In the wake of the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a significant number of individuals have experienced persistent symptoms beyond the acute phase of the illness.
This condition, known as post-acute sequelae of SARS-CoV-2 infection (PASC) or long COVID, has raised concerns about potential long-term health consequences, including cardiovascular involvement. Cardiac magnetic resonance imaging (MRI) has emerged as a valuable tool for evaluating cardiac abnormalities in patients with suspected PASC.
This article aims to delve into a study that investigated cardiac MRI findings in a pre-selected cohort of patients with clinical suspicion of PASC.
Study Design and Objectives
The study focused on a pre-selected cohort of patients referred for cardiac MRI due to clinical suspicion of PASC. The primary objective was to assess the prevalence and types of cardiac abnormalities observed in this cohort. To enhance the generalizability of the results and mimic real-world clinical practice, the study strictly adhered to established international guidelines for the detection of myocardial inflammation.
Cardiac MRI Findings
The study findings revealed several notable cardiac MRI findings in the pre-selected cohort of patients with suspected PASC. Among the patients, 30% exhibited signs of post-inflammatory myocardial fibrosis, which could potentially indicate a history of myocarditis.
Importantly, no cases of active myocarditis or acute myocardial infarction were identified. However, in 4% of patients, post-ischemic myocardial findings were observed, suggesting the presence of pre-existing ischemic heart disease.
Additionally, previously unknown structural cardiac abnormalities were diagnosed in 9% of patients.
Comparison with Previous Studies
The prevalence of abnormal cardiac MRI findings in patients after SARS-CoV-2 infection has been reported to vary widely in previous studies, ranging from 26% to 78%. However, these variations can be attributed to differences in study design and inclusion criteria.
In contrast, the current study focused exclusively on clinical referrals for cardiac MRI and relied on established international guidelines for the detection of myocardial inflammation. This approach aimed to improve generalizability and closely resemble real-world scenarios in imaging departments when evaluating PASC-associated cardiovascular disease.
The study reported a higher prevalence (30%) of non-ischemic myocardial fibrosis compared to the general adult population, where rates of approximately 7.9% have been reported.
However, unlike previous clinical studies, the current investigation did not identify cases of active myocardial inflammation, which aligns with findings from a meta-analysis of autopsy results demonstrating rare histopathological evidence of active myocarditis (<2%).
Methodological Considerations and Limitations
It is essential to acknowledge the limitations of the current study. Its retrospective design and the absence of baseline studies before COVID-19 restrict the ability to establish a causal relationship between SARS-CoV-2 infection and structural, ischemic, or post-inflammatory cardiac findings. Some cardiac abnormalities, such as dilated cardiomyopathy, could also represent pre-existing subclinical diseases that manifested overtly in the context of PASC.
Furthermore, the study did not include blind inter- and intra-reader variability assessments, which could have provided additional insights into the consistency of the findings. However, considering that the study primarily focused on qualitative assessment of cardiac abnormalities, the value of additional quantitative measurements would likely be limited.
The investigation of cardiac MRI findings in a pre-selected cohort of patients referred for imaging due to clinical suspicion of PASC revealed significant insights into the cardiac manifestations associated with post-acute sequelae of SARS-CoV-2 infection. The study demonstrated a relatively high prevalence of non-ischemic myocardial fibrosis and identified previously unknown structural cardiac abnormalities.
However, no active myocarditis or acute myocardial infarction cases were detected. The findings underscore the importance of cardiac evaluation in patients with suspected PASC and emphasize the need for further research to establish causal relationships and better understand the long-term cardiac implications of SARS-CoV-2 infection.