Endothelin system polymorphisms in tilt test-induced vasovagal syncope.

Area of Science:

• Cardiovascular Genetics
• Autonomic Nervous System Disorders

Background:

• Vasovagal syncope (VVS) pathophysiology may involve genetic factors.
• The endothelin system plays a role in cardiovascular homeostasis.
• Genetic variations in endothelin-1 (EDN1) and endothelin type A receptor (EDNRA) genes are implicated in cardiovascular conditions.

Purpose of the Study:

• To investigate the association between EDN1 (3A/4A) and EDNRA (H323H T/C) gene polymorphisms and tilt-induced vasovagal syncope.
• To determine if these genetic variants influence susceptibility to VVS and hemodynamic responses during tilt testing.

Main Methods:

• Cardiovascular parameters were recorded in 107 patients with recurrent unexplained syncope undergoing head-up tilt testing.
• Genotyping for EDN1 3A/4A and EDNRA H323H T/C polymorphisms was performed.
• Statistical analyses, including univariate and multivariate assessments, were conducted.

Main Results:

• The 4A allele of the EDN1 gene was significantly more frequent in patients who fainted during tilt testing (tilt-positive).
• Carriers of the 4A allele were more likely to exhibit a vasodepressive pattern compared to homozygous 3A allele carriers.
• No significant association was found for the EDNRA H323H T/C polymorphism.

Conclusions:

• The 3A/4A polymorphism of the EDN1 gene influences susceptibility to vasovagal syncope.
• The 4A variant, potentially linked to increased endothelin-1 expression, may predispose individuals to vasodepressive responses during tilt-induced syncope.