Background: There is wide variation in rates of both “high-value” noninvasive cardiovascular testing that is recommended by guidelines and “low-value” testing that provides minimal patient benefit. Little is known about what makes hospitals successful in maximizing high-value and minimizing low-value testing. Methods: We used the Colorado all-payer claims database from 2016-2019 to identify hospital use of 1) high-value tests including assessment of left ventricular ejection fraction in patients hospitalized with acute myocardial infarction or incident heart failure, and 2) low-value tests including preoperative stress testing prior to low-risk surgery and routine stress testing within 2 years of coronary revascularization. We identified two “top-performing” hospitals with optimal testing rates (i.e., high-value testing rates in the highest quintile and low-value testing rates in the lowest quintile of hospitals in the state). We performed a qualitative study using in-depth, semi-structured interviews (n=19) with clinical and administrative staff (quality officers, lab directors, and ordering clinicians) at these two “top-performing” hospitals. We examined interview transcripts using directed content analysis to develop our codebook, and analyzed data using a matrix analysis to identify themes that may lead to optimal use of testing. Results: Four main themes were identified: 1) cardiologist involvement (either through screening programs or through direct contact with primary care clinicians); 2) open and direct communication between noninvasive cardiologists and ordering clinicians; 3) a strong sense of mission to deliver high quality and individualized patient care by clinical and administrative staff; and 4) an organizational and leadership culture of approachability and responsiveness to quality improvement initiatives. Conclusions: We identified four themes that characterized the experiences of two hospitals that have optimized use of noninvasive testing. Given the complexity of organizational change to improve care quality, these themes may help hospitals focus future efforts to improve value in testing.