What is the Difference Between Orthostatic Hypotension and Vasovagal Syncope?

Orthostatic hypotension and vasovagal syncope are both conditions that can cause fainting, but they have distinct differences in their underlying mechanisms and symptoms.

Orthostatic Hypotension:

• Occurs due to a failure in compensating for the fluid shift that follows postural change, such as moving from a supine to an upright position.
• Develops in a short period, usually within a minute of standing.
• Characterized by an early and progressive decline in blood pressure (BP).
• Often associated with neurogenic orthostatic hypotension, which can be differentiated from vasovagal syncope by its differing hemodynamic patterns during tilt table test.

Vasovagal Syncope:

• Also known as neurally mediated syncope or reflex syncope, it is triggered by an exaggerated response to certain stimuli, such as pain, anxiety, or stress.
• Typically occurs after prolonged sitting or standing, and the latency of syncope onset after the orthostatic challenge is longer than that of orthostatic hypotension.
• Characterized by a sudden drop in BP and heart rate (HR).
• Often associated with prodromal vagal symptoms, such as cold sweating or nausea, which are not present in orthostatic hypotension.

In summary, the main differences between orthostatic hypotension and vasovagal syncope are the latency of syncope onset after the orthostatic challenge, the presence or absence of prodromal vagal symptoms, and the hemodynamic patterns observed during tilt table tests.

Comparative Table: Orthostatic Hypotension vs Vasovagal Syncope

Here is a table comparing the differences between Orthostatic Hypotension and Vasovagal Syncope:

Vasovagal Syncope is a type of neurally mediated syncope, and it is often characterized by a sudden drop in blood pressure and heart rate during a head-up tilt table test. In contrast, Orthostatic Hypotension is characterized by an early and progressive decline in blood pressure during the same test. The age of onset, gender distribution, and symptoms with body position changes also differ between the two conditions.