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.
Patients with obstructive hypertrophic cardiomyopathy (HCM) and drug-refractory symptoms
have traditionally been referred for cardiac surgery to widen the left ventricular (LV)
outflow tract. More recently, percutaneous transluminal septal ablation (PTSA) has also
been shown to thin the subvalvular septum and thereby to reduce LV outflow pressure
gradients and to improve symptoms in obstructive HCM. However, this procedure is not
infrequently limited by septal coronary artery anatomy and inability to identify and
cannulate the appropriate artery that supplies the septal region of interest. Some attempts
are also associated with coronary artery dissection, particularly, if there is associated
coronary artery disease. A trans-right ventricular (RV) alcohol septal ablation (TRVASA)
would significantly simplify the procedure, and increase its safety. The purpose of this
study is to initially test our ability to visualize and guide a delivery catheter to a
targeted part of the anterior interventricular septum involved in the generation of the LV
outflow obstruction using intracardiac echocardiography (ICE). No therapy is intended:
alcohol will not be injected into the septum in this initial study.
Patients of either gender, aged 18-85 years.
Symptomatic patients receiving clinically indicated evaluation for cardiomyopathy and
found to have obstructive HCM.
LV outflow tract gradient greater than 30 mm Hg at rest by echocardiography or cardiac
Positive pregnancy test.