TILT TEST - HEMODYNAMIC-RESPONSES IN PATI ENTS WITH SYNCOPE OR PRESYNCOPE OF UNKNOWN ETIOLOGY

The aim of this work was to assess the hemodynamic responses to the ti lt test of 51 patients with syncope (n = 31) or presyncope (n = 20) of unknown etiology. A protocol with an inclination of 70-degrees (20 mi n) with or without isoproterenol (mean dose of 3.6 +/- 0.3 mug/min), w as used. Forty five percent of patients had a positive test, 18 with i soproterenol at 70-degrees (group 1A) and 5 without isoproterenol (gro up 1B), 28 patients had a negative test (group 2). These groups did no t differ in age or sex distribution. Basal heart rate was 76.2 +/- 2x. At the end of the test it was 73.4 +/- 5.7 in group 1A, 78.0 +/- 7.5 in group 1B and 120.4 +/- 3.3 in group 2 (p < 0.01). Systolic blood pr essure decreased to 78.1 +/- 4.8 mmHg in group 1A, to 76.2 +/- 9.9 in group 1B and did not decrease in group B (130.0 +/- 5.7 mmHg, p < 0.01 ). The required dose of isoproterenol was higher in group IA than in g roup 2 (4.4 +/- 0.3 vs 3.1 +/- mug/min, p < 0.01). It is concluded tha t the tilt test reproduced symptoms and accompanying hemodinamic mecha nisms in a high proportion of patients with syncope of unknown etiolog y. This test should be incorporated in the diagnostic workup of these patients.