BACKGROUND: Heart failure is a condition with significant symptom burden and high hospitalization rates. Effective self-management, including recognizing symptoms and making behavior changes, is crucial but often inadequately addressed by current educational methods. To improve this, heart failure self-care vignettes were developed to measure knowledge of managing physical and psychological symptoms. However, the vignettes' face validity and reliability have not been thoroughly evaluated. OBJECTIVE: To ensure the understandability of a novel instrument to measure knowledge of heart failure symptom recognition and self-management and to examine its inter-rater reliability with individuals diagnosed with heart failure. METHODS: Cognitive interviews were conducted with heart failure patients admitted to an academic hospital in the Midwest U.S. Vignette segments and interview questions were analyzed, totaling 74 items. Five patients aged 65 and older, participated without cognitive, visual, or hearing impairments. The interviews were coded by two independent raters using a cognitive interview coding book. Vignettes were evaluated qualitatively with a 3-point Likert scale (1 = misunderstanding, 2 = partial understanding, and 3 = full understanding). Inter-rater reliability was assessed using percent agreement and Cohen's kappa. RESULTS: Patients understood an average of 76% of the psychological and 83% of the physical vignette items, indicating acceptable preliminary understandability. Inter-rater reliability was moderate, with Cohen's kappa values of 0.39 (psychological) and 0.43 (physical). CONCLUSIONS: This pilot study suggests that vignettes could be a useful tool for assessing knowledge of symptom recognition and self-management. Cognitive interviewing helped evaluate how vignette segments were interpreted before using them in future data collection.