Introduction
Carotid sinus hypersensitivity (CSH) is an exaggerated response to a carotid sinus baroreceptor stimulation. It causes dizziness or syncope due to a temporary decrease in cerebral perfusion. Although baroreceptor function usually decreases with age, some people may experience hypersensitive carotid baroreflexes. It most commonly affects older males. Studies report that CSH is found in 0.5 to 9.0 % of United States patients with recurrent syncope. In the international scenario, CSH has been reported in up to 14 % of elderly nursing home patients, and unexplained syncope and drop attacks are experienced by 30 % of elderly patients. This condition is more common in elderly individuals. It rarely affects people younger than 50 years.
How Is Carotid Sinus Hypersensitivity Caused?
CSH can be caused due to the following:
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Increased age.
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More likely to affect males.
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Hypertension.
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Orthostatic hypotension.
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Coronary artery disease.
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Vasovagal syncope.
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Alzheimer disease.
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Dementia associated with Lewy body.
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Concurrent medications along with beta-blockers, digitalis, and methyldopa.
What Are The Signs And Symptoms of Carotid Sinus Hypersensitivity?
Many patients do not show any symptoms.
The following signs and symptoms can be observed in those who are symptomatic:
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Recurrent syncope (fainting).
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Recurrent dizziness, near-syncope.
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Non-accidental or unexplained falling.
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Neck tumors, extensive neck scarring secondary to radical dissection or radiation fibrosis, or neck trauma.
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Possible prodrome or retrograde amnesia in case the patient experiences a syncope attack.
Taking carotid pulse or during head and neck surgery, the person may show signs and symptoms.
Following are the signs that can be noted while examining the patient:
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Hypotension (decreased blood pressure).
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Asystole.
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Bradycardia (decreased heartbeat).
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Auscultation for carotid artery bruit before consideration of carotid sinus massage.
How Can Carotid Sinus Hypersensitivity Be Diagnosed?
When you visit your physician, you will be asked certain questions regarding your signs and symptoms, medications, and family history. Following that, a physical examination will be carried out. Also, carotid sinus massage can be performed on a patient with cerebrovascular disease, or auscultation can reveal carotid bruit which can precipitate neurologic manifestations. It is important to advise patients with severe symptoms attributed to CSH not to drive vehicles until a physician suggests.
Various other types of syncope can mimic carotid sinus hypersensitivity, which are as follows:
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Orthostatic hypotension.
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Vasovagal syncope.
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Situational syncope like those related to cough, micturition, swallowing, and defecation.
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Cardiogenic syncope.
Hence, any patient suggestive of syncope should be assessed using the following:
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A carefully elicited history of the patient.
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A complete physical examination.
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An ECG.
Procedures performed during examination:
Carotid sinus massage is the main diagnostic method of choice, but there is no standardized technique till now as there are not enough controlled studies on the same.
The commonly accepted massage method that the physician follows includes the following steps:
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Place the patient in a supine position and extend the neck slightly. The patient should lie supine for 5 minutes before a carotid sinus massage.
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Massage should be performed over the point of maximal carotid impulse, medial to the sternomastoid muscle located at the upper border level of the thyroid cartilage.
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Massage should be continued for 5 to 10 seconds consecutively on each carotid sinus, and a one-minute interval should be given between massages.
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Carotid sinus massage is preferably first done on the right carotid sinus as CSH is observed more commonly on the right than on the left side.
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Surface ECG and blood pressure should be monitored continuously.
How Is Carotid Sinus Hypersensitivity Treated?
Management of carotid sinus hypersensitivity (CSH) depends on the frequency, severity, and consequences of symptoms in each patient. Most of the patients can be managed with the help of education, changes in lifestyle, expectancy, and regular follow-up.
Those who experience incapacitating and recurrent symptoms may require the following treatments:
Medical Care
1. Pharmacotherapy has been used to manage recurrent, symptomatic conditions. However, no single medicine has been proven to provide long-term effectiveness in various studies.
2. Permanent pacemaker implantation is another option that is generally considered an effective treatment in patients diagnosed with cardioinhibitory CSH and mixed forms of CSH. According to the American College of Cardiology/American Heart Association/Heart Rhythm Society, current clinical practice guidelines suggest permanent pacing therapy as a class I indication. It means that general agreement exists that this therapy is effective and beneficial in patients experiencing recurrent syncope caused by carotid sinus stimulation without any drug that can depress the sinus node or atrioventricular conduction. Permanent pacing is considered a class IIa indication in patients with recurrent syncope without clear, provocative events and who have a hypersensitive cardioinhibitory response. Permanent pacing is contraindicated in patients with a hypersensitive cardioinhibitory response to stimulation of the carotid sinus without symptoms.
3. Volume maintenance is another option that can control the vasodepressor form of CSH. It maintains adequate central volume and, thus, prevents syncope. Patients without other cardiovascular diseases should be advised to increase their salt intake and drink more fluids containing electrolytes.
Surgical Care
Surgical denervation and radiological denervation of the carotid sinus nerve were the methods preferred in earlier days. These have been eradicated as they tend to cause more complications. Surgery remains an option for those patients who have a neck tumor that is compressing the carotid sinus.
Daily Activities
There are no such restrictions. Patients should be aware of prodromal symptoms, which can cause presyncope or syncope. If they experience such symptoms, they should be advised to assume a supine posture to prevent syncope and/or falls. There are various precipitating factors like wearing tight neck collars or rotating the neck suddenly, and patients should avoid these. Also, patients should undergo regular follow-ups as their physician or specialist recommends.
Conclusion
Carotid sinus hypersensitivity (CSH) mainly leads to syncope or syncope-like symptoms. You can consult a specialist online through online medical platforms to know more about this condition.
