Aims Fourteen Dutch heart centres collected patient-relevant outcomes to support quality improvements in a value-based healthcare initiative that began in 2012. This study aimed to evaluate the current state of outcome-based quality improvement within six of these Dutch heart centres. Methods Interviews and questionnaires among physicians and healthcare professionals in the heart centres were combined and results in a mixed-methods approach. The analysis indicates that the predominant focus of the heart centres is on the actual monitoring of outcomes. A systematic approach for the identification of improvement potential and the selection and implementation of improvement initiatives is lacking. The organizational context for outcome-based quality improvement is similar in the six heart centres. Conclusion Although these heart centres in the Netherlands measure health outcomes for the majority of cardiac diseases, the actual use of these outcomes to improve quality of care remains limited. The main barriers are limitations regarding (i) data infrastructure, (ii) a systematic approach for the identification of improvement potential and the selection and implementation of improvement initiatives, (iii) governance in which roles and responsibilities of physicians regarding outcome improvement are formalized, and (iv) implementation of outcomes within hospital strategy, policy documents, and the planning and control cycle.