Nitrate-potentiated head-up tilt testing in older patients: outcomes, hemodynamic responses and prodrome recognition

BACKGROUND: To compare head-up tilt testing (HUT) outcomes and hemodynamic responses, and the prevalence and correlates of prodromes, in elderly and younger patients with suspected vasovagal syncope (VVS). METHODS: Consecutive outpatients with a history of recurrent unexplained syncope underwent HUT by being tilted to 70°; the test was potentiated by the administration of 300 μg of nitroglycerine after 20 minutes. Occurrence of VVS and hemodynamic responses during passive and nitroglycerine phases of HUT were evaluated; symptoms preceding HUT-induced syncope were recorded, together with heart rate and arterial blood pressure values. RESULTS: Four hundred and sixty of the 743 patients were HUT positive: 156 fainted during the unmedicated phase and 304 after nitroglycerine administration. The patients aged ≥65 years (n = 102) experienced VVS more frequently during the pharmacological stage of HUT; the overall rate of positive results was similar to that observed in the patients aged 36-64 years (n = 329) and only slightly lower than that observed in those aged ≤ 35 years (n = 312). In the older patients, who experienced fewer and mainly prodrome-free spontaneous syncopal episodes, HUT increased the number of premonitory symptoms, and there were no significant age-related differences in symptom prevalence or timing or the patients' hemodynamic characteristics. CONCLUSIONS: The rate of VVS induced by nitroglycerine-potentiated HUT is similar in elderly and younger patients. In the former, nitroglycerine-potentiated HUT significantly increases the prevalence of prodromes in comparison with spontaneous episodes, which suggests that it may be useful not only for diagnosis but also for patient counseling.