The current treatment for OHC is a procedure called alcohol septal ablation (also percutaneous transluminal septal ablation, or PTSA), which involves injecting a small amount of alcohol into a tiny artery that supplies the part of muscle causing blood flow obstruction. The success of PTSA is limited, however, by problems of heart anatomy and the ability to find the appropriate artery to inject. Modifying the procedure by injecting the alcohol through the wall of the lower right chamber of the heart may improve its safety and effectiveness. The new technique requires positioning a catheter (a flexible tube) into the appropriate area of the heart. This study will test the ability to accurately guide the catheter to that area.