Backgrounds: Although there is a wealth of information regarding contrast echocardiography (CE) improved visualization of endocardial borders and with regard to improving assessment of left ventricular (LV) function. However, there has been no data about clinical usefulness of contrast agent in portable echocardiography in Korea. The aim of this study was to evaluate the clinical usefulness of contrast agent in portable echocardiography on assessment of ventricular function and clinical diagnosis. Methods: We prospectively enrolled 50 patients (mean age 62 짹 15) from 11 general hospitals in Korea with technically difficult echocardiographic studies who received intravenous contrast Definity (Lantheus Medical Imaging, Billerica, Massachusetts). Of the 50, 30(72%) patients had mechanical ventilator care. Quality of studies, number of visualized LV segments, estimated ejection fraction, ability to identify LV wall motion abnormality, visualization of LV apex, right ventricular (RV) function, any changes in diagnostic procedure and treatment strategy were compared before and after contrast. Results: After contrast injection, the percent of poor or uninterpretable studies decreased from 28.3% to 2.1% (p < 0.001), technically adequate studies increased from 22.9% to 87.8% (p < 0.001) and average number of uninterpretable LV wall motion abnormality was decreased from 86% to 12%. Before contrast, 9.8 of 17 LV segments were seen, which improved after CE to 16.2 (p<0.001). An ability to visualize LV apex was increased from 12.2% to 89.5% (p<0.001) and RV visualization also improved from 14.3% to 30% (p<0.001). A significant impact of CE on management was observed: any changes in diagnostic procedures after CE was 28% of patients and treatment plan was altered in 24% of patients. Conclusions: The utilization of contrast agent in portable echocardiography improves endocardial visualization and impacts cardiac diagnosis and patient management in Asian population.