Ambulatory postural blood pressure changes and history allow a better selection of patients that should undergo a head-up tilt test.

BACKGROUND Syncope is a common symptom and in most cases it is of a neurally mediated origin. Such patients have to be studied with a careful history and a physical exploration that should include simple maneuvers such as blood pressure (BP) recordings in decubitus and standing position. These tools can suggest diagnosis in a good percentage of patients without the need for expensive or invasive testing. METHODS We carried out a prospective observational study measuring BP and heart rate (HR) with the patients in decubitus and just as they stood up. The patients were sent for a tilt table test in different specialized centers. The BP changes were compared to the results of the tilt test. RESULTS We included 215 patients, 36.1 ± 18.8 years old, 118 (54.9%) feminine, of which 143 (66.5%) had a positive tilt test. Patients with a positive test showed a rise in systolic BP (SBP) (121.7 ± 19.1 vs. 124.2 ± 20, p < 0.005) and in diastolic BP (DBP) (75 ± 11 vs. 78 ± 11.3, p < 0.005) when compared to people with a negative one. On the other hand, percentage BP changes were significantly different (SBP 2.24% vs. 0.48%, p = 0.02; DBP 4.1% vs. 1.2%, p = 0.009). Patients with a positive test had also a lower HR on standing up (72.1 ± ± 11.1 vs. 78.3 ± 17.2, p = 0.01). CONCLUSIONS Patients with neurally mediated syncope showed an elevation of SBP and DBP when standing up actively, unlike subjects with a negative tilt test.