Which of the following is the necessary pre-operative investigation which has to be done in a patient with Down's syndrome posted for surgery?

Down's syndrome is associated with cardiac manifestations such as Endocardial cushion defect, ASD, VSD and Tetrology of fallot. So echocardiography is the necessary pre-operative investigation to be done before surgery in a patient with Downs' syndrome. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Page 1382