Hypoplastic left heart syndrome is the term introduced by Noonan and Nadas1 to describe a spectrum of cardiac anomalies characterized by varying degrees of significant underdevelopment of the left heart and aortic arch. These cardiac anomalies include mitral valvar disease, left ventricular hypoplasia, aortic stenosis at subvalvar, valvar, and supravalvar levels, hypoplasia of the ascending aorta and aortic arch, and aortic coarctation. Although descriptive, hypoplastic left heart syndrome suffers from being a very unspecific term, since it encompasses multiple degrees and combinations of abnormalities involving the left sided structures. In an attempt to provide gradings of severity, Kirklin and Barratt-Boyes2 categorized these patients falling into the syndrome into four classes, according to whether obstruction was found at one, two, or more levels, or whether there is aortic atresia. Then, in 1998, Tchervenkov and colleagues3 introduced the term hypoplastic left heart complex to describe a set of patients falling within the spectrum of hypoplasia of the left heart, but in the absence of intrinsic aortic or mitral valvar stenosis, this concept subsequently being endorsed by the International Committee established by the Society of Thoracic Surgeons, together with the European Association of Cardiothoracic Surgery, to rationalize the approach to nomenclature and databases.4 The analysis offered by Tchervenkov et al.3 showed that, in certain circumstances, there are potentially patients considered to have hypoplasia of the left heart who might be candidates for biventricular repair. If this is the case, then it is important to establish how this subset can be recognized, and how they are best treated.