2.1. Study population
DCM
Between July 1, 2016 and July 1, 2021, we retrospectively consecutively enrolled 117 DCM patients admitted to the first Hospital of Jilin University as the DCM group, while 117 patients hospitalized in the same period with normal echocardiography and ECG were selected as the non-DCM group. The diagnosis of DCM was based on symptoms, laboratory, and echocardiography. The inclusion criteria for the DCM group were as follows: age ≥ 18 years; Patients underwent 12-lead ECG and echocardiography and the relevant results were stored completely after admission; ECGs were in sinus rhythm; Patients were diagnosed as DCM by echocardiography following the diagnosed criteria that echocardiography showed left ventricular end-diastolic diameter (LVEDD) > 5.0 cm (female) or 5.5cm (male) and left ventricular ejection fraction (LVEF) < 45% according to the guideline protocol of diagnosis of DCM from the British Society of Echocardiography.