As part of Amendment 2 (submitted November 2013), subjects who continue on ranolazine after the 6 month treatment period (as part of their clinical care) will be asked to return for further follow-up testing to better assess the safety and efficacy of the drug. The visit can be conducted once the patient has been on drug for a total of one year or greater (including the 6 month treatment period). This would replace the 1 Year follow-up visit for subjects who have not yet completed the visit and will be an additional visit for those subjects who have.