A 64-year-old patient with recurrent syncope and a completely unremarkable cardiac workup. Which diagnosis should be considered as a likely cause?

A 64-year-old patient 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)

Exaggerated carotid sinus reflex causing bradycardia and/or hypotension can produce recurrent syncope even when the cardiac evaluation is completely normal. In the elderly, the carotid sinus can become hypersensitive to stimulation, such as turning the head, wearing a tight collar, or minor neck movements, triggering an abrupt vagal response that slows the heart or drops the blood pressure enough to cause loss of consciousness. This reflex syncope fits a pattern where the heart itself isn’t structurally or functionally diseased, so standard cardiac tests come back unrevealing, yet episodes persist due to autonomic reflexes rather than a primary cardiac problem. Subclavian steal would typically have symptoms provoked by arm exercise and show signs of vertebrobasilar compromise rather than isolated recurrent fainting with a normal heart. Orthostatic hypotension would present with a clear drop in blood pressure upon standing, often with volume depletion or autonomic failure clues. Vasovagal syncope is common but often presents with prodrome and can occur at various ages; in a patient with a normal cardiac workup, carotid sinus hypersensitivity remains a leading consideration because it accounts for fainting triggered by neck-related stimuli in older individuals.

Exaggerated carotid sinus reflex causing bradycardia and/or hypotension can produce recurrent syncope even when the cardiac evaluation is completely normal. In the elderly, the carotid sinus can become hypersensitive to stimulation, such as turning the head, wearing a tight collar, or minor neck movements, triggering an abrupt vagal response that slows the heart or drops the blood pressure enough to cause loss of consciousness. This reflex syncope fits a pattern where the heart itself isn’t structurally or functionally diseased, so standard cardiac tests come back unrevealing, yet episodes persist due to autonomic reflexes rather than a primary cardiac problem.

Subclavian steal would typically have symptoms provoked by arm exercise and show signs of vertebrobasilar compromise rather than isolated recurrent fainting with a normal heart. Orthostatic hypotension would present with a clear drop in blood pressure upon standing, often with volume depletion or autonomic failure clues. Vasovagal syncope is common but often presents with prodrome and can occur at various ages; in a patient with a normal cardiac workup, carotid sinus hypersensitivity remains a leading consideration because it accounts for fainting triggered by neck-related stimuli in older individuals.