Evaluation of Myocardial Function by Global Longitudinal Strain (GLS) Measurement in 2D Echocardiography of Patients With Fibromyalgia

Fibromyalgia (FM) is a chronic pain syndrome that affects multiple body systems and is often associated with fatigue, sleep disturbances, anxiety, and other comorbidities. Increasing evidence suggests that FM is also linked to cardiovascular dysfunction due to autonomic imbalance, sympathetic overactivity, and endothelial dysfunction. Patients with FM may therefore be at higher risk of developing subclinical ventricular dysfunction even before overt cardiovascular disease becomes apparent. Traditional echocardiographic evaluation of left ventricular function is based on ejection fraction (LVEF). However, LVEF has important limitations. It may remain normal despite underlying myocardial impairment, is strongly influenced by loading conditions, and often fails to detect early myocardial dysfunction. Recent advances in echocardiography allow for the assessment of Global Longitudinal Strain (GLS), a sensitive and reproducible measure of myocardial deformation. GLS abnormalities can be detected earlier than changes in LVEF and are predictive of future declines in ejection fraction. This study aims to evaluate myocardial function in fibromyalgia patients using GLS obtained by two-dimensional speckle-tracking echocardiography (2D-STE). By comparing FM patients with age- and sex-matched healthy controls, the study seeks to determine whether FM patients show a higher prevalence of subclinical ventricular dysfunction. The study is designed as a prospective, observational, case-control study. A total of 118 participants will be enrolled: 59 patients diagnosed with fibromyalgia according to the 2010 American College of Rheumatology (ACR) criteria, and 59 control subjects without fibromyalgia. The control group will consist of volunteers presenting with mechanical low back pain but without systemic rheumatic disease. All participants will undergo echocardiographic examination using a standardized protocol with Vivid E95 Dimension ultrasound equipment (GE Healthcare). Global