[Investigation in suspected syncope. A study of more than 1,174 consecutively referred patients]

Syncope is a common cause of acute hospitalization and may be associated with poor quality of life. History and physical examination can exclude most frequent cardiac or neurological causes, leaving two main diagnostic groups--postural and reflex syncope. The purpose of the study was to compare two forms of tilt testing and to describe the diagnostic patterns associated with these methods.

The study included 1,174 patients (722 women) aged 11 to 96 years consecutively referred from primary (24.6%) and secondary care units (75.4%). Two groups of equal size were studied by the standard tilt tests with or without nitroglycerine administration. Blood pressure and heart rate were monitored continuously by non-invasive methods.

The diagnostic yield was 29% and 64% without and with nitroglycerin, respectively (p < 0.0001). The diagnostic yield was independent of age and sex but reflex syncope occurred more often in women and postural syncope was more common in men (p < 0.0001). Postural syncope dominated in patients over 55 years whereas reflex syncope dominated in younger patients (p < 0.0001).

The diagnostic yield and the pattern of outcome from tilt testing are highly dependent upon the selected protocol.

Postural and reflex syncope occur in all age groups, but the former is more frequent in the elderly and the latter more frequent in the young. The use of nitroglycerine significantly increases the diagnostic yield of tilt testing.