Characteristics and prognosis of patients hospitalized for acute myocarditis

Abstract

Few data are available on the outcome and prognostic factors in acute myocarditis (AM) diagnosed by CMR. We aimed to determine the characteristics and identify the factors associated with in-hospital and 5-year prognosis in patients hospitalized at Amiens University Hospital for AM between 2010 and 2020. 185 patients hospitalized with an initial CMR-based diagnosis of AM were enrolled between January 2010 and June 2020. Analysis of clinical, biological, and imaging data were performed to identify predictors of in-hospital and long term outcomes. Mean age was 33 years old with 80% of men. Men were significantly younger than women ( P < 0.001). The most frequent symptom at presentation was chest pain (92% of patients). Mean Left Ventricular Ejection Fraction (LVEF) measured by CMR at admission was 55% and left ventricular dysfunction was present in 24% of patients at baseline (LVEF < 50%). A total of 27 patients (14.6%) presented at least one event during hospitalization. On multivariable regression analysis, only the absence of chest pain (OR = 0.10; 95% CI [0.015-0.074]; P = 0.023) and reduced LVEF (OR = 0.87; 95% CI [0.79-0.96] P = 0.007) were identified as independent predictive factors of in-hospital outcome. During follow-up, 15 patients experienced at least one cardiovascular event. In multivariable analysis, very extensive (≥ 20%) late gadolinium enhancement (LGE) was found to be a strong prognosticator (HR = 10.65; 95% CI [1.44-78.60]; P = 0.020; Fig. 1 ) in addition to troponin, LV end-diastolic and end-systolic volumes, and reduced LVEF (all P < 0.05). The 5-year event-free survival rate was 95 ± 2% in the LGE < 20% group versus 62 ± 1% in the LGE ≥ 20% group ( p Log Rank = 0.001). During hospitalization, absence of chest pain and reduced LVEF were identified as predictive factors of presenting a cardiovascular event. A very extensive LGE was a powerful long-term prognostic marker.