ObjectivesHybrid stage I palliation (HS1P) has been used in many clinical scenarios including initial palliation in single ventricle (SV) heart disease, a bridge to biventricular repair, a bridge to transplant, and as a destination therapy. There is considerable HS1P practice variation, which we aimed to better understand in this study. MethodsSurvey-based assessment of practice variation related to HS1P was sent to congenital heart centers across the US and Canada. ResultsOf the 106 centers surveyed, responses were received from 54 centers (50.9%). Of respondents, 45 centers perform HS1P. Centers most commonly (97.7%) perform HS1P on “high risk” patients with SV heart disease. Regarding technical aspects of HS1P, most centers (95.3%) accomplish restrictive pulmonary blood flow using PA bands and primarily use changes in oxygen saturation (34.1%) to identify appropriate restriction. Ductal stents are most often used (67.4%) to maintain ductal patency. Only 10 (23.3%) centers routinely enlarge the atrial septal defect (ASD). Indications for ASD intervention varied widely. Most centers (71.9%) discharge patients home to follow with a formal “interstage” program. ConclusionThere is significant variation in practice patterns for HS1P indications, technical aspects, and post-operative care. Therefore, generalizability of single-center studies on outcomes after HS1P is limited. Future multi-center studies are needed to best delineate which patients benefit most from HS1P and to further define optimal approaches to caring for these patients.