Bisoprolol in the treatment of angina pectoris: a double blind comparison with verapamil

In order to verify the anti-ischaemic effect of a new beta-blocking agent, bisoprolol, a double blind parallel groups trial was carried out in comparison with verapamil. 26 patients with a history of spontaneous and/or effort angina were studied. After a two-week treatment with placebo, they were randomized in two groups. One group was treated for 4 weeks with bisoprolol 10 mg o.d. and for the following 4 weeks with bisoprolol 20 mg o.d. The other group received verapamil 80 mg t.i.d. for the first 4 weeks and 120 mg t.i.d. for the remaining 4 weeks. Throughout the study isosorbide dinitrate 20 mg b.i.d. was administered and sublingual nitroglycerin was allowed when necessary. 21 patients completed the study. Both bisoprolol and verapamil significantly reduced the number of angina episodes and nitroglycerin tablets consumption, as well as ischaemic episodes recorded on Holter ECG. The total number and severity of ectopic ventricular beats were reduced too. On multistage treadmill exercise test, both drugs increased effort time and time to ST depression = 1 mm, and reduced ST depression and double-product. The effect of bisoprolol on double product was greater than that of verapamil because of the better control of heart rate. The relationship ST/double product suggested that beta-blockers act essentially through the reduction of myocardial oxygen consumption and verapamil possibly with an additive effect on coronary circulation. Radionuclide ventriculography showed no deterioration of rest ventricular function with both drugs. In conclusion, bisoprolol and verapamil showed a satisfactory anti-ischaemic effect, with good tolerability.