Definitions
Cardiac injury was defined if the serum level of high-sensitivity troponin I (hs-cTnI) were above the 99th percentile upper reference limit[2]. The illness severity of COVID-19 was defined according to the Chinese management guideline for COVID-19 (version 7.0). Abnormalities on echocardiography defined as cardiac chambers enlargement, cardiac dysfunction (defined as left ventricular ejection fraction<50%), segment wall motion abnormality, left ventricular wall thickening(>10mm) and/or pericardial effusion. Right ventricular systolic function was represented by the tricuspid anterior plane systolic excursion (TAPSE). Echocardiographic signs of pulmonary hypertension includes the following:the peak tricuspid regurgitation velocity is over 2.8m/s accompanied by the basal diameter ratio of right ventricle/left ventricle >1.0;the acceleration time of pulmonary artery is over 105msec and/or mild systolic notching; the inferior cava diameter is more than 21mm with decreased inspiratory collapse (<50 % in the condition of sniffing or <20 % in quiet inspiration)[3].