Preload failure
Preload failure or PLF occurs when the maximal exercise-induced cardiac output (CO) is decreased without an accompanying increase in right heart or pulmonary vascular pressures.[citation needed]
In cardiac physiology, preload is the end diastolic volume that stretches the right or left ventricle of the heart to its greatest dimensions under variable physiologic demand.[citation needed] It is defined as the length of the heart muscle just before it starts to pump and is measured clinically by the volume of blood in the left ventricle, the main pumping chamber, when it is most relaxed.[citation needed]
Preload can be influenced by blood volume, heart rhythm, left ventricular relaxation, and alterations in afterload.[citation needed]
ME/CFS[edit | edit source]
Preload failure is associated with exercise intolerance in myalgic encephalomyelitis/chronic fatigue syndrome, orthostatic hypotension, and postural orthostatic tachycardia.[1]
Treatments[edit | edit source]
David Systrom at Brigham Women's Hospital in Boston is currently conducting phase III trials of Mestinon in patients with preload failure.[2] Pyridostigmine (the generic name for Mestinon) has been investigated previously.[1]
Notable studies and publications[edit | edit source]
- Pyridostigmine for Exercise Intolerance Treatment in Preload Failure[1] - Meeting abstract)
See also[edit | edit source]
- Pyridostigmine
- Mestinon
- Invasive cardiopulmonary exercise test (iCPET)
- Post-exertional malaise
- Exercise intolerance
Learn more[edit | edit source]
- 2018, Advancements in ME/CFS Research, David M. Systrom, MD; Brigham and Women's Hospital | ME/CFSAlert 98 (Interview)
References[edit | edit source]
- ↑ 1.0 1.1 1.2 Oliveira, Rudolf K.; Tracy, Julie A.; Karin, Abbey L.; Waxman, Aaron; Systrom, David (May 1, 2016). "Pyridostigmine for Exercise Intolerance Treatment in Preload Failure". American Thoracic Society International Conference Abstracts. American Thoracic Society. pp. A5664–A5664. doi:10.1164/ajrccm-conference.2016.193.1_meetingabstracts.a5664.
- ↑ "The Exercise Response to Pharmacologic Cholinergic Stimulation in Preload Failure - ClinicalTrials.gov". clinicaltrials.gov. Retrieved April 8, 2019.
