This is a 6 month, single center, prospective, open-label trial. All subjects will be receiving active treatment, ranolazine at doses approved by the FDA. Subjects will begin treatment at 500mg twice daily and increase to 1000mg twice daily as tolerated after 2 weeks. Subjects will take study drug twice daily with or without food. Ranolazine will be limited in subjects taking CYP3A including diltiazem, verapamil, arprepitant, erythromycin, fluconazole, grapefruit juice or grapefruit juice containing products. The study will consist of 3 periods: a screening period, a treatment period, and a follow-up period.