Muscle Function in Patients With Single-chamber Heart

NCT07420660 | Not Yet Recruiting

• 1 other identifier: 2024-07444-01
• Study Type: observational
• Target: 40
• Locations: 0 countries
• Sites: N/A

Brief Summary

Groundbreaking cardiac surgery has significantly improved survival rates for patients with single-chamber hearts. However, despite these life-saving interventions, the long-term prognosis remains concerning, with an increased risk of heart failure, sudden cardiac death, and reduced quality of life. The absence of a chamber that pumps blood to the lungs means individuals must rely on their leg muscles to passively return blood and oxygenate the lungs. Unfortunately, studies indicate reduced muscle mass and function in these patients. The aim is to clarify the complex interplay between single-chamber circulation and muscle function, paving the way for targeted interventions such as muscle strengthening training for this unique patient group. Our hypothesis is that muscle mass and function correlate with circulatory limitations, and that muscle strengthening training could, over time, improve both muscle and circulatory function simultaneously. The first part of the project includes tests for maximal oxygen uptake, heart and circulatory function, muscle strength, muscle mass/body composition, and quality of life in adult patients (aged 16 and over) with single-chamber hearts. The study may ultimately lead to improved interventions and exercise recommendations that promote an active lifestyle and enhance health, circulation, and physical function in patients with single-chamber hearts.

Conditions

Fontan Circulation

Keywords

Skeletal muscle; Fontan patients; Congenital heart disease; muscle function

Outcome Measures

Primary Outcomes (2)

• Relationship between anterior thigh muscle volume and peak maximal oxygen uptake in patients vs. controls

  Muscle volume is measured in litres using magnetic resonance imaging. VO2peak is measured in L/min and ml/kg/min using cardiopulmonary exercise testing with breath-by-breath gas analyzers.

  Baseline visit (single time-point)

• Relationship between knee extension muscle strength and peak maximal oxygen uptake in patients vs. controls

  Muscle strength (isometric peak torque) is measured in Nm using Biodex. VO2peak is measured in L/min and ml/kg/min using cardiopulmonary exercise testing with breath-by-breath gas analyzers.

  Baseline visit (single time-point)

Secondary Outcomes (5)

• Anterior thigh muscle fat infiltration in patients vs. controls

  Baseline visit (single time-point).

• Whole body muscle composition in patients vs. controls

  Baseline visit (single time-point)

• Quality of life in patients vs. controls and its relationship to muscle function

  Baseline visit (single time-point visit)

• Cardiac function in patients vs. controls

  Baseline visit (single time-point)

• Whole body fat composition in patients vs. controls

  Baseline visit (single time-point)

Study Arms (2)

Patients

Controls

Eligibility Criteria

• Age: 16 Years - 50 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Patients linked to the Region Stockholm outpatient clinic

You may qualify if:

• Diagnosis of a Fontan circulation: individuals who have undergone the Fontan procedure with only one functioning systemic ventricle, confirmed by medical records or attending physician.
• Stable clinical status: patients should be clinically stable without significant cardiovascular or renal dysfunction as determined by clinical examinations.
• Age range: 16-50 years.
• Ability to exercise: Participants must be physically able to participate in the exercise protocol according to a preliminary medical examination.
• Controls: Age and sex-matched. Healthy (no chronic diseases, assessed by health questionnaire and interview).

You may not qualify if:

• Severe functional limitations: Patients with clear functional limitations unrelated to Fontan physiology, such as musculoskeletal disorders.
• Significant comorbidities: Serious non-cardiac comorbidities that may independently affect work capacity, such as advanced pulmonary disease.
• Contraindications for exercise testing: Conditions that contraindicate physical testing, such as uncontrolled cardiac arrhythmias or severe heart failure (New York Heart Association III-IV).

Sponsors & Collaborators

• Karolinska Institutet: lead

MeSH Terms

Conditions

Heart Defects, Congenital

Condition Hierarchy (Ancestors)

Cardiovascular Abnormalities; Cardiovascular Diseases; Heart Diseases; Congenital Abnormalities; Congenital, Hereditary, and Neonatal Diseases and Abnormalities

Central Study Contacts

Tommy Lundberg, PhD

CONTACT

+46738352974; tommy.lundberg@ki.se

Andrea Tryfonos, PhD

CONTACT

andrea.tryfonos@ki.se

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Docent in physiology

Study Record Dates

• First Submitted: January 28, 2026
• First Posted: February 19, 2026
• Study Start: February 18, 2026
• Primary Completion (Estimated): May 31, 2026
• Study Completion (Estimated): May 31, 2026
• Last Updated: February 19, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share