EFFECT OF SUSTAINED-RELEASE DILTIAZEM (DILTIAZEM-R) IN PATIENTS WITH STABLE EFFORT ANGINA

Ca++-antagonist is effective not only for variant angina but also for effort angina. The effects of sustained release diltiazem (diltiazem-R ) and beta 1-blocker (atenolol) on exercise tolerance were studied in seven patients with stable effort angina in a cross over trial. Diltia zem-R (100mg) or atenolol (50mg) was given once a day, each treatment period lasting for two weeks after a two-week control period. The trea dmill exercise test was performed on the last day of each protocol. Bo th diltiazem-R and atenolol decreased heart rate at rest and the decre ase with atenolol was greater than that with diltiazem-R. The systolic blood pressure was unchanged at rest by both drugs. At maximal work l evels, atenolol decreased the heart rate and pressure rate product sig nificantly, but diltiazem-R did not. Both diltiazem-R and atenolol sig nificantly prolonged the exercise time (average 137 and 165 seconds re spectively), time to onset of 1mm ST depression (240 and 288 seconds r espectively). There was no significant difference in exercise toleranc e between diltiazem-R and atenolol. These findings suggest that diltia zem-R, a sustained release Ca++-antagonist, provides beneficial effect s in patients with stable effort angina.