Dissociation between clinical and exercise responsiveness to beta-blockade in angina.
Twenty outpatients with mild angina were prescribed placebo tablets b.i.d. for 7 weeks followed by acebutolol, a cardioselective beta-blocker, 200 mg b.i.d. for 21 weeks under single-blind conditions. One graded multistage treadmill test was carried out after each treatment period and an angina diary was filled daily for the 6 months of the trial. Attack frequency declined by 71% from 2.59 per week on placebo to 0.76 per week on acebutolol (p less than 0.05). Exercise duration on the treadmill increased by 56%, from 5.95 minutes on placebo to 9.32 minutes on acebutolol (p less than 0.001). A satisfactory clinical response (50% or greater decline in attack frequency per week) occurred in 15 out of 19 patients (79%; a 100% or greater increase in exercise duration on the treadmill was observed in 10 out of 19 cases (53%). Exercise responsiveness was well predicted by exercise duration on placebo (r = 0.91, p less than 0.0005), patients with the least initial tolerance being the most improved. Clinical responsiveness was not well predicted by initial exercise tolerance (r = 0.38, N;S.) or by the improvement in exercise tolerance (r = 0.33, N.S.). It is concluded that acebutolol substantially reduces anginal attack frequency even in patients in whom exercise tolerance is not significantly improved, at the dose of 400 mg/day.
D000070:Acebutolol / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000188:drug therapy / Q000503:physiopathology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D010919:Placebos
D000319:Adrenergic beta-Antagonists; D010919:Placebos; D000070:Acebutolol