Abstract
COVID-19 infection is associated with myocarditis, and cardiovascular magnetic resonance (CMR) is the reference non-invasive imaging modality for myocardial tissue characterization. Quantitative CMR techniques, such as feature tracking (FT) and left ventricular global longitudinal strain (GLS) analysis, have been introduced as promising diagnostic tools to improve the diagnostic accuracy of suspected myocarditis. The aim of this study was to analyze the left ventricular global longitudinal strain (GLS) and the influence of T1 and T2 relaxation times, ECV, and LGE appearance on GLS parameters in a multiparametric imaging protocol in patients who recovered from COVID-19. The 86 consecutive patients enrolled in the study had all recovered from mild or moderate COVID-19 infections; none required hospitalization. Their persistent symptoms and suspected myocarditis led to cardiac magnetic resonance imaging within 3 months of the diagnosis of the SARS-CoV-2 infection. Results: Patients with GLS less negative than -15% had significantly lower LVEF (53.6% ± 8.9 vs. 61.6% ± 4.8; <0.001) and were significantly more likely to have prolonged T1 (28.6% vs. 7.5%; p = 0.019). Left ventricular GLS correlated significantly with T1 (r = 0.303; p = 0.006) and LVEF (r = -0.732; p < 0.001). Left ventricular GLS less negative than -15% was 7.5 times more likely in patients with prolonged T1 (HR 7.62; 95% CI 1.25-46.64). The reduced basal inferolateral longitudinal strain had a significant impact on the global left ventricular longitudinal strain. ROC results suggested that a GLS of 14.5% predicted prolonged T1 relaxation time with the best sensitivity and specificity. Conclusions: CMR abnormalities, including a myocarditis pattern, are common in patients who have recovered from COVID-19. The CMR feature-tracking left ventricular GLS is related to T1 relaxation time and may serve as a novel parameter to detect global and regional myocardial injury and dysfunction in patients with suspected myocardial involvement after recovery from COVID-19.