univentricular palliation after birth (C–D) This patient had a technically successful procedure and a biventricular outcome LV, Left ventricle (Modified from Freud LR, McElhinney DB, Marshall AC, et al Fetal aortic valvuloplasty for evolving hypoplastic left heart syndrome: postnatal outcomes of the first 100 patients Circulation 2014;130[8]:641.) Compared with patients managed as HLHS, freedom from cardiac death was better among patients with a biventricular circulation at midterm follow-up (Fig 10.7) However, biventricular patients had substantial cardiac morbidity, often owing to residual AS or borderline left heart structures Nearly all patients required postnatal cardiac catheterization and/or surgery Valve replacements were among the most common procedures performed, and 18% of patients required both aortic and mitral valve replacements at midterm follow-up Resection of endocardial fibroelastosis was also performed at the time of cardiac surgery for other indications in 86% of patients.34 Not surprisingly, in addition to the borderline size of the left heart structures, diastolic dysfunction and pathologic LV remodeling may complicate postnatal management.35,36 The borderline left heart structures and diastolic dysfunction resulted in approximately one-third of this population demonstrating pulmonary hypertension, typically in the mild range, at latest follow-up.29 FIG 10.7 Kaplan-Meier curve depicting cardiac mortality between hypoplastic left heart syndrome (HLHS) and biventricular (BV) outcome groups based on the initial postnatal management strategy (Modified from Freud LR, McElhinney DB, Marshall AC, et al Fetal aortic valvuloplasty for evolving hypoplastic left heart syndrome: postnatal outcomes of the first 100 patients Circulation 2014;130[8]:641.) As with other patients with borderline left ventricles, there is no precise formula that will dictate management in the neonatal period However, because the etiologic lesion in this subgroup of patients appears to be the aortic valve, an attempt at postnatal aortic valvuloplasty is reasonable to consider if there is residual obstruction If there is concern regarding the development of severe aortic regurgitation then a surgical valvotomy may be preferred, depending on institutional preference Subsequent hemodynamics will provide critical data as to whether the LV may support the systemic circulation If the left heart remains inadequate, Emani and colleagues have demonstrated that staged LV recruitment, involving aortic and mitral valvuloplasties, resection of endocardial fibroelastosis, and restriction of the atrial septum, may preserve a biventricular outcome.37,38 For patients who proceed down the single ventricle pathway early in life, conversion to a biventricular circulation is possible with reasonable outcome if the LV end-diastolic pressure is relatively low (