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KEY FEATURES

ESSENTIALS OF DIAGNOSIS

  • Syncope or near syncope occurring during carotid sinus stimulation

  • Precipitating events such as shaving or looking up may be reported

  • Syncope tends to be abrupt, and the patient may not recall a specific maneuver

  • Occurs in older patients

  • Bradycardia and vasodepressor element may both play a role

GENERAL CONSIDERATIONS

  • Pure cardioinhibitory response is most common (60–80%)

  • Pure vasodepressor response is rare (5–10%)

  • The remainder is of a mixed variety

  • Syncope or near syncope may occur during carotid sinus stimulation or fortuitous Holter monitoring showing asystole during maneuvers of carotid sinus stimulation

  • Increased vagal activity and inhibition of peripheral sympathetic activity occur as part of carotid sinus reflex

  • Heightened response to carotid sinus pressure

  • Frequently associated with coronary artery disease

  • Tendency to occur in older patients

  • Maneuvers that precipitate syncope may include:

    • – Tight collars

    • – Heavy lifting

    • – Trumpet playing

    • – Sometimes the pressure of a seatbelt

  • May be a cause of symptoms such as shortness of breath, angina, and syncope in patients with atrial fibrillation

  • Carotid aneurysm and head-neck tumors can predispose to CSH

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

  • Dizziness

  • Presyncope

  • Syncope

  • May present as unexplained falls

PHYSICAL EXAM FINDINGS

  • No specific features other than reproduction of symptoms on carotid sinus pressure

  • May have features of coexistent coronary heart disease or carotid bruit

DIFFERENTIAL DIAGNOSIS

  • Neurocardiogenic syncope

  • Ventricular tachycardia may coexist with carotid sinus hypersensitivity, particularly in patients with previous myocardial infarction or systolic dysfunction

DIAGNOSTIC EVALUATION

LABORATORY TESTS

  • CBC, basic metabolic panel

ELECTROCARDIOGRAPHY

  • ECG to identify previous myocardial infarction and arrhythmic disorders

  • Ambulatory cardiac monitoring to document episodes and detect rhythm disturbances

IMAGING STUDIES

  • Generally not required unless there is evidence of underlying structural heart disease

DIAGNOSTIC PROCEDURES

  • Carotid sinus massage (contraindicated if there is a bruit, history of stroke, or carotid surgery)

  • The carotid sinus massage should be done with ECG and hemodynamic monitoring

  • The duration of the massage should not exceed 5–10 seconds

  • Comprehensive evaluation includes both supine and upright carotid sinus massage

  • Cardioinhibitory response is defined as ≥ 3 seconds of ventricular standstill (terminate carotid pressure at the onset of asystole)

  • Vasodepressor response is defined as a drop in systolic blood pressure of ≥ 50 mm Hg

TREATMENT

CARDIOLOGY REFERRAL

  • All patients with a clinical suspicion of carotid sinus hypersensitivity should be evaluated by a cardiac electrophysiologist

HOSPITALIZATION CRITERIA

  • If marked asystole is documented (> 3 seconds), then hospitalization is warranted until definitive treatment

  • A patient with concomitant ...

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