Trilogy of Fallot is comprised of pulmonary stenosis, hypertrophy of the right ventricle and an atrial septal defect, and is a distinct clinical entity from Tetralogy of Fallot, one of the most common congenital heart diseases in clinical practice. Very few reports describe this type of heart disease, and the diagnosis can be made only through imaging studies, principally echocardiography.
Although earlier reports suggested that Trilogy of Fallot is not an uncommon CHD , its reports are quite scarce  . Clinical signs and symptoms seem to appear from the congestion of blood in the right heart and the portal system, and congestive heart failure may develop without early recognition  . Similarly to other CHDs, manifestations of cyanosis, clubbing of fingers, and abnormal auscultatory findings during the physical examination are typically encountered in patients suffering from Trilogy of Fallot  .
Clinical suspicion toward any CHD can only be raised with a properly obtained patient history and a meticulous physical examination. The onset and progression of symptoms should be noted, whereas cardiac auscultation is perhaps the vital component of the diagnostic workup. In many patients, a palpable thrill can be detected, and a heart murmur, either at the left base or in the projection of the pulmonary valve, is readily noted   . If cardiac-related manifestations are present and support the finding obtained during the physical examination toward CHD as a possible diagnosis, electrocardiography (ECG) and imaging studies should be employed promptly   . Echocardiography is the primary method for detecting CHDs, including Trilogy of Fallot, and the use of standard 2D and Doppler techniques, as well as the increasingly available 3D imaging, are sufficient methods for confirming the diagnosis   . The benefit of US is that it is able to make the diagnosis prenatally as well, which allows enough time to consider the optimal therapeutic approach.