Independent role of reduced arterial baroreflex sensitivity during head-up tilt testing in predicting vasovagal syncope recurrence.

Aims: The involvement of arterial baroreflex function in the pathophysiology of vasovagal syncope (VVS) is controversial, and there are no published data supporting its clinical usefulness. The aim of this study was to evaluate the role of arterial baroreflex sensitivity (BRS) at baseline and during head-up tilt testing (HUT) in predicting the recurrence of VVS.

Methods And Results: The study involved otherwise healthy patients with a history of unexplained syncope who underwent diagnostic HUT by being tilted to 70 degrees after 10 min supine rest; the test was potentiated by the administration of 300 microg of nitroglycerine (NTG) after 20 min.

Lack of association between genetic polymorphisms affecting sympathetic activity and tilt-induced vasovagal syncope.

Although the pathophysiology of vasovagal syncope is not completely understood, the involvement of sympathetic nervous system alterations has been suggested. Since predisposition to fainting during orthostatic challenge may be associated with genetic variations, we sought to explore the role of genetic polymorphisms affecting sympathetic nervous system function in the susceptibility to tilt-induced vasovagal syncope. We genotyped 129 subjects with recurrent unexplained syncope who underwent tilt testing, and investigated the recurrence of syncope.

Clinical predictors of head-up tilt test outcome during the nitroglycerin phase.

Objectives: Nitrate-stimulated head-up tilt testing (HUT) is currently recommended to confirm the diagnosis of vasovagal syncope in subjects with syncope of unknown origin. Given the few data currently available, the aim of this study was to assess correlations between nitrate-induced HUT outcomes and the clinical characteristics of patients.

Methods: Two hundred and thirty consecutive, otherwise healthy subjects with a history of recurrent unexplained syncope underwent HUT.

Endothelin system polymorphisms in tilt test-induced vasovagal syncope.

Introduction: Genetics may be involved in the pathophysiology of vasovagal syncope. The 3A/4A polymorphism of the EDN1 gene affects the expression of endothelin-1, and the H323H T/C polymorphism of the EDNRA gene encoding for the endothelin type A receptor has been associated with cardiovascular pathologies. As the endothelin system participates in the regulation of cardiovascular homeostasis, the aim of this study was to analyse the role of these genetic variants in influencing tilt-induced vasovagal syncope.

Endothelin system polymorphisms in tilt test-induced vasovagal syncope.

Objectives: As the endothelin system participates in the regulation of cardiovascular homeostasis, the aim of this study was to analyse the role of endothelin system polymorphisms in influencing tilt-induced vasovagal syncope.

Methods: We evaluated 107 otherwise healthy subjects with recurrent unexplained syncope who underwent a head-up tilt test. All subjects were genotyped for the 3A/4A polymorphism of the EDN1 gene and the H323H T/C polymorphism of the EDNRA gene.