Differential antianginal responsiveness to acebutolol
- 12 Downloads
Six unselected males suffering from documented coronary insufficiency and grade II to III angina were submitted to graded multistage treadmill exercise test on 3 separate occasions, 3.5 hours after ingestion of either 0, 200 or 400 mg of acebutolol, a new cardioselective beta-blocker. Control measures included the random allocation to 6 balanced sequences of administration, the rigid standardisation of double-blind experimental conditions and measurements, and two types of variance analysis (latin-square and split-plot). Performance was evaluated by measuring time elapsed before occurrence of anginal pain and ECG changes, peak heart rate, peak double product (heart rate × systolic pressure), and peak oxygen consumption. The mean values for all 5 criteria showed improvement with the 200 mg dose of acebutolol, and even more so with 400 mg, but this overall effect resulted mainly from the excellent response of 3 of the patients. When patients were grouped into 2 categories of responders and non-responders, a significant Dose × Category interaction was found for all criteria. Furthermore, maximal response under acebutolol was negatively correlated with values under placebo (0 mg); this correlation reached significance for peak heart rate and peak double product. It is concluded that (a) in responders, the beneficial effect of acebutolol was significant on all 5 criteria (p<0.05), (b) patients definitely fell into 2 categories of responsiveness and (c) the sensitivity of responders was partly linked to their performance under placebo and partly to unidentified individual factors.
Key wordsExercise testing exercise protocol angina beta-blocker
Unable to display preview. Download preview PDF.
- 1.Biron, P., Proulx, A., Lapointe, L., Tremblay G., Nadeau, R.: Intravenous acebutolol (M & B 17803 A, Poulenc) in 20 selected cases of cardiac arrhythmia. Clin. Res.21 1015, (1973)Google Scholar
- 2.Frohlich, E.D., Tarazi, R.C., Dustan, H.P.: Beta-adrenergic blocking therapy in hypertension: selection of patients. Int. J. clin. Pharm. Ther. Tox.4 151–156 (1970)Google Scholar
- 3.Lewis, B.S., Bakst, A., Kitchiner, D.J., Gotsman, M.S.: Sectral in the management of angina pectoris. S. Afr. med. J.47 1455–1459 (1973)Google Scholar
- 4.Lindquist, E.F.: Design and analysis of experiments in psychology and education. Houghton Mifflin, Boston (1956)Google Scholar
- 5.Winer, B.J.: Statistical principles in experimental design. 2nd edition. New York: McGraw Hill 1971Google Scholar