Feasibility of cardiac magnetic resonance for assessing atrioventricular block in acute myocarditis

The incidence of conduction block in acute myocarditis (AM) is 10% and atrioventricular block (AVB) is generally associated with LV dysfunction and HF.Patients presenting with symptoms of HF have worse prognosis compared with those presenting with chest pain.High-grade atrioventricular block is recognized as a critical criterion for identifying high-risk or complicated myocarditis.However, research specifically focusing on myocardial tissue characteristics identified by CMR in myocarditis patients with AVB remains limited.Therefore,the objectives of the present study are to investigate the performance of CMR tissue characterization parameters in patients with AM and AVB, and to evaluate their diagnostic utility in differentiating these patient groups.Furthermore, it aims to analyze the association between CMR tissue parameters and clinical outcomes to provide an imaging basis for the early identification of poor clinical outcome.We demonstrated that the advanced AVB group had considerably elevated ECV values across multiple segments ,while other tissue parameters had no significant differences. Additionally,the ECV of the basal superior ventricular septum effectively discriminated between non-advanced AVB and advanced AVB.Notably,adverse clinical outcomes occurred exclusively in three patients from the advanced group who had elevated ECV of the basal superior ventricular septum.