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 provocation are increasingly used in the diagnosis of neurocardiogenic syncope. However 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 followed 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. Exclusion criteria were: history of syncope, ischaemic heart disease, cerebrovascular disease, marked aortic stenosis, carotid artery disease and being unable to stand for the duration of the test. hll subjects underwent a full clinical examination, a 12-lead electrocardiogram and a 30-40-min head-up tilt test, during which we monitored the heart rate and blood pressure continuously. We ended the test prematurely if the subjects developed syncope or symptoms of presyncope associated with hypotension with or without bradycardia. If they remained asymptomatic at the end of this period, they received 400 mug of sublingual glyceryl trinitrate and monitoring continued for another 15 min. Settings: two teaching hospitals in Nottingham and Leicester. Results: six (9%) of the subjects had a positive response (syncope or presyncope) to the prolonged head-up tilt test prior to glyceryl trinitrate provocation. After provocation, 30 (52%) of the remaining 58 subjects had a positive response. Conclusion: the role of sublingual glyceryl trinitrate provocation following prolonged head-up tilt testing in the diagnosis of neurocardiogenic (vasovagal) syncope in older people is questionable, as many asymptomatic older subjects demonstrate syncopal or presyncopal symptoms.