Is it right to say that always syncope is a result of low perfusion to brain, or low blood pressure?

(I know that there are a lot of secondary reasons such as vassovagal or cardiac issues, but if I understand well all of these reasons bring to the condition of low blood pressure which causes the syncope.)

1 Answer 1



The definition of syncope is exactly that, hypo-perfusion in the brain. This is usually caused by a sudden drop in blood pressure such as in a vaso-vagal syncope where a strong vagal response triggers sudden dilation of arteries (vasodilation) and decreases the heart rate. The same goes for heart conditions called arrhythmias cause an abnormal heartbeat (sometimes very slow or very fast) that leads to a drop in blood pressure.

The response to this hypo-perfusion is a sudden loss of consciousness and muscle tone. This leads to collapse leaving the head/brain at the same level as the heart. This makes the return of venous blood from the lower body easier as it no longer travels against gravity and blood must no longer travel against gravity to the brain. This in turn makes the hearts job of perfusing the brain easier leading to a rapid recovery of consciousness. That's at least the rough concept.

Here is an article about syncope, it's clinical symptoms, and physiology: https://academic.oup.com/brain/article/132/10/2630/329792/Symptoms-and-signs-of-syncope-a-review-of-the-link

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