The March 12, 2006 issue of the Archives of Internal Medicine has an interesting article on the issue of syncope and carotid sinus hypersensitivity and a useful related editorial.
The editorialist make a good point about the contraindications for carotid sinus massage (CSM) as a diagnostic maneuver. The presence of a bruit has traditionally been considered a contraindication but because of the limited diagnostic value of listening over the neck arteries Dr. Neil Coplan suggests it would make more sense to do a carotid ultrasound first if there is concern about the presence of carotid artery disease. And in an elderly patient with a history of syncope you would almost always have that concern and the suggestion is that the absence of a bruit may not be sufficient reassurance.
The article, itself,showed that among community dwelling older folks in England, carotid sinus hypersensitivity was seen in 35 % of the sample ( n=1,000) who did not have a history of falls, syncope or even dizziness. So the point is that a positive result on CSM does not necessarily mean that the patient with syncope has carotid sinus hypersenstivity as the cause and other causes still need to be ruled out. How do you determine if the hypersensitivity is the causative? Basically you check out the other likely suspects and make a clinical judgment.
Since carotid sinus hypersensitivity may be fairly common in the older population, a comment regarding safe use of stethoscope seems in order. At some point in time, which so far has not been accurately pinpointed by medical historians, a sea change occurred in the way stethoscopes are worn. Older docs may still place the ear pieces around the back of the neck while younger ones drape the instrument around the neck with the ear pieces dangling on one side of the chest and the heads of the instruments on the other. Why or when this important cultural change occurred is unclear and the ergonomic issues need to be discussed but older docs need to shift to the modern method if for no other reason than to avoid syncope. This link shows the safe way to carry your stethoscope when not in use and on this link we see Dr. Kildare with the style of another stethoscope era.. Another reason that it is good to keep current.