The in-utero development and treatment of Pulmonary Atresia with intact septum

Pulmonary Atresia with intact septum can be diagnosed by echocardiography from early pregnancy where a spectrum of morphology can be recognised. Important tricuspid regurgitation is common and the right ventricle develops at supra-systemic pressures leading to progressive ventricular hypertrophy and mineralisation that can be seen on serial echocardiograms. This is likely to compromise later ventricular function and only about a third of children achieve an eventual two-ventricle circulation. Fetal valvuloplasty has been proposed as a potential therapy to open the pulmonary valve, reduce right ventricular pressure and improve the potential for normal myocardial development. There is no evidence yet, however, that fetal pulmonary valvuloplasty alters the growth of the pulmonary or tricuspid valves or influences the ventricular size to change the eventual designation, although theoretical benefits in quality of the myocardium may lead to improved outcomes.