CORRESPONDENCE: LETTER TO THE EDITOR
Carotid Sinus Hypersensitivity: A Diagnostic Pearl
John R. Kapoor, MD, PhD*
* Division of Cardiology, Stanford University, 300 Pasteur Drive, Stanford, California 94305 (Email: jkapoor{at}stanford.edu).
Syncope is the sixth most common cause of hospitalization in patients older than 65 years (1). As noted by Benditt and Nguyen (2), an accurate diagnosis is the first step when considering treatment options. Of the broad differential diagnosis for syncope, carotid sinus hypersensitivity is often overlooked and is frequently underdiagnosed, although it causes syncope in a significant number of elderly individuals (2,3). The diagnosis of carotid sinus hypersensitivity rests on documenting at least 3 s of asystole (cardioinhibitory type) or a systolic pressure decrease >50 mm Hg (vasodepressor type) during carotid massage (3). Carotid sinus hypersensitivity is often excluded on the basis of a negative response to carotid massage in the supine position (3). However, it should be noted that in a significant proportion of individuals, carotid sinus hypersensitivity is only evident in the upright position. In one study, 68% of patients had documented carotid sinus hypersensitivity, 8.7% in the supine position and 60% in the 60° upright position, increasing the diagnostic yield by 52% and increasing the diagnostic accuracy from 31% in the supine position to 69% in the upright position (4). The positive predictive value increased from 77% to 96% with a specificity of 93% (4). In another study, more than one-half of the positive responses would have been missed if carotid sinus stimulation was not repeated during the head-up tilt (5). In an additional prospective, controlled cohort study of 1,149 subjects presenting with unexplained syncope and drop attacks, 19% had carotid sinus hypersensitivity and 31% of these had a positive response only with head-up tilt, giving the upright positive test 100% specificity and sensitivity (3). The investigators of that study concluded that "the diagnosis of carotid sinus hypersensitivity amenable to treatment by pacing may be missed in one-third of cases if only supine massage is performed" (3). These findings were reinforced in a more recent study in which 59% of subjects had an initial positive response to carotid massage in the upright position (6). Therefore, in testing for carotid sinus hypersensitivity, carotid sinus massage should be performed in the supine and, if negative, in the upright positions. Obtaining an accurate diagnosis of carotid sinus hypersensitivity by these simple maneuvers may decrease the need for invasive and expensive diagnostic investigations for syncope.
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1. Kenny RA, O'Shea D, Walker HF. Impact of a dedicated syncope and falls facility for older adults on emergency beds Age Ageing 2002;31:272-275.[Abstract/Free Full Text]2. Benditt DG, Nguyen JT. Syncope: therapeutic approaches J Am Coll Cardiol 2009;53:1741-1751.[Abstract/Free Full Text] 3. Parry SW, Richardson DA, O'Shea D, Sen B, Kenny RA. Diagnosis of carotid sinus hypersensitivity in older adults: carotid sinus massage in the upright position is essential Heart 2000;83:22-23.[Abstract/Free Full Text] 4. Morillo CA, Camacho ME, Wood MA, Gilligan DM, Ellenbogen KA. Diagnostic utility of mechanical, pharmacological and orthostatic stimulation of the carotid sinus in patients with unexplained syncope J Am Coll Cardiol 1999;34:1587-1594.[Abstract/Free Full Text] 5. McIntosh SJ, Lawson J, Kenny RA. Clinical characteristics of vasodepressor, cardioinhibitory, and mixed carotid sinus syndrome in the elderly Am J Med 1993;95:203-208.[CrossRef][Web of Science][Medline] 6. Parry SW, Steen N, Bexton RS, Tynan M, Kenny RA. Pacing in elderly recurrent fallers with carotid sinus hypersensitivity: a randomised, double-blind, placebo controlled crossover trial Heart 2009;95:405-409.[Abstract/Free Full Text]
Related Article
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Reply
- David G. Benditt and John T. Nguyen
J. Am. Coll. Cardiol. 2009 54: 1633-1634.
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