3. During the second 2-week period: Subject will then be given either extended release ranolazine or placebo depending on which was received the first time for a total of 2 weeks. Subjects will take 500 mg twice daily for the first 1 week and then 1000 mg twice daily for an additional 1 week. Subjects who are unable to take the higher dose due to side effects will remain on 500 mg twice daily for entire study period. This 2-week period will again be followed by a final Cardiac MRI and questionnaire completion.