More than 30% of symptomatic patients at one year in “infarct like” acute myocarditis

Background The persistence of symptoms after infarct-like acute myocarditis remains unclear. The objectives of this study were to identify the predictive factors of persistent symptomatic patients at one year in “infarct like” myocarditis. Methods All patients with infarct-like acute myocarditis confirmed by CMR (with typical non-ischemic late gadolinium enhancement (LGE)) were included from 2012 to 2018 at Dijon University Hospital. CMR was performed in the acute phase, at 3 months and 1 year after the acute event. One-year FU included ECG, cardiac stress test, Holter recording, biological assessments, medical history and a QoL questionnaire. Patients were classified according to symptoms (chest pain or dyspnea) at one year. Results 111 patients were included. At one year, 31% of the patients report symptoms while 53% of them had persistent myocarditis on CMR. Among symptomatic patients, 23% reported intermittent chest pain and 20% reported dyspnea. One patient experienced cardiac death before the one-year CMR control and had persistent myocarditis at 3 months. The predictive factors of persistent symptoms at 1 year were left ventricular dysfunction (P = 0,005) and wall abnormalities (P = 0,005) on one year CMR, and hospitalization in the year (P = 0,002). Nevertheless, symptomatic patients more often had beta blocker treatment than asymptomatic patients (17% vs. 48%, P = 0,001). The initial extent of LGE and persistent myocarditis on CMR at one year didn’t seem to be predictors of the persistence of symptoms. Conclusion On third of patients with “infarct like” acute myocarditis reported persistent symptoms at 1 year while less than 50% of patients showed complete healing at one year. Persistent symptoms appear to be more related to left ventricular dysfunction than persistent myocarditis, and are associated with greater cardio-protective therapy. These results thus highlight the importance of maintaining long-term FU in patients with infarct-like myocarditis.