be performed.

Study Overview

• Status: Recruiting
• Conditions: Healthy; Diabetes type1
• Intervention / Treatment: Other: Cardiovascular and Baroreflex stimulation by Tilting; Other: Cardiovascular and Baroreflex stimulation by Lower Body Negative Pressure

Detailed Description

Gravitational force affects both the cardiac mass and the thoracic compartment. However, few studies in humans have explored whether the relationship between cardiac function and load-dependence varies according to the orientation of the heart in space (e.g. between the upright and supine positions) and therefore according to gravitational stress.

Thirty-two volunteers (16 healthy subjects and 16 subjects with type I diabetes) will be included in the study. Each subject will be analysed over half a day in the Inserm COMETE laboratory. Measurements of the intra-cardiac hydrostatic pressure gradient (reflecting gravitational force) and indicators of cardiac function will be analysed by transthoracic echocardiography using dedicated post-processing software. These measurements will be compared at identical pre-load on the basis of the relationship between thoracic impedance and angle of vertical inclination using a Tilt Test on the one hand and between thoracic impedance and Lower Body Negative Pressure (LBNP) depression in the supine position on the other. In the supine position, the echocardiogram will be repeated for each subject with different levels of intensity of preload decrease by LBNP up to a maximum of -50 torr, and compared with different angles of vertical inclination head up up to +80° on the Tilt Test.

The study aims to compare the contribution of intra-cardiac hydrostatic force to cardiac filling and ejection mechanics in a population of healthy volunteers and subjects with diabetes.

The goal is to define and compare the pre-load dependence of the cardiac function indices studied according to the anatomical supine posture with zero intra-cardiac hydrostatic gradient with the standing posture during which the hydrostatic force is expressed between the cardiac base and apex. The hypothesis is that cardiac filling and ejection are improved when the longitudinal axis of the heart is anatomically oriented in the standing position compared with the supine position, by restoring the intraventricular hydrostatic pressure gradient. Comparing a group of healthy subjects with a group of subjects with diabetes will enable to assess whether the dependence of cardiac function on the orientation of the heart in space is more marked in the presence of subclinical impairment of myocardial function.

• Study Type: Interventional
• Enrollment (Estimated): 32
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Amir HODZIC, MD PhD; Phone Number: 0231065503; Email: hodzic-a@chu-caen.fr
• Study Contact Backup: Name: Hervé NORMAND, MD PhD; Email: herve.normand@unicaen.fr

Study Locations

• France
  • Caen, France, 14000
    • Recruiting
    • Inserm 1075 Comete, Unicaen
    • Contact: Amir HODZIC, MD PhD; Phone Number: 0231065503; Email: hodzic-a@chu-caen.fr
    • Contact: Hervé NORMAND, MD PhD; Email: herve.normand@unicaen.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Affiliated to the social security system
• Patient informed of the study and having signed an informed consent form
• Type 1 diabetes for at least 10 years followed at Caen University Hospital, equipped with a continous glucose monitoring system

Exclusion Criteria:

• Trained athletes (≥ 6 hours of sustained physical exercise >70% VO2max per week for > 6 months)
• Chronic cardiovascular disease or cardiovascular treatment
• Personal history of chemotherapy and/or thoracic radiotherapy
• Cerebral and/or spinal disease
• Inclusion of the subject in another biomedical research protocol of interventional type (during the study or in the 3 months prior to inclusion)
• Pregnant, breast-feeding or parturient women
• Adults under legal protection (guardianship, curators) or unable to express their consent or deprived of their freedom

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: T1 Diabetic group; Group with diabetic patients	Other: Cardiovascular and Baroreflex stimulation by Tilting; Tilt of the patient at 4 angles (22°, 42°, 58° and 80°), the order is randomized for 3 angles (22°, 42°, 58°) while 80° will always be last.; Other Names: Tilt; Other: Cardiovascular and Baroreflex stimulation by Lower Body Negative Pressure; The patient will undergo 4 level of LBNP (10Torr, 20Torr, 35Torr, 50Torr), the order is randomized for 3 intensities (10Torr, 20Torr, 35Torr) while 50Torr will always be last.; Other Names: LBNP
Other: Healthy Control Group; Control group with healthy participants	Other: Cardiovascular and Baroreflex stimulation by Tilting; Tilt of the patient at 4 angles (22°, 42°, 58° and 80°), the order is randomized for 3 angles (22°, 42°, 58°) while 80° will always be last.; Other Names: Tilt; Other: Cardiovascular and Baroreflex stimulation by Lower Body Negative Pressure; The patient will undergo 4 level of LBNP (10Torr, 20Torr, 35Torr, 50Torr), the order is randomized for 3 intensities (10Torr, 20Torr, 35Torr) while 50Torr will always be last.; Other Names: LBNP

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Heart rythme	continuous electrocardiogram monitoring for assessing the variation of heart frequency	baseline, during the intervention
Arterial blood pressure	continuous central arterial pressure monitoring using Finapress	baseline, during the intervention
thoracic Impedancemetry	estimation of body fluid variation as a surrogate of prelaod	baseline, during the intervention
Echocardiography	non invasive diastolic intraventricular pressure gradient	baseline, during the intervention

Collaborators and Investigators

• Sponsor: University Hospital, Caen
• Collaborators: Jozef Stefan Institute; INSERM UMR-S 1075 COMETE, Caen, France; CNRS UMR 5220 INSERM U1294 CREATIS ,Université Lyon 1, INSA Lyon, France

Study record dates

Study Major Dates

• Study Start (Actual): November 22, 2023
• Primary Completion (Estimated): June 22, 2025
• Study Completion (Estimated): October 15, 2025

Study Registration Dates

• First Submitted: November 23, 2023
• First Submitted That Met QC Criteria: December 19, 2023
• First Posted (Actual): January 5, 2024

Study Record Updates

• Last Update Posted (Actual): March 26, 2025
• Last Update Submitted That Met QC Criteria: March 24, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: Diabetes; Echocardiography; Cardiac function; Gravity; Tilt-test; Intracardiac pressure gradients; Lower Body Negative Pressure; Color Doppler M mode
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Autoimmune Diseases; Immune System Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Diabetes Mellitus, Type 1
• Other Study ID Numbers: 23-0077

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No