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Hypoplastic left heart syndrome consists of several defects - mitral and aortic valve, aorta, and left ventricle. The question came up about whether other related conditions should be separately coded out with ICD-9 codes (mitral stenosis/atresia, aortic valve stenosis, coarctation of the aorta/aortic arch) or if all of these conditions associated with hypoplasty left heart syndrome would fall under the one ICD-9 code.