Is Post-exertional Symptom Exacerbation Specific to Patients With Myalgic Encephalomyelitis / Chronic Fatigue Syndrome? A Study Comparing Patients With Myalgic Encephalomyelitis / Chronic Fatigue Syndrome and Patients With Cardiac Diseases Who Underwent an Exercise Test.

Myalgic Encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) is a disease characterized by persistent and unexplained fatigue associated with diffuse pain, sleep disorders, neurocognitive and autonomic symptoms, musculoskeletal manifestations and digestive symptoms. A central feature of this disease is post-exertional symptom exacerbation, also referred to as post-exertional malaise, defined as the worsening or the appearance of symptoms after physical or mental exertion, sometimes even minimal. Several studies have described post-exertional malaise in populations of patients with ME/CFS following a standardized exercise test performed over one or two consecutive days. These studies confirmed the presence of post-exertional malaise in ME/CFS patients compared with healthy controls or patients with multiple sclerosis. However, no data are available evaluating the impact of an exercise test on symptoms in patients referred to cardiology for this examination. Patients with cardiac diseases may also present symptoms such as fatigue, dyspnea or exercise intolerance. This study aims to compare post-exertional symptoms in two populations: patients with ME/CFS and patients with cardiac diseases undergoing an exercise test as part of routine clinical evaluation. The study also aims to measure variations in muscle oxyhemoglobin and deoxyhemoglobin concentrations before, during and after exercise using Near Infrared Spectroscopy (NIRS).