Blinded or nonblinded procedure for symptomatic new york heart association (nyha) class ii, iii, iva heart failure; transcatheter implantation of left atrial to coronary sinus shunt using jugular vein access, including all imaging necessary to intra procedurally map the coronary sinus for optimal shunt placement (e.g., tee or ice ultrasound, fluoroscopy), performed under general anesthesia in an approved investigational device exemption (ide) study)