Borderline Left Ventricle: Criteria for Surgical Decision Making With an Emphasis on Cardiac Magnetic Resonance Imaging.

The borderline left ventricle (LV) encompasses a heterogenous group of cardiac defects that result in underdevelopment of the left heart. Data supporting decision making is difficult to interpret because borderline LV hypoplasia is a relatively rare disease comprising of a heterogenous morphologic spectrum with data originating from single-institution retrospective studies that have all used varying inclusion criteria and imaging modalities/analysis methods, whilst further confounded by heterogenous institutional practice patterns and era effects. Long-term data is lacking. This invited expert review offers a perspective on how to interpret and use some of the preoperative imaging parameters commonly proposed to decide between primary biventricular repair (BVR) versus LV recruitment. The need to integrate functional cardiovascular magnetic resonance imaging (CMR) parameters is emphasized. Current approaches and a broad framework with imaging criteria are presented.