After the first course of study treatment, the patient will undergo a two week wash-out with no study drug while continuing usual medication regimen. Following the washout period, study participants will start the second cycle of study drug treatment (i.e., the other study drug not received in treatment 1). At visit 3, participants will undergo baseline 2 measurements which include concurrent medication and symptom assessment, clinical measurements (weight, BP, waist and hip circumference) and will complete baseline 2 questionnaires (SAQ, WISE angina frequency, DASI and SF-36). Study drug treatment #2 will follow the same escalation of study drug dose as described above for treatment 1. The final study CMR (CMR 2) will be scheduled at the end of the 4th week of treatment 2, approximately 4 hours after the morning dose of study drug. At this visit (Vis 4), concurrent medications, symptoms, and adverse events will be reviewed. Clinical measurements will be taken (weight, blood pressure, waist and hip circumference) and questionnaires will be completed (SAQ, WISE angina frequency, DASI and SF-36). [See Table 1 for a listing of all study procedures by visit.] The two post study drug treatment CMRs will be performed at the same time of day, replicating temperature, fasting state, adenosine dosing and infusion, magnet settings and using the same over-reader. The dose of adenosine will be consistent for all study CMR tests: 140 mcg/kg over 5 minutes.