Spectrum of hypoplastic left heart syndrome

The spectrum of HLHS.
(A) Mitral atresia and aortic atresia. This is the most extreme form of HLHS. The LV is diminutive or absent. The ascending aorta is severely hypoplastic. Systemic output is ductal-dependent with retrograde flow in the ascending aorta.
(B) Mitral stenosis and aortic atresia. The ascending aorta is severely hypoplastic, and systemic output is ductal-dependent. Depending on the degree of mitral stenosis, LV pressures may be subsystemic, systemic, or even suprastemic. The degree of ventricular hypertrophy is also variable, but there is usually severe LV systolic dysfunction.
(C) Mitral stenosis and aortic stenosis. There is considerable variability in the size of the LV, amount of antegrade flow, and degree of LV systolic and diastolic dysfunction, depending on the degree of obstruction from the combined effect of the mitral and aortic stenosis. The ascending aorta is larger than in patients with aortic atresia. There is overlap in the spectrum of these patients and those with critical aortic stenosis, allowing some patients to be considered for a two-ventricle repair.