Table 2.

Cyanotic congenital heart diseases.

Cyanotic CHD	Brief Description
Tetralogy of Fallot (TOF)	A common cyanotic CHD; characterized by pulmonary stenosis/right ventricular outflow tract obstruction, VSD, over-riding aorta and hypertrophy of the right ventricle
Transposition of the great arteries (TGA)	Discordant ventriculoarterial connection—the right ventricle is connected to the aorta (instead of pulmonary artery), and left ventricle to pulmonary artery (instead of aorta)
Double outlet right ventricle (DORV)	Both the aorta and pulmonary artery arise predominantly or completely, from the right ventricle
Persistent truncus arteriosus	Failure of septation of the primitive truncus into the aorta and pulmonary artery, resulting in a single, common arterial trunk that overlies a large VSD
Hypoplastic left heart syndrome (HLHS)	Underdevelopment of the left-sided structures of the heart, including the ascending aorta, left ventricle and aortic and mitral valves

Note: TOF, TGA, DORV, and persistent truncus arteriosus are collectively known as conotruncal defects, as these lesions involve the conus and truncus arteriosus of the embryonic heart.