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 variation of ischemia during ambulatory monitoring were evaluated in 23 patients with stable angina pectoris. ISDN and bisoprolol monotherapies both significantly reduced the number of patients with angina pectoris and ST-depression during ergometry while lengthening the time to occurrence of 0.1-mV ST-depression. ISDN did not reduce the number of ischemic episodes measured by Holter monitoring, although it did significantly reduce the duration of ischemia. Bisoprolol monotherapy and combination therapy significantly reduced the number of ischemic episodes as well as the duration of ischemia, total ischemic burden, and number of anginal attacks. The circadian variation of ischemia as measured by Holter monitor was completely abolished by bisoprolol monotherapy and by combination therapy. ISDN monotherapy reduced the evening peak of ischemia but only shortened the morning peak. Both bisoprolol and ISDN reduced ischemia during formal exercise testing, but only bisoprolol effectively reduced the total amount of daily life ischemia as measured by ambulatory monitoring.