Skip to main content
OpenTrials
Not Yet Recruiting

NCT Number: NCT07420660

Muscle Function in Patients With Single-chamber Heart

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.

Not Yet Recruiting

Trial opening soon.

Get Notified

Key information

Conditions

Fontan Circulation Cardiovascular Abnormalities Cardiovascular Diseases Congenital Abnormalities Congenital, Hereditary, and Neonatal Diseases and Abnormalities Heart Defects, Congenital Heart Diseases

Age range

16 year–50 year

Sex eligibility

All sexes

Study type

Observational

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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).

Exclusion criteria

  • Recent surgery or hospitalization: individuals who have undergone cardiovascular surgery or hospitalization within six months prior to inclusion.
  • 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).

Treatment and study plan

Primary outcomes

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

    Time frame: Baseline visit (single time-point)

    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.

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

    Time frame: Baseline visit (single time-point)

    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.

Secondary outcomes

  1. Anterior thigh muscle fat infiltration in patients vs. controls

    Time frame: Baseline visit (single time-point).

    Measured in % using magnetic resonance imaging.

  2. Whole body muscle composition in patients vs. controls

    Time frame: Baseline visit (single time-point)

    Measured in L and/or per kg body mass using magnetic resonance imaging

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

    Time frame: Baseline visit (single time-point visit)

    Quality of life aspects are measured using surveys (SF-36).

  4. Cardiac function in patients vs. controls

    Time frame: Baseline visit (single time-point)

    Ventricular end-diastolic volume, Ventricular end-systolic volume, and Stroke volume measured in ml/m²

  5. Whole body fat composition in patients vs. controls

    Time frame: Baseline visit (single time-point)

    Measured in L and/or per kg body mass using magnetic resonance imaging

Study contacts

Contact information is provided by the study sponsor or research team.

Andrea Tryfonos, PhD

CONTACT

[email protected]

Tommy Lundberg, PhD

CONTACT

[email protected]

+46738352974

Sponsors and collaborators

Lead sponsor

Karolinska Institutet

Other

Registry information

Official study title

Importance of Muscle Function for Patients With Single-chamber Heart

Acronym: Muscle in TCPC

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Feb 19, 2026
Registry last updated
Feb 19, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.