Carotid Sinus Hypersensitivity Workup

Updated: Sep 12, 2016
  • Author: Mevan N Wijetunga, MD, FACC, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Workup

Laboratory Studies

The initial diagnostic workup for carotid sinus hypersensitivity (CSH) should rule out the following:

  • Vasovagal syncope
  • Orthostatic hypotension
  • Situational syncope
  • Sick sinus syndrome
  • Cardiogenic syncope
  • Other causes of syncope (eg, neurogenic, metabolic, psychogenic)

Any patient with syncope should be evaluated with the following:

  • A carefully elicited history
  • A thorough physical examination
  • An ECG
Next:

Procedures

Carotid sinus massage is the diagnostic maneuver of choice, but the technique has not been standardized. There are no controlled studies on the subject. [17, 18]

A commonly accepted massage method includes the following 4 steps:

  • Place the patient in the supine position with the neck slightly extended. The patient should lie supine for a minimum of 5 minutes before carotid sinus massage is applied.
  • Massage over the point of maximal carotid impulse, medial to the sternomastoid muscle at the upper border level of the thyroid cartilage.
  • Massage for 5-10 seconds on each carotid sinus consecutively, with a 1-minute interval between massages.
  • Carotid sinus massage is preferably applied to first the right carotid sinus, as CSH is more prevalent on the right than on the left side.
  • Continuously monitor surface ECG and blood pressure. Phasic, noninvasive, beat-to-beat blood pressure monitoring is preferred over using a cuff measurement.

A massage is considered to have a positive result if any of the following 3 criteria are met:

  • Asystole exceeding 3 seconds (indicates cardioinhibitory CSH)
  • Reduction in systolic blood pressure exceeding 50 mm Hg independent of heart rate slowing (indicates vasodepressor CSH)
  • Combination of the above (indicates mixed CSH)

A less frequently used method consists of carotid sinus massage performed for 5 seconds on each side in the supine and 60º positions using the head-up tilt table. Substantial evidence shows that sensitivity and diagnostic accuracy of carotid sinus massage can be enhanced by performing the test with the patient in an upright position. Furthermore, the endpoint of a 50 mm Hg reduction in systolic blood pressure may be achieved with tilt, but not when supine.

Do not perform a carotid sinus massage if the patient is known to have transient ischemic attack, stroke, or myocardial infarction in the preceding 3 months. History of ventricular tachycardia, ventricular fibrillation, or carotid bruit on auscultation are relative contraindications to carotid sinus massage.

Some authors describe the use of carotid Doppler ultrasonography to guide carotid sinus massage in patients who have a carotid bruit on auscultation. Carotid sinus massage is performed only in patients with a carotid bruit when there is less than 70% stenosis on Doppler examination.

Although carotid sinus massage is usually a benign bedside procedure, a few case reports describe rare neurological deficit symptoms following the massage. Currently, the estimated incidence of neurological complications is less than 0.2%.

A single case report describes the induction of coronary artery spasm by carotid sinus massage.

Rare case reports describe the induction of atrial or ventricular arrhythmias by carotid sinus massage.

Carotid massage has its greatest clinical utility in elderly patients aged 60-80 years.

The positive predictive value of carotid massage remains undefined. Therefore, a clinician who finds a sensitive carotid sinus should consider other prognostically important causes of syncope and the presence of comorbid conditions.

In recent years, the scientific basis of the current diagnostic criteria for carotid sinus hypersensitivity (ie, blood pressure drop of ≥50 mm Hg and/or asystole of ≥3 s with carotid sinus massage) are called into question. Because the existing criteria is too sensitive to detect carotid sinus hypersensitivity, authors propose a new set of criteria (ie, blood pressure drop of ≥60 mm Hg, lasting for >6 s and/or asystole of ≥6 s with carotid sinus massage). This new set of criteria has yet to be validated by prospective studies. [12, 19]

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