(A) The primary consequence of KATP GOF in the vasculature is reduced excitability, leading to functional and structural vasodilation, low blood pressure, and underperfusion. Secondarily, this leads to a compensatory cardiac hypertrophy and hypercontractility. (B) These features are present in even mild (e.g., SUR2wt/AV) CS models, but are exacerbated in more severe genotypes (e.g., Kir6.1wt/VM and SUR2AV/AV). The latter genotypes are associated with premature death, and very early death occurs immediately after weaning in the most severe genotypes (e.g., SUR2wt/AV/Kir6.1wt/VM and Kir6.1VM/VM).