An older patient presents to the ER with recurrent syncope and a completely unremarkable cardiac workup. Which diagnosis should be considered as a likely cause?

• A. Subclavian Steal Syndrome
• B. Orthostatic Hypotension
• C. Carotid Sinus Hypersensitivity
• D. Vasovagal Syncope

Answer: (C)

In older patients with recurrent syncope and a completely normal cardiac evaluation, a reflex-mediated cause is likely, with carotid sinus hypersensitivity being a classic option. The carotid sinus contains baroreceptors that regulate heart rate and blood vessel tone. When these receptors are overly sensitive, even mild stimulation of the neck or carotid sinus—such as turning the head, wearing a tight collar, or shaving—can trigger an exaggerated vagal response and/or withdrawal of sympathetic tone. The result is sudden bradycardia, or hypotension, or both, leading to cerebral hypoperfusion and fainting.

This pattern fits an elderly patient whose heart looks fine on tests but who has recurrent fainting episodes. Diagnostically, carotid sinus massage with continuous monitoring can reproduce the response if the reflex is present, helping confirm the diagnosis, though it must be done with caution to minimize risk. Management focuses on avoiding triggers, reviewing medications that might blunten heart rate or blood pressure, and addressing the specific reflex component—cardioinhibitory types may require pacing if bradycardia is severe, while vasodepressor types benefit from measures to maintain volume and blood pressure.