Instructional Revision, Facilitator-Supported Practice, and Cardiac Auscultation Performance: A Seven-Cohort Observational Study

Review of objective structured clinical examination (OSCE) results identified aortic sclerosis as the lowest-performing Harvey simulator station, with faculty reporting that students confused it with aortic stenosis because both present with systolic murmurs. Instruction was revised to emphasize carotid palpation and murmur radiation, the distinguishing finding, but performance did not improve. Facilitator supervision was later added to existing extended-hours practice without increasing simulator availability, allowing supervision to be examined independently of access. We analyzed seven consecutive OSCEs delivered under one curriculum and one machine-scored 14-item instrument (1,121 student-station observations, 2024 to 2026). The revision took effect in Fall 2024; four facilitators joined practice sessions from Summer 2025, intervening only when students encountered difficulty. The primary outcome was performance at the aortic sclerosis station, named in monitoring records before either intervention; mitral valve prolapse, whose diagnostic feature is independent of the revised maneuver, served as a comparison outcome. The revision alone produced no improvement, with performance across the three preceding cohorts flat to declining (83.3%, 82.2%, 81.1%). After facilitators were added, aortic sclerosis rose from 81.7% to 89.9%, a difference-in-differences of 7.87 points (95% CI 3.06 to 12.69, P = 0.001), and students scoring below 70 fell from 25.9% to 12.0%. Overall performance rose from 82.4% to 88.3% (5.65 points, 95% CI 0.87 to 10.43, bootstrap P = 0.016), while the comparison station changed by 0.40 points (P = 0.84). Facilitator-supported practice may provide educational benefit beyond access to simulation resources alone.