Optimising short-and long-term outcomes for children and patients with CHD depends on continued scientific discovery and translation to clinical improvements in a coordinated effort by multiple stakeholders. Several challenges remain for clinicians, researchers, administrators, patients, and families seeking continuous scientific and clinical advancements in the field. We describe a new integrated research and improvement network -Cardiac Networks Unitedthat seeks to build upon the experience and success achieved to-date to create a new infrastructure for research and quality improvement that will serve the needs of the paediatric and congenital heart community in the future. Existing gaps in data integration and barriers to improvement are described, along with the mission and vision, organisational structure, and early objectives of Cardiac Networks United. Finally, representatives of key stakeholder groupsheart centre executives, research leaders, learning health system experts, and parent advocatesoffer their perspectives on the need for this new collaborative effort.Clinical outcomes for children and patients with CHD improved considerably over the past several decades. However, several domains still pose a challenge to clinicians and researchers seeking to optimise care and outcomes for these children and families. Early morbidity and mortality remain high for patients undergoing high-complexity surgery. Data on outcomes from across the lifespan are scant, but those that exist suggest burdensome physical and functional morbidities across multiple domains. Finally, there remains substantial variability in care, outcomes, and costs across hospitals in providing care for these patients.To find a mechanism to address these challenges, the field of paediatric and CHD has invested considerably in recent years to improve data capture and analysis from multiple sources in order to learn and improve. Although these efforts have led to several notable advances, 1-6 important limitations remain. These include lack of integration across data sources that limits our capabilities to drive discovery across the lifespan, limited mechanisms to translate knowledge gained from these data into tangible improvements in patient care and outcomes, and the overall cost and sustainability of such efforts. Many children's hospitals that participate in clinical data registries and other networks report spending in excess of $500,000-1,000,000 per year to support the necessary personnel and infrastructure, and the key stakeholders have voiced concerns regarding inadequate return on that investment in relation to scientific discovery and improvements in clinical outcomes. A new paradigm for this work is necessary to maximise the value of these data and accelerate discovery and Cardiology in the Young