Objective:To investigate the risk factors of systolic dysfunction early complicated in patients with isolated traumatic brain injury (iTBI) and to evaluate the influence of complicated systolic dysfunction on the prognosis of iTBI patients.Methods:From January 2017 to October 2018, 123 patients with moderate or severe iTBI admitted to Trauma Centre in our hospital were included in the study, and patients with previous cardiovascular diseases were excluded. Left ventricular systolic function was assessed by transthoracic echocardiography within 24 h after admission. The patients were divided into normal systolic function group ( n=100) and systolic dysfunction group ( n=23) according to the results of echocardiography. Data were collected from all patients on admission, including GCS score, systolic blood pressure, heart rate, high-sensitivity cardiac troponin T (hs-cTnT), clinical treatment variables (use of sedative drugs, vasoactive drugs, etc.), craniotomy or not and clinical outcomes (survival or death) during hospitalization. Logistic regression analysis was used to analyze the related factors for iTBI patients complicated with systolic dysfunction, and receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of each index for iTBI patients complicated with cardiac insufficiency. Results:The systolic blood pressure (147.3±23.3) mmHg, the heart rate (96.1±26.3) beats/min and the hs-cTnT level (16.48±8.17) pg/mL in the systolic dysfunction group were higher than those in the normal systolic function group on admission (all P<0.05); and the GCS score in the systolic dysfunction group was lower than that in the normal systolic function group ( P<0.05). Logistic regression analysis showed that the heart rate ( OR=1.129, 95% CI: 1.001-1.516; P=0.038), the GCS score ( OR=0.640, 95% CI: 0.445-0.920; P=0.016) and the hs-cTnT level ( OR=1.054, 95% CI: 1.009-1.101; P=0.002) on admission were independent risk factors for iTBI patients complicated with systolic dysfunction. The area under the ROC curve (AUC) of the hs-cTnT levelon admission was the largest (AUC=0.863, P<0.01). The in-hospital mortality of patients in the systolic dysfunction group was higher than that of patients in the normal systolic function group (52.5% vs 22%, P=0.004). Conclusions:The heart rate, the GCS score and the serum hs-cTnT level on admission were independent risk factors for iTBI patients complicated with systolic dysfunction. The hs-cTnT level could better predict the occurrence of cardiac systolic dysfuncion, and higher in-hospital mortality was found in iTBI patients complicated with systolic dysfunction. Therefore, early detection and timely intervention may improve the prognosis of these patients.