The purpose of this study is to find out whether mitral regurgitation (or a leaky heart valve) caused by ischemic heart disease (decreased blood flow to heart muscle) will improve after administration of ranolazine.

Inclusion Criteria:

• Ischemic cardiomyopathy AND
• Moderate or severe mitral regurgitation AND
• Cardiac resynchronization therapy (CRT) ≥ 3 months prior to enrollment AND
• Maximal Medical Therapy (ACE-Inhibitor, beta blocker, aldosterone antagonist, diuretic, aspirin, statin)

Exclusion Criteria:

• nonischemic cardiomyopathy
• active heart failure
• current ranolazine therapy
• congenital heart disease
• mechanical valve prostheses
• vegetation/endocarditis
• significant pulmonary disease
• peripheral vascular disease
• trivial or mild mitral regurgitation
• creatinine clearance < 30 mL/min
• liver cirrhosis
• strong inhibitors of CYP3A (including ketoconazole, itraconazole, clarithromycin, nefazodone, nelfinavir, ritonavir, indinavir, and saquinavir)
• strong inducers of CYP3A (including rifampin, rifapentine, phenobarbital, phenytoin, carbamazepine and St.John's wort)
• Strong P-glycoprotein inhibitors (including cyclosporine, verapamil, and quinidine)
• Initial QTc interval ≥ 440msec