THE CONTRIBUTION OF ISOPROTERENOL TO THE PROLONGED TILT TEST

In this study the tilt test, in combination with isoproterenol adminis tration, was used to investigate 44 patients with unexplained syncope. The reproducibility of the method was studied in a group of 32 patien ts who underwent a second test. The administration of isoproterenol du ring the test increased the sensitivity of the method from 52 to 70% a nd the reproducibility of a positive result from 61% to 83%, at the ex pense of a small decrease in specificity (from 100% to 93%). isoproter enol should thus be considered an essential part of the method, althou gh the low reproducibility of specific types of haemodynamic response limits its value in the choice and the follow up of treatment in indiv idual cases.