Characterization of Obesity-related Cardiomyopathy Through Exploration of Human Atrial Trabeculae Contraction

Study Overview
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Brief Summary
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The investigators aim to explore obese cardiomyopathy by studying contractile twitch force, sarcomere sensitivity to calcium and mitochondrial function in atrial myocardial samples of patients grouped according to their body mass index, i.e. normal weight, overweight and obese.

Detailed Description
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Obesity is associated with the development of heart failure, regardless of coronary artery disease or other comorbidities. Right atrial samples obtained from patients undergoing cardiac surgery and presenting no sign of clinical cardiomyopathy will be grouped according to patient's body mass index. Atrial trabeculae will be explored to dissect out the respective contribution of (i) sarcoplasmic reticulum dysfunction (isometric twitch force contraction analysis), (ii) abnormal sarcomere sensitivity to calcium assessed in permeabilized fibers and (iii) mitochondrial dysfunction to intrinsec contractile dysfunction of myocardium in obese patients.

Official Title
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Characterization of Obesity-related Cardiomyopathy Through Exploration of Human Atrial Trabeculae Contraction

Conditions
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Obesity, Heart Failure

Intervention / Treatment
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* Other: functional tissu atrial analysis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patient schedulled for coronary artery bypass graft surgery or aortic valve replacement surgery with extracorporeal circulation must be over 18 years of age must be able to read and understand the consent form in French must be in sinus rhythm at inclusion time Exclusion Criteria: medical history of type 1 diabetes medical history of sustained atrial arrhythmia pregnancy class III anti-arhythmic drug

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| obese patients<br>patients with BMI > 30 | Other: functional tissu atrial analysis<br> <br> |
| no obese patients<br>norma weight patient (BMI<25) overweight patients ( 25< BMI >30) | Other: functional tissu atrial analysis<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intrinsic myocardial contractile force | twitch force developed by atrial trabeculae assessed in isometric conditions in atrial samples | the day of cardiac surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| sarcomere sensitivity to calcium | force-calcium concentration relation assessed on permeabilized atrial fibers | the day of cardiac surgery | 
| Mitochondrial function | assesment of mitochondrial respiration and calcium retention capacity by oxygraphic measurement in saponin-permeabilized atrial fibers | the day of cardiac surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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obese cardiomyopathy, mitochondria, contractile dysfunction