The objective of this study, led by German scientists, was to determine the prevalence and extent of cardiac abnormalities in patients who were referred for cardiac magnetic resonance imaging (MRI) due to clinical signs of post-acute sequelae of SARS-CoV-2 infection (PASC)/ long COVID. Cardiac MRI revealed signs of non-ischemic myocardial fibrosis in 30% of PASC/long COVID patients, exceeding the prevalence of this disease in the normal adult population.
The current reports regarding the prevalence of cardiovascular symptoms in patients with PASC vary widely. There are several possible explanations for this, including inconsistent inclusion criteria and varying definitions of acute myocardial inflammation. The Society for Cardiovascular MRI has proposed optimized cardiac MRI protocols for scanning patients in the active or convalescent phase of COVID-19 infection.
About the study
The goal of this two-center retrospective study was to determine the presence and extent of cardiac abnormalities in patients exhibiting clinical manifestations of PASC. Two hospitals retrospectively identified all patients who were referred for cardiac MRI within a two-year period due to clinical signs of PASC. The clinical manifestations of PASC included fatigue, an exertional dyspnea, exercise intolerance, tachycardia/palpitations, and chest pain more than 4 weeks after infection. The most common symptoms were an exertional dyspnea (23%) and tachycardia/palpitations (22%).
A total of 129 patients were included (51% were female, mean age was 41 years). The median (IQR) interval between cardiac MRI and a positive reverse-transcription polymerase chain reaction test was 4 months.
Volumetric analysis revealed an abnormal (<55%) ejection fraction in 21% of PASC patients, and left ventricular dilation (end-diastolic volume index ≥ 100 mL/m2) in 19% of PASC patients. The pericardial effusion (>5 mm) was observed in 14% of patients, whereas the pleural effusion (>20 mm) was observed in 5% of patients. The focal late gadolinium enhancement was observed in 38% of patients, predominantly in the subepicardial layer. None of the late gadolinium enhancement lesions showed corresponding visual or quantitative myocardial edema.
Further mapping analyses revealed that 14% of patients had abnormal myocardial T1 relaxation times, while only 2% of patients had abnormal T2 relaxation times. There was no case of active myocarditis or an acute myocardial infarction.
Cardiac MRI revealed with normal cardiac results in the majority of PASC patients (57%). However, a significant portion of the cohort (30%) showed signs of non-ischemic myocardial fibrosis, exceeding the prevalence of this disease in the normal adult population. In addition, cardiac abnormalities like post-ischemic fibrosis (4%) and structural heart disease (9%) were found. 8% of patients with normal cardiac results had suspected pulmonary abnormalities (pulmonary fibrosis/atelectasis).
The researchers emphasized that their study focused only on patients who were referred for cardiac MRI, and strictly relied on established international guidelines for the detection of myocardial inflammation.
The most significant finding of this study revealed signs of non-ischemic myocardial fibrosis in nearly a third (30%) of PASC/long COVID patients. This prevalence is particularly concerning as it exceeds the prevalence of this disease in the normal adult population. Furthermore, this suggests that a history of myocarditis might be the reason for the persistent symptoms in patients with PASC/long COVID.
According to the authors, there is no evidence of a causal correlation between SARS-CoV-2 infection and their findings. However, this study emphasizes the importance of cardiac MRI in the evaluation of PASC/long COVID patients with cardiovascular symptoms.
This article was published in Diagnostics.
Halfmann MC. et al. Cardiac MRI Findings in Patients Clinically Referred for Evaluation of Post-Acute Sequelae of SARS-CoV-2 Infection. Diagnostics 2023, 13, 2172. (Open Access)