a technique for percutaneous treatment of idiopathic hypertrophic subaortic stenosis and hypertrophic cardiomyopathy . ihss and hcm are diseases of the heart in which the septum of the left ventricle thickens resulting in reduced ventricular performance . current treatments involve drug therapy or a medical intervention called an interoperative myotomy / myectomy using the morrow procedure . the present invention uses laser energy delivered via fiber optics placed percutaneously to irradiate the thickened septum to reduce tissue volume of the septum and enhance left ventricular function .