- OBJECTIVE: To examine whether explaining causal links among endothelial pathophysiology, cardiac risk factors, symptoms and health behaviors (termed causal information) enhances patients' depth of knowledge about cardiovascular disease self-management and their perceptions of the cardiac rehabilitation and secondary prevention (CRSP) program. METHODS: Newly referred CRSP patients (N = 94) were cluster randomized to usual care (control; UC) or usual care with causal information (intervention; UC + CI). Depth of knowledge (factual vs. deep) was measured with an adapted cognitive-reasoning task. Patients' cardiovascular knowledge and beliefs about the efficacy of a CRSP program were assessed. RESULTS: After controlling for education level, patients in UC + CI demonstrated deeper knowledge about cardiovascular management than did those in UC. The UC + CI group showed higher factual knowledge than their counterparts after covarying education, occupation status and BMI. The UC + CI group also rated the CRSP program as more credible than those in UC, after controlling for age. Deep knowledge mediated the relationship between group conditions and perceived credibility of CRSP. CONCLUSION: Causal information can enhance the depth of patients' understanding of cardiovascular disease management and perceived treatment credibility of the CRSP program. PRACTICE IMPLICATIONS: Explaining causal links may help improve patient education delivery and enhance patient engagement in CRSP.