Systolic anterior motion (SAM), a recognized complication of mitral valve repair, is often associated with left ventricular outflow gradient and mitral regurgitation. Current surgery to prevent these conditions is to perform sliding annuloplasty to reduce the posterior mitral leaflet (PML) height and to oversize the annuloplasty ring. However, these techniques do not consistently eliminate post-repair SAM, and removal of excess tissue and reduction of anterior mitral leaflet (AML) height may be more effective; this is the 'Pomeroy procedure'. Here, we report a patient in whom all standard procedures to prevent SAM were performed, but the condition still developed. This was corrected on a second pump run, using the Pomeroy procedure.