Permanent increase in endothelin serum levels in vasovagal syncope

Area of Science:

• Cardiovascular physiology
• Autonomic nervous system function

Background:

• Vasovagal syncope is a common cause of fainting, often triggered by postural changes.
• Endothelin is a potent vasoconstrictor peptide with implications in cardiovascular regulation.

Purpose of the Study:

• To investigate the role of endothelin in vasovagal syncope during upright tilting.
• To determine if endothelin levels are altered independently of syncope episodes.

Main Methods:

• 40 healthy volunteers underwent two separate upright tilt tests.
• Plasma endothelin levels were measured in supine and head-up tilt positions.
• Vasovagal syncope occurrence was recorded during tilt tests.

Main Results:

• Seven subjects experienced vasovagal syncope during only one of the two tilt tests.
• These subjects consistently showed increased endothelin plasma levels in both supine and head-up positions on both occasions.
• Elevated endothelin levels were observed independent of the vasovagal syncope episodes.

Conclusions:

• Endothelin plasma levels may be a predisposing factor or marker in vasovagal syncope.
• Increased endothelin is present even when syncope does not manifest during tilt testing.
• Further research is warranted to elucidate the precise role of endothelin in autonomic cardiovascular regulation.