In a study just published in the Journal of Infectious Diseases, a team of researchers from UC San Francisco found that long-term COVID patients often had lower-than-expected exercise capacity, with chronotropic incompetence (inadequate increase in heart rate during exercise) being the main reason. reason. Additionally, they found an association between reduced exercise capacity and early post-Covid elevations in inflammatory biomarkers. In addition, they found that a slowed heart rate during exercise may be linked to the Epstein-Barr virus (EBV).
First author Matthew DurstenfeldMD, MAS, designed the cardiovascular substudy as part of the Long-Term Effects of Novel Coronavirus Infection (LIINC) study led by Michael Peluso, MD, MHS, assistant professor of medicine at UCSF. The LIINC is designed to assess physical and mental health after exposure to COVID-19 by including individuals representing all acute illnesses and post-acute recovery. The study began in November 2020 using echocardiograms to assess heart conditions underlying COVID symptoms.
When the initial ultrasound-based study failed to reveal the mechanisms of cardiac symptoms, the team changed the study protocol to conduct a second visit with study participants a year later for advanced tests, including cardiopulmonary exercise testing (CPET), cardiac magnetic resonance imaging (CMR). ) and ambulatory heart rhythm monitoring. Blood samples were also collected from the participants in the sub-study, which were processed for serum and plasma during echocardiographic visits.
Sixty participants, with a median age of 53, were studied about a year and a half after their COVID infection. In the CPET study, 49% of those with symptoms had reduced exercise capacity compared to 16% without symptoms. Adjusted VO2 peak (the amount of oxygen the body uses during exercise) was 16.9 percent lower than predicted among those with symptoms. Chronotropic incompetence was a common finding, and inflammatory biomarkers and antibody levels in the first months after COVID-19 were negatively correlated with VO2 peaks more than a year later.
“The results suggest that chronotropic incompetence—failure to reach 80% of expected maximum heart rate during exercise—contributes to exercise limitations in chronic COVID,” said Durstenfeld, a cardiologist and assistant professor of medicine at UCSF. “We also found evidence of EBV reactivation in all subjects with chronotropic incompetence, but no evidence of myocarditis, cardiac dysfunction, or clinically significant arrhythmias.”
The authors note the clinical diagnostic challenge presented in symptomatic patients when objective findings of cardiac dysfunction are absent on multimodal cardiopulmonary testing. They suggest that clinical translational and evidence-based research to characterize the various phenotypes and mechanisms of acute COVID symptoms is urgently needed to identify potential therapies.
Until additional treatments are available, the authors believe that individuals living with impaired exercise capacity may benefit from exercise to improve their symptoms. Patient advocates have raised important concerns about the safety of exercise in those with overlap myalgic encephalitis/chronic fatigue syndrome.
“Although exercise is unlikely to cure long-term COVID, preliminary data suggest that exercise is the only intervention that has been shown to improve exercise capacity, symptoms and quality of life,” Durstenfeld said. “Because patients are concerned that exercise may make some people’s symptoms worse, we need to carefully study the role of exercise in Long COVID.”
Source: The Nordic Page