[Diagnosis of left-to-right shunt. Dye dilution curves in patients with left-to-right shunt during physical exertion and after beta-receptor blockade].

In 79 patients, suffering from central left-to-right shunts, dye-dilution curves were recorded partially using a peripheral venous injection site during reactive hyperaemia. 47 investigations were carried out during ergometer exercise in supine position. 32 patients received injections of 1-2 mg Propranolol or 0,4-0,8 mg Pindolol. During exercise dye-dilution curves showed characteristic alterations, indicating a decrease of the relative shunt-flow, whereas beta-receptor blocking agents increased the relative shunt-flow. Dye-dilution curves written during exercise may be helpful in evaluating the indication for operative closure in patients with small atrial or ventricular septal defects. beta-receptor blocking agents can facilitate diagnosis of left-to-right shunt as a screening test.