Predictive Value of Left Ventricular Systolic Dysfunction or Wall Motion Abnormalities for Non-Ischemic Myocardial Injury: A Multicenter Cardiovascular Resonance Study

<b>Background:</b> Left ventricle (LV) systolic dysfunction, defined as a global (LVejection fraction, LVEF < 50%) and/or regional wall motion abnormalities (RWMA), are the major parameters assessed in patients with cardiovascular diseases. The study evaluated the predictive value of LV systolic dysfunction for non-ischemic myocardial injury (presence of myocardial fibrosis/scar) in patients with suspected myocarditis. <b>Methods</b>: This was a multicenter, observational, retrospective study (2018-2021) of stable outpatients with clinically suspected myocarditis referred for a contrast-enhanced CMR. Patients with a history of any other significant cardiovascular disorders were excluded from the study. In each patient, the LV systolic function (LVEF, RWMA) and the presence and severity of late gadolinium enhancement (LGE) were assessed by CMR. <b>Results</b>: A total of 773 consecutive patients were enrolled in the study. The average LVEF was 58 ± 10%, and systolic dysfunction was observed in 95 cases (12%). Subsequently, 456 patients (59%) with confirmed non-ischemic LGE in at least one segment were included in the study group. The average LVEF was 57 ± 11%, with LV systolic dysfunction observed in 126 (28%) individuals with RWMA and 84 (18%) with LVEF < 50%. The median number of LV segments with LGE was 3 (2-5), and the total amount of LGE was 6% (3-10) of the LV mass. The wall motion score index (WMSI) > 1 and LVEF < 56% were the best predictors of non-ischemic injury based on LGE (area under the curve [AUC] 0.62; sensitivity 31%; specificity 94%; <i>p</i> < 0.001 and AUC 0.59; sensitivity 42%; specificity 75%, <i>p</i> < 0.001, respectively). <b>Conclusions</b>: In stable patients with suspected myocarditis, any RWMA and LVEF < 56% had a predictive value for a non-ischemic myocardial injury as assessed by CMR.