Background About 47.3 million people have recovered from coronavirus disease 2019 (COVID-19). Manifestations of cardiac involvement have been noted in a significant number of patients in the acute phase. There are increasing concerns that some of these cardiac sequels may persist beyond the acute phase. If untreated, the sustained cardiac injury, especially myocarditis and fibrosis, could have severe consequences. Recent studies have assessed the presence of cardiac involvement using cardiac magnetic resonance (CMR) imaging during the post-acute phase. Purpose We present a systematic review of studies assessing evidence of cardiac involvement in patients recovered from COVID-19 during the post-acute phase using Cardiac Magnetic Resonance (CMR) Imaging. Methods We reported this study in accordance with PRISMA. A systematic search was performed on PubMed, Embase (Elsevier), and Google scholar databases using Boolean operators and the relevant key terms covering COVID-19, Cardiac injury, CMR, and follow-up. Retrieved articles were included based on predefined eligibility criteria. Results Of 1406 articles retrieved from the initial search, 11 items, 9 cohort, and 2 case series studies met our eligibility criteria. The rate of raised T1 (reported in 6 articles) in patients recovered from COVID-19 varied across studies from 5% to73%. In 4 out of 9 studies, raised T2 was detected in any patients, and in remained studies, its rate ranged from 2% to 60%. In most of the included studies, LGE (myocardial or pericardial) was observed in COVID-19 survivors, ranged from 7.0% to 100%. Myocardial LGE mainly had nonischemic patterns. None of the cohort studies observed myocardial LGE in “healthy” controls. Most studies found that patients who recovered from COVID-19 had significantly a greater mean (SD) T1 and T2 compared to participants in the control group. Conclusion Our systematic review study found evidence of subclinical and clinical myocardial and pericardial involvement in patients recovered from COVID-19. FUNDunding Acknowledgement Type of funding sources: None.

Background Myocarditis following COVID-19 vaccination is a rare adverse event that was recently reported. Understanding the pattern and severity of myocardial injury in myocarditis caused by COVID-19 vaccination is imperative for improving care of the patients. Purpose To detect the pattern and severity of myocardial injury in patients with myocarditis following COVID-19 vaccination based on cardiac MRI findings. Study type Systematic review. Method Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we systematically reviewed the literature by screening 2404 databases using boolean operators and the relevant key terms covering COVID-19 vaccine, myocarditis, and Cardiac MRI. We included all observational MRI studies on patients with suspected myocarditis following COVID-19 vaccination. Cardiac MRI findings, including T1, T2, ECV, LGE, and left ventricular ejection fraction, were extracted from included studies. Statistical tests As a single case series, individual-level patient data (IPD) studies were pooled with aggregated–level data (AD) studies through two-stage analyses. For this purpose, first, data from all case series and case reports with IPD were aggregated using one-stage IPD analyses. Results Based on our two-stage pooled analyses of IPD and AD studies, diagnosis of myocarditis using lake luoise criteria was confirmed in 74% (95% confidence interval (CI): 49% to 94%) of patients. Cardiac MRI abnormalities included elevated T2 in 67% (95% CI: 45% to 87%), myocardial LGE in 91% (95% CI: 81% to 99%) [having a subepicardial/midwall pattern: 99.5%], impaired LVEF (<50%) in 4% (95% CI: 0.0% to 9.0%). Also, elevated T1 and ECV (>30), reported only by some IPD studies, was detected in 72.5% (66/91) and 32% (16/50) of patients, respectively. Data conclusion Myocardial injury in COVID-19 vaccine-associated myocarditis may have a similar pattern compared to other forms of acute myocarditis. Despite other myocarditis, Preserved LVEF is a common finding in these patients. Funding Acknowledgement Type of funding sources: None.