[Value and limits of the tilt-test in the etiological diagnosis of transient malaise]. / Intérêt et limites du test d'inclinaison dans le diagnostic étiologique des malaises brefs.

This study was undertaken to assess the usefulness of the head-up tilt test in the diagnosis of vasovagal syncope and to evaluate the indications of this investigation. The test consists in a 30 minute period in the horizontal decubitus position followed by a 60 degrees head-up tilt position for 30 minutes. In the 26 subjects in whom the diagnosis of repeated vasovagal syncope had been made on the basis of typical prodromic symptoms after exclusion of all other causes, the test induced a vasodepressive or vagal reaction in 10 cases (38%) 20 +/- 4 minutes after tilting. In 8 patients in whom the test was performed within 48 hours of their syncopal episode, a similar malaise was induced in 7 cases. Twenty patients with repeated malaise without loss of consciousness had no symptoms during the test which was also negative in 10 normal control subjects. In a group of 27 subjects with unexplained syncope after clinical and paraclinical investigations, the test was accompanied by a malaise on five occasions (19%). Using this protocol, the tilt test had good specificity but moderate sensitivity in the diagnosis of vasovagal syncope. Its sensitivity increased when performed within 48 hours of syncope. It is of no value in the diagnosis of recurrent malaise without loss of consciousness.