Carotid sinus syndrome: Progress in understanding and management.

Area of Science:

• Autonomic Nervous System Disorders
• Cardiovascular Medicine
• Neurology

Background:

• Carotid sinus syndrome (CSS) is a condition causing syncope, particularly in older males with cardiovascular disease.
• Epidemiological data and etiology of CSS are not well-established.
• CSS patients represent approximately 9% of syncope cases presenting to specialist facilities.

Purpose of the Study:

• To define Carotid Sinus Syndrome (CSS) and its diagnostic methodology.
• To outline therapeutic strategies for different CSS subtypes.
• To highlight the importance of Carotid Sinus Massage (CSM) in diagnosing CSS.

Main Methods:

• Carotid sinus massage (CSM) performed supine and upright with continuous ECG and BP monitoring.
• Reproduction of spontaneous symptoms during CSM defines CSS.
• Assessment of vasodepressor component using the 'method of symptoms' with atropine.

Main Results:

• Cardioinhibitory CSS involves asystole (>3s) on CSM; vasodepressor CSS involves a significant BP drop (>50 mmHg).
• Dual-chamber pacing is effective for cardioinhibitory CSS, especially with a negative tilt test.
• Therapy for vasodepressor CSS is often unrewarding, necessitating alternative treatments.

Conclusions:

• CSS diagnosis relies on specific responses to CSM, differentiating it from Carotid Sinus Hypersensitivity (CSH).
• Dual-chamber pacing is the primary therapy for cardioinhibitory CSS.
• Management of vasodepressor CSS requires exploring alternative therapeutic measures beyond pacing.