Introduction: Biomarkers, including of B-type natriuretic peptide (BNP) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), are an important clinical tool for prognostic assessment and management of heart failure (HF). However, many clinicians have limited ability to appropriately use biomarkers in clinical practice. Hypothesis: A video-based, online medical education (CME) activity can improve competence and performance of cardiologists and emergency room (ER) physicians related to the use of biomarkers in the management of HF. Methods: An online CME activity was developed as a 25-minute roundtable discussion with 3 leading experts on the use of biomarkers in HF. The activity included a transcript of the discussion and a downloadable slide deck to highlight and reinforce key data. The effects of education were assessed using a linked pre-assessment/post-assessment study design. For all questions combined, the McNemar’s chi-square test was used to assess differences from pre- to post-assessment. P values are shown as a measure of significance; P values <.05 are statistically significant. Cohen’s d was used to calculate the effect size (> 0.8 are large, 0.8-0.4 are medium, and < 0.4 are small). Results: Comparison of individually linked pre-assessment question responses to the respective post-assessment question responses demonstrates statistically significant improvements for both cardiologists (N = 226; P <.05; d=1.549) and ER physicians (n=108; P<.05; d=1.731). Among cardiologists, 5% of participants answered all 4 assessment questions correctly pre-education vs 42% post-education, compared to 2% vs 45% for ER physicians. Significant improvements were observed pre- compared to post-education (all P<.05): • - A 52% relative improvement for cardiologists (61% vs 93%) and a 106% improvement (44% vs 90%) for ER physicians in knowledge of factors which reduce the diagnostic accuracy of BNP and NT-proBNP • - A 116% relative improvement for cardiologists (33% vs 71%) and a 192% improvement (23% vs 68%) for ER physicians in recognition of the additive value of other biomarkers such as ST2 to risk stratify patients • - A 155% relative improvement for cardiologists (24% vs 62%) and a 177% improvement (24% vs 67%) for ER physicians in knowledge of the effect of neprilysin inhibition on BNP and NT-proBNP values • - A 165% relative improvement for cardiologists (29% vs 76%) and a 139% improvement (29% vs 69%) for ER physicians in appropriate use of BNP vs NT-proBNP for patients treated with neprilysin inhibitors Conclusion: The significant improvements observed as a result of participation in this online CME intervention demonstrate that effective internet-based education can deliver content in the context of clinical practice to promote effective knowledge transfer and performance change.