Effects of beta blockade on work--delta ST segment curves during exercise, and relation to subsequent results of coronary artery bypass surgery.

In 44 patients with coronary disease the relation between work and ST segment depression (AST) was investigated during graded exercise standardised in terms of each subject's maximum work capacity (W max). In 10 patients who were subsequently treated medically (group M) the relation remained unaltered during subsequent studies at three and 12 months. In all patients the effect of beta blockade (3 mg pindolol iv) on the work-AST relation was examined and two groups were identified before surgery on the basis of their response to the beta blocker. In 28 patients who subsequently underwent coronary bypass surgery (group SA) and the 10 patients of group M beta blockade significantly altered the relation so that there was less ST depression