We wish to see if the drug rosiglitazone, currently used in the treatment of type 2 diabetes, could be used as a new treatment for angina when compared with placebo in overweight subjects who do not have overt diabetes. The drug will be given for 3 months and the subjects will be have their angina tested, by way of exercise testing, angina quality of life questionnaire and 24-hour ECG monitoring before and after using the drug.