Responses to the prolonged head-up tilt followed by sublingual nitrate provocation in asymptomatic older adults

Background: prolonged head-up tilt testing and sublingual nitrate provocati on are increasingly used in the diagnosis of neurocardiogenic syncope. Howe ver there are few data regarding the results of these tests in asymptomatic older subjects. Objective: to assess the responses to the prolonged head-up tilt test follo wed by sublingual glyceryl trinitrate provocation in asymptomatic subjects over the age of 60 years. Design: observational study. Methods: we recruited 64 asymptomatic subjects over the age of 60 (39 men, 25 women) from two general practice lists in Nottingham and Leicester. Excl usion criteria were: history of syncope, ischaemic heart disease, cerebrova scular disease, marked aortic stenosis, carotid artery disease and being un able to stand for the duration of the test. hll subjects underwent a full c linical examination, a 12-lead electrocardiogram and a 30-40-min head-up ti lt test, during which we monitored the heart rate and blood pressure contin uously. We ended the test prematurely if the subjects developed syncope or symptoms of presyncope associated with hypotension with or without bradycar dia. If they remained asymptomatic at the end of this period, they received 400 mug of sublingual glyceryl trinitrate and monitoring continued for ano ther 15 min. Settings: two teaching hospitals in Nottingham and Leicester. Results: six (9%) of the subjects had a positive response (syncope or presy ncope) to the prolonged head-up tilt test prior to glyceryl trinitrate prov ocation. After provocation, 30 (52%) of the remaining 58 subjects had a pos itive response. Conclusion: the role of sublingual glyceryl trinitrate provocation followin g prolonged head-up tilt testing in the diagnosis of neurocardiogenic (vaso vagal) syncope in older people is questionable, as many asymptomatic older subjects demonstrate syncopal or presyncopal symptoms.