USEFULNESS OF HEAD-UP TILT TESTING IN UNK NOWN SYNCOPE

The aim of this study was to evaluate the usefulness of head up tilt t esting in patients with syncope of unknown origin. Between January 199 4 and September 1995, 93 patients were referred for tilt table assessm ent due to recurrent syncope of uncertain etiology. There were 42 men (mean age 59 years). Thirty healthy volunteers served as a control gro up. The specific protocol used involved an initial period of supine re st for 15'. Baseline blood pressure (BP) and heart rate (HR) were reco rded. This was followed by a tilt to 80 degrees for 30', BP and HR wer e measured every minute during the procedure. The test was considered positive when symptoms appeared associated with one of the following r esponses: systolic BP decreased more than 30 mmHg (vasodepressor), bra dicardia or asystolia for up to 3 '' (cardioinhibitory) or mixed. Resu lts: The tilt test was positive in 31 of 93 patients (33%). Seventeen patients (55%) had a vasodepressor response, 3 patients (9%) a cardioi nhibitory response and 11 patients (36%) mixed responses. The clinical manifestations were 62% near syncope, 19% syncope and the other patie nts presented dypsnea or dizziness. The symptoms disappeared promptly after adopting the supine position. None of the 30 healthy volunteers developed symptoms. We conclude that head up tilt test is a safe and e ffective method for identifying a neurocardiogenic origin in a syncope of uncertain etiology.