This study will test the feasibility of a modified procedure for treating obstructive hypertrophic cardiomyopathy (OHC). Patients with OHC have a thickening of the heart muscle that obstructs blood flow out of the heart, causing breathlessness, chest pain, palpitations, tiredness, lightheadedness, and fainting.

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.

Patients with OHC 18 years of age and older who are scheduled to have a cardiac catheterization may be eligible for this study. At the end of the catheterization procedure, participants will undergo intra-cardiac echocardiographic imaging. For this test, one of the catheters placed in the femoral artery (at the top of the leg) for cardiac catheterization will be substituted for a larger one. Through this catheter, a special catheter will be introduced and advanced to the heart to provide images. This pilot feasibility study does not involve injection of alcohol.