Curriculum congestion, which has arisen from an increasing knowledge base, forces many students to take a pragmatic approach to their learning; rote learning from didactic lectures. This approach may allow students to pass examinations but limits their ability to integrate and apply their knowledge. Moreover, large cohorts impact on our ability to provide sufficient opportunities for students to consolidate lecture content and test their understanding of and ability to apply core concepts, eg small groups tutorials. We sought to identify ways in which we could address these challenges for a cohort of 350 year 2 MBChB students studying cardiovascular science at the University of Birmingham. From performance in small group teaching sessions and summative assessments over a number of years we identified that students were able to recall basic details of the cardiac cycle but were unable to apply their knowledge to simple clinical cases. Thus we reduced didactic lecture content and introduced an interactive session in which 90 students were given a Wiggers diagram and were asked to accurately plot left ventricular pressure against volume for one cardiac cycle; they had not previously seen a P-V loop. To test their understanding of the physiological principles underlying pressure generation, valve opening and blood movement we asked them to mark on their loop the points at which the aortic and mitral valves open and close, to indicate end diastolic and end systolic volume and to calculate stroke volume and ejection fraction. With only one lecturer facilitating the session, we used peer instruction (Lasry et al, 2008) to enable students to complete the task. The activity was extended by asking the students to discuss and illustrate what would happen to the P-V loop with changes in pre-load, inotropy and after-load, giving them the opportunity to explore this before subsequent teaching on regulation of cardiac output. Evidence from performance in summative assessments suggests that this activity increased the students’ understanding of the cardiac cycle and their ability to apply the physiological principles underlying it. Student feedback on the session was very positive, interestingly however, a significant minority of students expressed a wish to have more facilitators in the sessions, suggesting that there are a number of students who are not confident in their ability to learn when they are not being lectured didactically. This could be ameliorated by explaining to students the rationale for and the benefits of this type of learning. This approach could be applied in any area in which curriculum pressure has forced students to rely largely on rote learning and in which large cohort size limits how resources can be used to provide students with opportunities to test their own learning.