This Module is Module 5a in a 13 module eCourse series on Stats, Cardiac Cycle, Basic Echo Exam. For information on the full Pediatric Echocardiography, please click here. We begin the discussion of congenital heart disease with simple shunts, the most common forms of congenital heart disease. The most frequently encountered shunts are ventricular septal defects or VSD. The anatomic variations are discussed and examples will be shown. This will be followed by a similar discussion of atrial septal defects.