Syncope implies transient global cerebral dysfunction and is one of the most common reasons for hospital admission. The underlying cause of syncope can include cardiac or noncardiac factors or may be related to a combination of factors in entities such as neurocardiogenic syncope. Defining the cause of syncope and instituting the proper preventative therapy is important, particularly given the fact that syncope may have significant morbidity and tends to be recurrent. However, detecting an abnormality that may be a cause for syncope does not necessarily mean that the abnormality is the cause for syncope in the particular patient being evaluated—the clinician is often faced with the question whether the relationship between clinical presentation and a test abnormality is cause and effect or an association. This is particularly important when there is a high prevalence of an abnormality in the general population, as highlighted in an article published in this issue of the ARCHIVES, in which Kerr et al1 found that 39% of an unselected population older than 65 years had carotid sinus hypersensitivity.
Coplan NL. Carotid Sinus Hypersensitivity and SyncopeCause/Effect or True/True/Unrelated. Arch Intern Med. 2006;166(5):491-492. doi:10.1001/archinte.166.5.491