EFFECTS OF BISOPROLOL AND ISOSORBIDE DINITRATE ON THE CIRCADIAN DISTRIBUTION OF MYOCARDIAL-ISCHEMIA

The effects of bisoprolol 10 mg once daily, isosorbide dinitrate (ISDN ) 20 mg three times daily, or a combination of these drugs on ischemia during exercise testing and on the occurrence and the circadian varia tion of ischemia during ambulatory monitoring were evaluated in 23 pat ients with stable angina pectoris. ISDN and bisoprolol monotherapies b oth significantly reduced the number of patients with angina pectoris and ST-depression during ergometry while lengthening the time to occur rence of 0.1-mV ST-depression. ISDN did not reduce the number of ische mic episodes measured by Bolter monitoring, although it did significan tly reduce the duration of ischemia. Bisoprolol monotherapy and combin ation therapy significantly reduced the number of ischemic episodes as well as the duration of ischemia, total ischemic burden, and number o f anginal attacks. The circadian variation of ischemia as measured by Bolter monitor was completely abolished by bisoprolol monotherapy and by combination therapy. ISDN monotherapy reduced the evening peak of i schemia but only shortened the morning peak. Both bisoprolol and ISDN reduced ischemia during formal exercise testing, but only bisoprolol e ffectively reduced the total amount of daily life ischemia as measured by ambulatory monitoring.