P868Neutrophil-to-lymphocyte ratio at the onset of acute myocarditis reflects the extent of myocardial necrosis

Background: Acute myocarditis is an inflammatory process often in the context of a viral infection. At myocardial level, the extent of inflammation and necrosis is heterogeneous and strongly influences the prognosis. However, bedside markers of myocardial alterations during the acute phase of myocarditis are lacking, and the role of neutrophil-to-lymphocyte ratio (NLR) has never been tested. NLR has already proven its prognostic value in various cardiovascular diseases, infections, and inflammatory diseases. Purpose: To correlate NLR to the extent of myocardial inflammation detected by Cardiovascular Magnetic Resonance (CMR) in the setting of acute myocarditis. Methods: Patients diagnosed with acute myocarditis based on the clinical presentation and confirmed by CMR (presence of at least 2 Lake Louise criteria) were prospectively enrolled. Subjects with evidence of chronic myocardial inflammation were excluded. Demographics, clinical and routine blood samples data were collected through chart review. The absolute neutrophil count was divided by the absolute lymphocyte count to calculate the NLR. CMR images were reviewed and analysed by a blinded certified reader. Cardiac chamber volumes and function, as well as the amount of left ventricular myocardial necrosis, were quantified.