NEW YORK (Reuters Health) Mar 22 - While carotid sinus hypersensitivity (CSH) is the most commonly reported cause of syncope and falls in the elderly, it is also seen in about a third of those who have not experienced such events, UK researchers report in the March 13th issue of the Archives of Internal Medicine.

To determine the prevalence of CSH, Dr. Simon J. Kerr of Newcastle General Hospital and colleagues randomly sampled patients over 65 years of age from a single general practice. In all, 272 underwent supine and upright carotid sinus massage with continuous heart rate and phasic blood pressure monitoring -- the recommended diagnostic procedure.

CSH was defined as asystole for 3 seconds or longer and/or a drop in systolic blood pressure of 50 mm Hg or greater. CSH was present in 107 (39%) of the subjects, and 16% had symptoms including syncope.

Of 80 previously asymptomatic subjects, 28 (35%) had CSH.

Given that CSH is a common finding, the researchers conclude that its presence "should not necessarily preclude further investigation for other causes of syncope."

Dr. Neil L. Coplan of Lenox Hill Hospital, New York, author of an accompanying editorial told Reuters Health that "if carotid sinus hypersensitivity is associated with symptoms, it should be considered as a likely possibility to explain the cause for the presenting complaint and treatment should be instituted."

However, "if there are no symptoms associated with the exaggerated carotid artery reflex or if the carotid sinus hypersensitivity is demonstrated in a patient who does not have a complaint of transient neurological symptoms, the clinical significance of the carotid sinus massage results needs to be questioned," he advised.