Diffuse Myocardial Inflammation in COVID-19 Associated Myocarditis Detected by Multiparametric Cardiac Magnetic Resonance Imaging

Abstract

A 79-year-old male was hospitalized due to fatigue, shortness of breath, and recurrent syncopes.He denied symptoms of fever or pain.He had a previous history of asthma.No history of cardiovascular disease was reported, and previous cardiac check-ups were unremarkable (last described left ventricular ejection fraction was 65%).Initial physical examination in the emergency department revealed heart rate of 75 bpm, blood pressure of 101/64 mm Hg, body temperature of 35.6°C, oxygen saturation of 94%, and moderate wheezing on auscultation.On initial blood test, CRP (C-reactive protein) was measured at 13.80 mg/L and high sensitive troponin T at 18.8 ng/L, but leucocyte blood count and NT-proBNP (N-terminal prohormone of brain natriuretic peptide) were normal.Electrocardiogram, chest x-ray, and echocardiography were normal.Patient was referred for contrast-enhanced computed tomography to rule out pneumonia or pulmonary embolism that revealed pulmonary ground-glass peripheral infiltrates in the left upper lobe and discrete pleural and pericardial effusions (Figure 1).Because of the outbreak of coronavirus disease 2019 (COVID-19), a nasopharyngeal swab was performed at admission, real-time reverse transcriptasepolymerase chain reaction assay returned positive for severe acute respiratory syndrome coronavirus 2. Due to respiratory and hemodynamic worsening, the patient was moved to the intensive care unit.Blood tests showed an increase in CRP (64.23 mg/L), leucocyte blood count (14.60 g/L), troponin T (63.5 ng/L), and NT-proBNP (1178.0pg/mL).Cardiac magnetic resonance (CMR) was performed at 1.5 T at day 10 after admission (Figure 2).CMR analysis showed normal left ventricular size (left ventricular end-diastolic volume index: 68 mL/ m 2 ; left ventricular mass index 42 g/m 2 ) and mild systolic dysfunction (left ventricular ejection fraction: 49%) with discrete global hypokinesis, and normal right ventricular volume and function (Movies I and II in the Data Supplement).Pericardial effusion was confirmed, localized mainly around the left ventricular lateral wall (≈10 mm).T2-weighted short TI inversion recovery sequences displayed diffuse interstitial myocardial edema with an increased T2 signal intensity ratio.Presence of diffuse myocardial inflammation was confirmed by T2 mapping (global T2 relaxation times: 62 ms; center-specific cutoff value for acute myocarditis: ≥55.9 ms; global myocardial T2 relaxation time represents a mean value of all 16 heart segments). 1Late-gadolinium enhancement imaging (inversion time by using the Look-Locker technique: 240 ms) was negative for focal myocardial lesions, but prolonged T1 relaxation times could be measured (global T1 relaxation times: 1035 ms; center-specific cutoff value for acute myocarditis: ≥1000 ms; global myocardial T1 relaxation time represents a mean value of all 16 heart segments). 1CMR parameters fulfilled the revised 2018 Lake Louise criteria for the diagnosis of myocarditis. 2Medical treatment