[Comparison of the effects of diltiazem and isradipine in patients with chronic stable angina pectoris].

In 21 patients with chronic stable angina pectoris stage II-III according to NYHA, by means of bicycle ergometry antianginous and antiischaemic effects of short-term dilthiazem administration (Blocalcin 60, Lachema) were compared with isradipine (Lomir, Sandoz). Dilthiazem was administered in three doses à 90 mg by mouth (midday, evening and subsequent morning), isradipine in a similar way but in three doses à 5 mg. Both preparations reduced, as compared with placebo, significantly the systolic and diastolic blood pressure at rest and the diastolic pressure during a load, dilthiazem also the systolic pressure during a load. Both drugs raised also significantly the total amount of work performed during an ergometric examination, dilthiazem moreover delayed significantly the onset of stenocardia and significantly reduced the ST depression in lead V5 during the maximal load achieved with all administered drugs. A significant increase of the heart rate at rest and in particular of the heart rate during an equal maximal load after isradipine or after placebo, but in particular after dilthiazem, led in comparison with dilthiazem to a significant rise of Robinson's index during the same maximum load and was obviously the cause of its lower anti-anginous and antiischaemic effectiveness. Tachycardia at rest and after a load following isradipine administration led in four patients to a deteriorated load tolerance, as compared with placebo, in another patient tachycardia caused stenocardia at rest with ST depressions on the electrocardiographic tracing. Based on the assembled results, it seems better and safer to use in the treatment of chronic stable angina pectoris dilthiazem rather than isradipine.