More than 50% of non-healing at one year in “infarct-like” acute myocarditis evaluated by Cardiac Magnetic Resonance

Abstract

Cardiac Magnetic Resonance (CMR) has emerged as a reference tool for the non-invasive diagnosis of myocarditis but its role in follow-up (FU) after the acute event is unknown. We aimed to assess the evolution of CMR parameters between the acute phase of infarct-like myocarditis and 12 months thereafter, and to identify the predictive factors of persistent myocarditis at one year and the long-term prognosis of this infarct-like form. All patients with infarct-like acute myocarditis confirmed by CMR (with typical non-ischemic late gadolinium enhancement (LGE)) were included from April 2012 to January 2017 in this prospective single-center study at Dijon University Hospital. CMR was performed within 7 days following symptom onset, at 3 months and one year after the acute event. One-year FU included ECG, a cardiac stress test, Holter recording, biological assessments, medical history and a quality of life questionnaire. Patients were classified according to the presence or absence of complete healing at one year, based on the CMR evaluation. A total of 85 patients were included. At one year, 44 patients (52%) exhibited persistent myocarditis on CMR. Multivariate analysis showed that high peak troponin at the acute phase (OR 8.2, 95%CI 1.63–41.20, P = 0.011) and the initial extent of LGE (OR 1.1, 95%CI 1.02–1.23, P = 0.019) were independent predictors of persistent myocarditis at one year. No patients experienced major adverse cardiac events (cardiac death or serious rhythm disorders). Moreover, patients with persistent myocarditis were more likely than patients with complete recovery to have premature ventricular contractions during the cardiac stress test (31% versus 6%, P = 0.006). Less than 50% of patients with infarct-like acute myocarditis showed complete healing at one year. Although no MACE were found, these results thus highlight the importance of maintaining long-term FU in patients with infarct-like myocarditis.