Abstract and Introduction
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a medically unexplained illness characterized by severe fatigue limiting normal daily activities for at least 6 months accompanied by problems with unrefreshing sleep, exacerbation of symptoms following physical or mental efforts (postexertional malaise [PEM]), and either cognitive reports or physiological evidence of orthostatic intolerance in the form of either orthostatic tachycardia and/or hypocapnia. Although rarely considered to have cardiac dysfunction, ME/CFS patients frequently have reduced stroke volume with a significant inverse relation between cardiac output and PEM severity. Magnetic resonance imaging of ME/CFS patients compared with normal control subjects found significantly reduced stroke, end-systolic, and end-diastolic volumes together with reduced end-diastolic wall mass. Another cardiovascular abnormality is reduced nocturnal blood pressure assessed by 24-hour monitoring. Autonomic dysfunction is also frequently observed with postural orthostatic tachycardia and/or hypocapnia. Two consecutive cardiopulmonary stress tests may provide metabolic data substantiating PEM.
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a medically unexplained illness characterized by severe fatigue limiting normal daily activities among other symptoms. Fatigue is the quintessential symptom for diagnosis, which may have many etiologies ranging from neuromuscular to psychiatric, infectious, endocrine, and/or cardiac causes. A frequent surrogate for fatigue is a reduction in functional capacity, which is predominantly determined by cardiovascular response to a maximal exercise demand. In this review, we will describe cardiac abnormalities that occur in ME/CFS patients and whether these cardiovascular factors contribute to this syndrome. We will review the evidence that central cardiac changes occur in these patients, including reduced cardiac output and peripheral changes such as autonomic dysfunction and/or muscular disease.
J Am Coll Cardiol. 2021;78(10):1056-1067. © 2021 American College of Cardiology Foundation