Carotid sinus hypersensitivity

A 55‐year‐old otherwise healthy woman presented with the first episode of syncope, preceded by sudden onset neck pain, while driving her car at low speed, leading to a minor car accident.

Clinical examinations, brain and neck magnetic resonance imaging scans and echocardiography were unremarkable. Carotid sinus massage on the left carotid body induced the same syncopal symptoms associated with significant sinus pause. The baseline electrocardiogram demonstrated normal sinus rhythm. A non‐conducted P wave (Figure, arrow) was noted soon after the carotid sinus massage followed by a prolonged episode of sinus arrest (10.4 seconds). This was consistent with high vagal tone resulting in transient sinoatrial and atrioventricular nodes block. The sinoatrial node activity slowly resumed once carotid sinus massage was ceased. She was diagnosed with carotid sinus hypersensitivity and underwent permanent pacemaker implantation.

Carotid sinus hypersensitivity is a rare condition usually seen in older men.1,2 This case, however, reminds us that carotid sinus hypersensitivity should be excluded when dealing with syncope of unknown aetiology even in younger patients.